CONSOLIDATING SPACER FLUI DS AND METHODS OF USE
BACKGROUND
[0001] The present invention relates to spacer fluids for use in subterranean operations
and, more particularly, in certain embodiments, to consolidating spacer fluids and methods of use
in subterranean formations
[0002 Spacer fluids a e often used in subterranean operations to facilitate improved
displacement efficiency when introducing new fluids into a well bore. For example, a spacer
fluid can be used t displace a fluid in a well bore before introduction of another fluid. When
used for drilling fluid displacement, spacer fluids can enhance solids removal as well as separate
the drilling fluid from physically incompatible fluid. For instance, in primary cementing
operations, the spacer fluid may be placed into the well bore to separate the cement composition
from the drilling fluid. Spacer fluids may also be placed between different drilling fluids during
drilling change outs or between a drilling fluid and completion brine. Spacer fluids typically do
not consolidate in that the spacer fluids typically do not develop significant gel or compressive
strength.
[0003] To he effective, th spacer fluid can have certain characteristics. For example, th
spacer fluid may be compatible with the displaced fluid and the cement composition. 'This
compatibility may also be present at downhole temperatures and pressures. In some instances it
is also desirable for the spacer fluid to leave surfaces in the well bore water wet, thus facilitating
bonding with th cement composition. Rheology of the spacer fluid can also be important. A
number of different theological properties may e important in the design of a spacer fluid,
including yield point, plastic viscosity, gel strength, and shear stress, amo g others. While
rheology can be important in spacer fluid design, conventional spacer fluids may not. have the
desired rheology at downhole temperatures. For instance, conventional spacer fluids ma
experience ndes red thermal thinning at elevated temperatures. As a -result, conventional spacer
fluids may not provide the desired displacement in some instances.
SUMMARY
[0004] The present invention relates to spacer fluids for use in subterranean operations
and, more particularly, in certain embodiments, to consolidating spacer fluids an methods of use
in subterranean formations..
[0005] An embodiment may comprise displacing a drilling fluid disposed in a well bor
annulus, comprising: designing a spacer fluid to meet at least one property under predetermined
well bore conditions, wherein the property is selected from the group consisting of: ) a yield
point of from about 25 Pascals to about 250 Pascals, (ii) a static gel strength of f o about 70
f ! ft t about 500 b !OO f (iii) a yield limit in compression from abou I psi to about
2,000 psi, and (iv) a unconfined uniaxial compressive strength of from about 5 psi to about
10,000 psi; using the- spacer fluid to displace at least a portion of the drilling fluid from the wei
bore annulus; and allowing at least a portion of the spacer fluid to consolidate n the well bore,
and wherein the portion o f the spacer fluid consolidates in the well bore to meet the property.
[0006] Another embodiment ma comprise a method of displacing a drilling fluid
disposed in a we l bore annulus, comprising: usi g a consolidating spacer fluid to displace at least
a portion of the drilling fluid f om the we l bo e annulus; and allowing at least a portion of the
consolidating spacer fluid to consolidate in the well bore annulus, wherein the portion of the
consolidating spacer fluid has a zer gel time of about 4 hours or less.
[0007] Another embodiment ma comprise a method of displacing a drilling Ouid
disposed in a e l bore annulus, comprising: using a consolidating spacer fluid to displace at least
a portion of the drilling fluid fr o the wel bore annulus.; and allowing at least a portion of the
consolidating spacer fluid to consolidate in the wel bore annulus, wherein the portion of the
consolidating spacer fluid has a transition time of about 45 minutes or less,
[0008] Another embodiment may comprise a method of displacing a drilling fluid
disposed in a well bore annulus, comprising: introducing a consolidating spacer fluid into the we
bore annulus to displace at least a portion of the drilling fluid from the well bore annulus; and
allowing at least a portion of the consolidating spacer fluid to consolidate n the well bore
annulus; wherein the consolidating spacer fluid comprises water and at least one additive selected
from the group consisting of kiln dust, gypsum, fly ash, ben oni e, hydroxyethyl cellulose,
sodium silicate, a hollow microsphere, gilsonjte, perlite, a gas, an organic polymer, a biopolymer,
latex, ground rubber, a surfactant, crystalline silica, amorphous silica, silica flour, fumed silica,
nano-clay, salt, fiber, hydratable clay, rice usk ash, micro-fine cement, metakaolm, zeolite,
shale, pumicite, Portland cement, Portland cement interground with pumice, barite, slag, lime,
and any combination thereof; and wherein the portion of the consolidating spacer fluid has a zero
gel time of about S hours or less.
[0009] Another embodiment may comprise a method of displacing drilling fluid
disposed in a well bore annulus, comprising: introducing a consolidating spacer fluid into the well
bore annulus to displace at least portion of the drilling fluid fro the well bore annulus;
allowing at least a portion of the consolidating spacer fluid to consolidate in the well bore
annulus; and measuring consolidation properties of the portion of the consolidating spacer fluid in
the well bore annulus.
Another embodiment of a method of may comprise a method of evaluating a
spacer fluid for use in separating a drilling fluid a d a cement composition in a well bore
comprising: providing the spacer fluid; and measuring a transition time of the spacer fluid.
[0 0 t j Another embodiment may comprise a etho of evaluating spacer fluid for use
in separating a drilling fluid and a cement composition in a well bore comprising: providing the
spacer fluid; and measuring a zero gel ti of the spacer fluid,
[0012] Another embodiment may comprise a consolidating spacer fluid that separates a
drilling fluid a d a cement composition in a well bore, comprising; water; and at least one
additive selected from the group consisting of kiln dust, gypsum, fly ash, ben oni e, hydroxyethyi
cellulose, sodium silicate, a hollow microsphere, gilsonite, perlite, a gas, an organic polymer, a
biopoSyrner, latex, ground rubber, a surfactant, crystalline silica, amorphous silica, silica flour,
fumed silica, nano-c ay salt, fiber, hydratable clay, rice husk ash, micro-line cement, metakaolin,
zeolite, shale, pu ite, Portland cement. Portland cement interground with pumice, barite, slag,
ime, and an combination thereof; and wherein the portion of the consolidating spacer fluid has a
zero ge time of about 4 hours or less.
[00 13] The features and advantages of the present invention will be readily apparent to
those skilled in the art. While numerous changes may e made by those skilled in the art, such
changes are within the spirit of th invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[00 4] These drawings illustrate certain aspects of some of the embodiments of the
present invention, and should ot b used to limit or define the invention.
[0015] F G. 1 is a graph showing measured static gel strength values at various
temperature and pressure readings as a factor of time for an example consolidating spacer fl uid
[00 ] FIG. 2 s a grap showing measured static gel strength values at. various
temperature and pressure readings as a factor of time for an example conso dating spacer fl uid
DESCRIPTION OF PREFERRED EMBODIMENTS
[00 ] The present invention relates to spacer fluids for use in subterranean operations
and, more particularly, n certain embodiments, to spacer fluids that comprise cement kil dust.
( C " ) and methods that use C D for enhancing one or more rheological properties of a spacer
fluid. I accordance with present embodiments, the spacer fluids may improve the efficiency of
well bore cleaning and well bore fluid removal. Embodiments of the spacer fluids ay be
foamed. Embodiments of the spacer fluids may be consolidating. For example, the spacer fluids
may develop gel strength and/or compressive strength when left in a well bore.
[0 8] There ma e several potential advantages to the methods and compositions of the
present invention, on y some of which ay b alluded to herein. One of the ma y potential
advantages of the methods and compositions of the present invention s that the CKD may be
used in spacer fluids as a theology modifier allowing formulation of a spacer fluid with desirable
rheologieal properties. Another potential advantage of the methods and compositions of the
present invention is that inclusion of the C D i the spacer fluids may result n a spacer fluid
without undesired thermal thin ing Yet another potential advantage of the present invention s
tha spacer fluids comprising CKD may b more economical than conventional spacer fluids,
which are commonly prepared with higher cost addit es. Yet another potential advantage of he
present invention is that foamed spacer fluids comprising CKD may b used for displacement of
lightweight drilling fluids. Yet another potential advantage is tha the consolidating spacer fluids
ay possess additional physical characteristics that can provide additional benefits to the we l
bore operations. For example, the consolidating spacer fluids ma develop gel and/or
compressive strength in a well bore annulus. Accordingly, the consolidating spacer fluid left n
th well bore may function to provide a substantially impermeable barrier to seal off formation
fluids and gases and consequently serve to mitigate potential fluid migration. The consolidating
spacer fluid in the well bore annulus may also protect the pipe string or other conduit from
corrosion. Consolidating spacer fluids may a so serve to protect the erosion of the cement sheath
formed by subsequently introduced cement compositions.
[0 Embodiments of the spacer fluids of the present invention ma comprise water
and CKD. in some embodiments, the spacer fluids ay conso date when left in a well bore. For
example, the spacer fluid .may set and harden by reaction of the CKD in the water. In some
embodiments, the spacer fluids may b foamed. For example, the foamed spacer fluids may
comprise water, CKD, a foaming agent, an a gas. A foamed spacer fluid may be used, for
example, where it is desired for the spacer fluid to be lightweight In accordance w th present
embodiments, the spacer fluid may e used to displace a first fluid from a well bore with the
spacer fluid having a higher yield point than the first fluid. For example, the spacer fluid may be
used to displace at least a portion of a drilling fluid from the well bore. Other optional additives
may also be included in embodiments of the spacer fluids as desired for a particislar application,
For example, the spacer fluids may further comprise vi cosify g agents, organic polymers,
dispersants, surfactants, weighting agents, and any combination thereo
[00201 Th spacer fluids generally should have a density suitable for a particular
appHcation as desired by those of ordinary skill in the art, with. he benefit of this disclosure.
so e embodiments, the spacer fluids may have a density n the range of from about 4 pounds per
gallon ("ppg") to about 24 ppg. n other embodiments, the spacer fluids may have a density in
the range of abou 4 ppg to about ppg. In ye other embod tn ents, the spacer fluids may have a
density in the range of about ppg to about 3 ppg. Embodiments of the spacer fluids may be
foamed or unfoamed or comprise other means to reduce their densities known in the art, such as
lightweight additives. Those of ordinary skill in the art with the benefit of this disclosure, will
recognize the appropriate density for a particular application
[0021 ] The water used in an embodiment of the spacer fluids may include, for example,
freshwater, saltwater (e.g., water containing one or more salts dissolved therein), brine (e.g.,
saturated saltwater produced from subterranean formations), sea water, or any combination
thereof Generally, the water may be from any source, provided that the water does not contain
an excess of compounds that may undesirably affect other components in the spacer fluid. The
water is included in a amount sufficient to form a pampa e spacer fluid. In some embodiments,
the water may be included in the spacer fluids in an amount i the range of from about % to
about 95% b weight of the spacer fluid. n other embodiments, the water may be included in the
spacer fluids of ihe present Invention in an amount in the range of from about 25% to about 85%
by weight of the spacer fluid. On of ordinary skill in the art, w t the benefit of this disclosure,
will recognize the appropriate amount of water to include for a chosen application.
[0022] The CKD may be included in embodiments of the spacer fluids as rheoiog
modifier. Among other things, using CKD in embodiments of the present invention can provide
spacer fluids having rheoiogy suitable for a particular application. Desirable rheoiogy may be
advantageous to provide a spacer fluid that is effective for drilling fluid displacement, for
exa ple some instances, the CKD can be used to provide a spacer fluid with a ow degree of
thermal thinning. For example, the spacer fluid may eve have a yield point that increases at
elevated temperatures, such as those encountered dow hole
[0023] CKD is a material generated during the manufacture of cement that is commonly
referred to as cement kil dust. The term "CKD" is used herein to mean cement ki ln dust as
described herein and equivalent forms of cement kiln dust made in other ways. The term "CKD"
typically refers to a partially calcined kiln feed which cart be removed fro the gas stream and
collected, for example, in a dust collector during the manufacture of cement Usually, large
quantities of CKD are collected in the production of cement that re commonly disposed of as
waste. Disposal of the waste CKD can ad undesirable costs to the manufacture of the cement, as
we l the environmental concerns associated wit its disposal. Because the CKD is commonly
disposed as a waste material, spacer fluids prepared with CKD may be more economical than
conventional spacer fluids, which are commonly prepared with higher cost additives. Th
chemical analysis of CKD from various cement manufactures varies depending on a number of
factors, including the particu lar kiln feed, the efficiencies of the cement production operation, and
the associated dust collection systems. CKD generally may comprise a variety of oxides, such as
SiOj, A.I 2O3, Fe 0 C aC MgO, S ) , a , and K 0 .
[0024] CKD may b inc ded i the spacer f ids in an amount sufficient to provide,
for example, the desired theological properties. o some embodiments, the CKD may be present
in the spacer fluids in an amount in the range of from about 1% to about 65% by weight of the
spacer fluid (e.g., about 1%, about 5%, about 10%, about %, about 20%, about 25%, about
30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, etc.).
n some embodiments, the CKD may be present in the spacer fluids in an amou t in the range of
from about 5% to about 60% by weight of the spacer fluid. In some embodiments, the CKD may
be present in an amount in the range of from about 20% to about 35% by weight of the spacer
fluid. Alternatively, the amount of CKD may be expressed by weight of dry solids. As used
herein, the term "by weight dry solids" refers to the amount of a component, such as CKD,
relative to the overall amount of dry solids used in preparation of the spacer fluid. Fo example,
the CKD may be present in an amount in a range of from about 1% to 100% by weight of dry
solids (e.g., about 1%, about 5%, about %, about 20%, about 30%, about 40%, about 50%,
about 60%, about 70%, about 80%. about 90%, 100%, etc.). In some embodiments, the CKD
may be present in an amount in the range of from about 50% to 100% and, alternatively, from
about 80% to 0% by weight of dry solids. On of ordinary skill in the art, with the benefit of
this disclosure will recognize the appropriate amount of CKD to include for a chosen application.
[0025] While the preceding description describes CKD, the present invention is broad
enough to encompass the use of other part ially calcined kiln feeds. For example, embodiments of
the spacer fluids may comprise me kiln dust, which is a material that is generated during the
manufacture of lime. The term time kiln dust typically refers to a partially calcined kiln feed
which can be .removed from the gas stream and collected, for example, in. a dust collector during
the manufacture of lime The chemical analysis of lime kiln dust from various lime
manufacturers varies depending on a number of factors, including the particular limestone or
dolomitic limestone fe , the type of kiln, the mode of operation of the kil , the efficiencies of
the lime production operation, and the associated dust collection systems. Lime kiln dust
generally may comprise varying amounts of free lime and free magnesium, lime stone, and/or
dolomitic limestone a d a variety of oxides, such as S i¾ O , CaO, g a
and 0 , and other components, such as chlorides.
[0026] Optionally, embodiments of the spacer fluids may further comprise fly ash A
variet of fl ashes may be suitable, including fly classifi ed as Class C or Class F f y ash
according to American Petroleum institute, AM Specification for Materials and Testing for We !
Cements, API Specification 10, Fifth Ed., Ju y , 990 Suitable examples of fly ash include, but
ar not limited to, P ZMIX A cement additive, commercially available from Halliburton
Energy Services, inc., Duncan, Oklahoma Where used, the fly ash generally may be included in
th spacer fluids in an amount desired for a particular application. In some embodiments, the fly
ash may be present i th spacer fluids in a amount n th range of from about % to about 60%
by weight of the spacer fluid (e.g., about 5%, about 10%, about 5%, about 20%, about 25%,
about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, etc.). n so e
embodiments, the f y ash may be present in the spacer fluids in an amount in the range of from
about % to about 35% by weight of the spacer fluid. In some embodiments, the fly ash may be
present in the spacer fluids in an amount in the range of from about 1% to about 10% by weight
of the spacer fluid. Alternatively, the amount of f y ash may be expressed by weight of dry
solids. For example, the fly ash may e present in an amount n range of from about 1% to
about 99% by weight of dry sol ids (e.g., about 1%, about 5%. about 10%, about 20%, about 30%,
about 40%, about 50%, about. 60%, about 70%, about 80%, about 90%, about 99%, etc.). n
some embodiments, the fly ash may be present i an amount in the range of from about 1% to
about 20% and, alternatively, from about 1% to about 10% by weight of dry solids. One of
ordinary skill in the art, with the benefit of this disclosure, will recognise the appropriate amount
of the f y ash to include for a chosen application.
[0027] Optionally, embodiments of the spacer fluids may further comprise barite. In
some embodiments, the barite ay be sized barite. Sized barite generally refers to barite tha has
been separated, sieved, ground, or otherwise sized to produce barite having a desired particle size.
For example, the barite may be sized to produce barite having a particle size less than about 200
microns in size. Where used, the barite generally may be included in. the spacer fluids in an
amount desired for a particular application. In some embodiments, the barite may be present in
the spacer fluids in an amount in the range of from about 1% to about 60% by weight of the
consolidating spacer fluid (e.g., about 5%, about %, about %, about 20%, about 25%, about
30%, about 35%, about 40%, about 45%, about 50% about 55%, etc.). In some embodiments,
the barite may be present in the spacer fluids in an amount in the range of from about 1% to about
35% by weight of the spacer fluid. n some embodiments, the barite may be present in the spacer
fluids i an amount in the range of fro about % to about 10% by weight of the spacer fluid.
Alternatively, the amount of barite ma be expressed by weight of dry solids. For example, the
ba te may be present in an amount in a range of from about 1% to about 99% by weight of dry
solids (e.g., about %, about 5%, about 10%, about 20%, about 30%, about 40%, about 50%,
about 60% about 70%, about 80%, about 90%, abou 99%, etc.), n some embodiments, the
bariie ma be present in an amount in the range of from about 1% to about. 20% and,
alternatively, fro ru about 1% to about % b weight of dry solids. One of ordinary skil l in the
art. with the benefit of this disclosure, will recognize the. appropriate amount of the barite to
include for a chosen application.
[0028] Optionally, embodiments of the spacer fluids may further comprise pumicite.
Where used, the pumicite generally may be included in the spacer fluids in a amount desired for
a particular application, n some embodiments, the pumicke may be present in the spacer fluids
in an amount in the range of from about 1% to about 60% by weight of the spacer fluid (e.g.,
about 5%, about %, about %, about 20%, about 25%, about 30%, about 35%, about 40%,
about 45%, about 50% about 55%, etc.). In some embodiments, the pumicite may be present i
the spacer fluids n an amount in the range of from about i% to about 35% by weight of the
spacer fluid, n some embodiments, the pumicite may be present in the spacer fluids in a
amoun in the range of from about !% to about 10% by weight of the spacer fluid. Alternatively,
the amount of pumicite may be expressed by weight of dry solids. For example, the pumicite
may be present n an amount in a range of from about .1% to about 99% by weight of dry solids
(e.g., about 1%, about 5%, about %, about 20%, about 30%, about 40%, about 50%, about
60%, about 70%, about 80%, about 90%, about 99%, etc.). In some embodiments, the pumicite
may be present in an amount in the range of from about 1% to about 20% and, alternatively, fr o
about .1% to about . % by weight of dry solids. One of ordinary skill i the art, with the benefit
of this disclosure, wil recognize the appropriate amount of the pumicite to include for a chosen
application.
[0029] Optionally, embodiments o f the spacer fluids may further comprise .a free water
control additive. As used herein, the term "free water control additive" refers to an additive
included in a liquid for, among other things, reducing (or preventing) the presence of free water
in the liquid. Free water eonirol additive may also reduce (or prevent) the settling of solids.
Examples of suitable free water control additives include, but are not limited to, bentonite,
amorphous silica, hydroxye hy cellulose, and combinations thereof An example of suitable
fre water control additive is SA- suspending agent, available from Halliburton Energy
Services, nc. Another example of a suitable free water control additive is WG- solid
additive, available from Halliburton Energy Services, nc. The free water control additive may be
provided as a dry solid in some embodiments. Where used, the free water control additive ma
be present i an amount in the range of from about 0.1% to about 1.6% by weight o f dry solids,
for example, n alternative embodiments, the free water control additive may be prese t in an
amount in the range of from about 0.1% to about 2% by weight of dry solids.
[0030] i some embodiments, the spacer fluids may further comprise a lightweight
additive. The lightweight additive may be included to reduce the density of embodiments of th
spacer fluids. or example, the lightweight additive may be used to form a lightweight: spacer
fluid, for example, having a density of less tha about 3 ppg. The lightweight additive typically
may have a specific gravity of less than abou 2,0. Examples of suitable lightweight additives
may include sodium silicate, hollow microspheres, gilsonite, perlite, and combinations thereof
An example of a suitable sodium silicate s EC TE additive, available from Halliburton
Energy Services, nc. Where used, the lightweight additive may be present in an amount in the
range of from about 0.1 % to about 20% by weight of dry solids, for example. n alternative
embodiments, the lightweight additive may be present in an amount in the range of from about
1% to about % by weight of dry solids.
[00 ] As previously mentioned, embodiments of the spacer fluids may be foamed with a
gas, for example, to provide a spacer fluid with a reduced density, t should be understood that
reduced densities may be needed for embodiments of the spacer fluids to more approximately
match the density of a particular drilling fluid, for example, where ightwe ig ht. dril ling fluids are
being used. A drilling fluid ma be considered lightweight if it has a density of less than about
13 ppg, alternatively, less than about 0 ppg, and. alternatively less than about 9 ppg. n some
embodiments, the spacer fluid may be foamed to have a density within about % of the density
of the drilling fluid and, alternatively, within about 5% of the density of the drilling fluid. While
techniques, such as lightweight additives, may be used to reduce the density of the spacer fluids
comprising C D without .foaming, these techniques may have drawbacks. For example,
reduction of the spacer fluid's density to below about .13 ppg using lightweight additives may
produce unstable slurries, which can have problems with settling of solids, floating of lightweight
additives, and free water, among others. Accordingly, the spacer fluid may be foamed to provide
a spacer fluid having a reduced density that is more stable.
[0032] Therefore, in some embodiments, the spacer fl uid may be foamed and comprise
water, CKD, a foaming agent, and a gas Optionally, to provide a spacer fluid with a lower
density and more stable foam, the foamed spacer fluid may further comprise a lightweight
additive, for example. With the lightweight additive, a bas slurr may be prepared thai may the n
be foamed to provide an even lower density. I some embodiments, the foamed spacer -fluid ay
have a density in the range of from about 4 ppg to about 3 pp d, alternatively, about 7 ppg t
about 9 ppg. n one particular embodiment, a base slurry may be foamed from a density of i the
range of from about 9 ppg to about . ppg to a lower density, for example, in a range of from
about 7 ppg to about 9 ppg
[0033] The gas used in embodiments of the foamed spacer fluids may be any suitable gas
for foaming the spacer fluid, including, but not limited to air, nitrogen, and combinations thereof.
Generally, the gas should be present in embodiments of the foamed spacer fluids in a n amount
sufficient t form the desired foam. n certain embodiments, the gas may be present in an amount
in the range of from about 5% to about 80% by volume of the foamed spacer fluid at atmospheric
pressure, alternatively, about 5% to about 55% by volume, and, alternatively, about 5% to about
30% by volume.
[0034] Where foamed, embodiments of the spacer fluids may comprise a foaming agent
for providing a suitable foam. As used herein, the term "foaming agent'* refers to a material or
combination of materials that faci tate the formation of a foam i a liquid. A y suitable foaming
agent for forming a foa in an aqueous liquid may be used in embodiments of the spacer fluids.
Examples of suitable foaming agents may include, bu are not limited to: mixtures of a
ammonium salt of an alky ether sulfate, a cocoamidopropyl betaine surfactant, a
cocoamidopropyl dtmethylamine oxide surfactant, sodium chloride, and water; mixtures of an
ammonium salt of an alky! ether sulfate surfactant, a cocoamidopropyl y ro xys aine
surfactant, a cocoamidopropyl dimeraylamine oxide surfactant, sodium chloride, and water;
hydro lyi .ed keratin; mixtures of an ethoxy!ated alcohol ethe sulfate surfactant, a alky! or aikene
amidopropyl betaine surfactant, and an aiky or aikene dim thyla ne oxide surfactant; aqueous
solutions of an alpha-olefmic sulfonate surfactant a d betaine surfactant; and combinations
thereof. An example of a suitable foaming agent is FOA ER™ 760 foamer/stabilizer, available
from Halliburton Energy Services, nc. Suitable foaming agents are described in U.S. Patent s.
6,797,054, 6,547,871 , 6,367,550, 6,063,738, and 5,897,699, th entire disclosures of which re
incorporated herein by reference
[0035] Generally, the foaming agent may be present in embodiments of the foamed
spacer fluids in an amount sufficient t provide a suitable foam. In some embodiments, the
foaming agent may be present in an amount in the range o f from about 0.8% to about 5% by
volume of the water ( bvo ).
[0036] A wide variety of additional additives may be included in the spacer fluids as
deemed appropriate b one skilled in the art, with the benefit o f this disclosure. Examples of
such additives include, but are not limited to: supplementary cementitious materials, weighting
agents, viseosifying agents (e.g., clays, hydratab le polymers, g ar gum), fluid loss control
additives, lost circulation materials, filtration control additives, disps rsa.nts. detoamers, corrosion
inhibitors, scale inhibitors, formation conditioning agents, and a water-welting surfactants,
Water-wetting surfactants may be used to aid in removal of oil from surfaces in the well bore
(e.g., the casing) to enhance cement and consolidating spacer fluid bonding. Examples of
suitable weighting agents include, tor example, materials having a specific gravity o 3 or greater,
such as barite. Specific examples of these, and other, additives include-: organic polymers,
biopolymers, .latex, ground rubber, surfactants, crystalline silica, amorphous silica, silica flour,
fumed silica, nano-clays (e.g., clays having at least one dimension less than 00 n ) salts, fibers,
hydratabie clays, microspheres, rice husk ash, micro-fine cement (e.g., cement having an average
particle size of from about. 5 microns to about 0 microns), me akaolin, zeolite, shale, Portland
cement, Portland cement interground with pumice, perlite, barite, slag, lime (e.g., hydrafed lime),
gypsum, and any combinations thereof, a d the like n so e embodiments, a supplementary
cementitious material may be included in the spacer .fluid in addition to or i place of all or a
portion of the C D. Examples of suitable supplementary cementitious materials include, without
limitation, Portland cement, Portland cement interground with pumice, miero-fine cement * fly
ash, slag, pumieite, gypsum and any combination thereof. A person having ordinary skill in the
art, with the benefit of this disclosure, will readily be able to determine the typ and amount of
additive useful for a particular application and desired result,
[0037] As previously mentioned, embodiments of the spacer fluids may be consolidating
in that the spacer fluids may develop gel strength and/or compressive strength in the well bore.
Consolidation is defined herein as one of three types of material behavior: Type 1consolidation is
identifiable as a gelled fluid that can be moved and/or pumped when the hydraulic shear stress
exceeds the yield point (YP of the gel. Type 2 consolidation is identifiable as a plastic semi-solid
that can experience "plastic deformation" if the shear stress, compressive stress, or tensile stress
exceeds the ''plastic yield limit." Type 3 consolidation s identifiable as a rigid solid similar to
regular set cement During a steady progressive strain rate during conventional compressive
testing, both confi ned and unconfmed, a Type 3 consolidated material would exhibit linear elastic
Hookean stress-strain behavior, followed by some plastic yield and/or mechanical failure. This
novel consolidating spacer fluid may transform from the pumpabie fluid thai was placed during
the normal displacement operation to Type 1 and/or further progress to Type 2 and/or further
progress to Type 3. i t should be understood tha the consolidation of the spacer fluid is at well
bore conditions and, as wil be appreciated b those of ordinary skill in the art, well bore
may vary. However, embodiments of the spacer fluids may be characterized by
exhibiting Type , Type 2. or Type 3 consolidation under specific well bore conditions,
[0038] Specific examples of how to characterize a Type 1 consolidation include
measuring the yield stress. Type i consolidation exhibits a YP fro about 25 Pascals to about
250 Pascals, where YP i measured y one of the methods described in. U.S. Patent No.
6,874,353, namely; using a series of parallel vertical blades on a rotor shaft, referred to by those
skilled in the art as the "Vane Method"; or using the new device and method also described i
U.S. Patent No. 6,874,353, Another method used to define the YP of Type 1 consolidation is
defined in Morgan, R.G., Suter, D.A., and Sweat, V.A., Mathematical Analysis of a Simple Back
x r k Rheometer, ASAE Paper No. 79-6001. Additionally, other methods commonly known
to those skilled in the art ay be used to define the YP of T pe 1 consolidated spacer fluids.
Alternatively, another method of characterizing a Type I consolidation includes measuring the
gelled strength of the material, which may be defined as "Static Gel Strength" SGS as is defined
and measured in accordance with the AP Recommended Practice on. Determining the Static Get
Strength of Cement Formations, ANSI/API: Recommended Practice B-6. A Type 1
consolidation may exhibit SGS values rom about 70 1 f/ OG ft2 up to about 500 b / fr.
[0039] Specific examples of ho to characterize a Type 2 consolidation include
measuring the yield limit in compression (YL~C), The YL-C is simply the uniaxial compressive
stress at which the material experiences a permanent deformation. Permanent deformation refers
to a measurable deformation strain that does not return to zero over a period of time that is o the
same order of magnitude as the total time required to conduct the measurement, -C may range
from 1 p s i (ib 'sq.in.) to 2,000 psi, with the most common values ranging from 5 psi to 5 0 psi.
[0040] Specific examples of how to characterize a Type 3 consolidation include
measuring the compressive strength. Type 3 consolidation will exhibit unconfined uniaxial
compressive strengths ranging fro about 5 psi to about 10 ,000 psi, while the most common
values wil range from about 10 psi to abou 2,500 psi. These values are achieved in 7 days or
less, So e formulations ay be designed so as to provide significant compressive strengths with
24 hours to 48 hours. Typical sample geometry and sizes for measurement are similar to, but not
limited to, those used for characterizing oil well cements: 2 inch cubes; or 2 inch diameter
cylinders that are 4 inches in length; or 1 inch diameter cylinders that are inches in length; and
other methods known to those skilled n the art of measuring "mechanical properties" of oi! well
cements. For example, the compressive strength may be determined by crushing the samples in a
compression-testing machine. The compressive strength is calculated from the failure load
divided by the cross-sectional area resisting the loa and is reported in units of pound- orce per
square inch (psi). Compressive strengths may be determined n accordance with API! P 8 -2,
Recommended Practice for Testing Well Cements, First Edition, July 2005.
[0041] As a specific example of a consolidation, when left in a well bore annulus ( g ,
between a subterranean formation and the pipe string disposed i the subterranean formation or
between the pipe strin and a larger conduit disposed in the subterranean formation), the spacer
fluid may consolidate to develop static gel strength and or compressive strength. Th
consolidated mass formed in the well bore annulus act to support and position the pipe string
in the ell bore and bond the exterior surface of the pipe string to the walls of the well bore or to
th larger conduit. The consolidated ass formed in the we l bore annulus ay also provide a
substantially impermeable barrier to seal off formation fluids and gases and consequently also
serve to mitigate potential fluid migration. The consolidated ass formed in the well bore
annulus ma also protect the p pe string or other conduit from corrosion.
[0042] Embodiments of the spacer fluids of the present inventon may have a transition
ti e that is shorter than the transition time of cement compositions subsequently introduced into
the well bore. Th term tra sition ti e " as used herein, refers to the time for f id to progress
from a static ge strength of about 100 Ibf ft 2 to about 500 bf 00 By having a shorter
transition time, the consolidating spacer fluid can reduce or eve prevent migration of gas in the
well bore, even if gas migrates through a subsequently introduced cement composition before it
has developed sufficient gel strength to prevent such migration. Gas and liquid migration can
typically be prevented at a static gel strength of 500 f 0 t2. By reducing the amount of gas
that can migrate through the well bore, the subsequently added cement compositions can progress
through its slower transition period without gas migration being as significant factor as the
cement develops static ¾e strength. Some embodiments of the consolidating spacer fluids mav
have a transition time (i.e., the time to progress from a static gel strength of about 0 bf/ 0
to about 500 lbf/100 ft) at well bore conditions of about 45 minutes or less, about 30 minutes or
less, about 20 minutes or less, or about 10 minutes or less. Embodiments of the consolidating
spacer fluids also quickly develop static gel strengths of about 100 lbf/100 ft 2 and about 50
b ' l O ft , respectively, at well bore conditions. The time for a fluid to a develop a static gel
strength o about 0 Sbf/100 ft is also referred to as the "zero gel time." For example, the
consolidating spacer fluids may have a zero gel time at well bore condition of about 8 hours or
less, and. alternatively, about 4 hours or less. In some embodiments, the conso at g spacer
fluids may have a zero gel time i a range of from about 0 minutes to about 4 hours or longer. By
way of further example, the consolidating spacer fluids may develop static gel strengths of about
500 lbf/ 0 ft or more at well bore conditions in a time of fr o about 0 minutes to about 8
hours or longer. The preceding time for development of static strengths are listed as being at
we l bore conditions. Those of d skill in the ar w ll understand that particular wel bor
conditions (e.g., temperature, pressure, depth, etc.) will vary; however, embodiments o f the
spacer should meet these specific requirements at well bore conditions. Static gel strength may
be measured in accordance with AP Recommended Practice on Determining- the Static Gel
Strength of Cement Formations. .ANSI/API Recommended Practice B-6
[0043] Embodiments o the spacer fluids of the present invention may be prepared in
accordance with suitable technique. In some embodiments, the desired quantity of water may
be introduced into a ixer (e.g., a cement blender) followed by the dry blend. The dry blend ay
comprise the CK. and additional solid additives, for example, Additional liquid additives, if
a y, may be added to the water a desired prior to, or after, combination with the dry blend. This
mixture may be agitated for a sufficient period of time to form a base slurry. This base slurry
may then be introduced into th we l bore via pumps, for example. n the foamed embodiments,
the base s rry may be pumped into the well bore, and a foaming agent ay be metered into the
base slurry followed by injection of a gas, e.g., at a foam mixing T in an amount sufficient to
foam the base slurry thereby forming a foamed spacer fluid, in accordance with embodiments of
the present invention. After foaming, the foame -spacer fluid may be introduced into a well bore.
As will be appreciated by those of ordinary skill in the art, with the benefit of this disclosure,
other suitable techniques for preparing spacer fluid may be used in accordance with
embodiments of the present invention:.
[0044] An example method of the present invention includes a method for evaluating a
spacer fluid. The example method may comprise providing the space fluid for use in separating
a drilling fluid and a cement composition in a well bore. Properti es of the spacer fluid may the
be. measured to determine, .for example, the consolidation efficiency for the particular fluid. In
some embodiments, the transition time and/or zero ge time of the spacer fluid may be measured.
As previously described, the transition time is the time for the fluid to progress from a static gel
strength of about 100 ibf OO ft 3 to about 500 lbf Ί 00 ft , and the zero gel time is t e time for the
fluid to develop a static gel strength of about 1 0 Ib Oft 2. Static ge strength may be measured
in accordance with AH Recommended Practice on Determining the Static Gel Strength of
Cement Formations, ANSI/API Recommended Practice ! -6. In some embodiments, the
compressive strength may be measured, which may be the uneonfined uniaxial compressive
strength. Techniques for testing of compressive strength testing are described in ore detai
above. These measurements may be performed at a range of conditions, for example, to simulate
well bore conditions. n some embodiments, the transition time may be measured at a
temperature of from about 4{ to about 30 ' and a pressure of from abou 2,0 psi to about
,000 psi. The compressive strengths may be determined, for example, at atmospheric
conditions after the spacer fluid has been allowed to set in a water bath at temperatures of from
about 40ft F to 30 F for a t me of iron* about 24 hours to about 7 days. n some embodiments,
the preceding evaluation ma be performed for a set of sample spacer fluids, wherein
embodiments further comprises selecting one of the sample spacer fluids from the set based o
the measured properties. Embodiments may .further comprise preparing spacer fluid based on
the selected spacer fluid and using the prepared spacer fluid in displacement of a drilling fluid
from a we bore annul us.
[0045] A . example method of the present invention includes a method of enhancing
rheological properties of a spacer fluid. The method ay comprise including CKD in a spacer
fluid. The CKD may be included in the spacer fluid in an amou t sufficient to provide a higher
yield point than a first fluid. The higher yield poi t may be desirable, for example, to effectively
displace the first fluid from the well bore. As used herein, the term "yield point" refers to the
resistance of a fluid to initial flow, o representing the stress required to start fluid movement. n
an embodiment, the yield point of the spacer fluid at temperature of up to about 0 'F is greater
than about 5 lb/ 00 ft n a embodiment, the yield point of the spacer fl ui at a temperature of
up to iibout 0 F is greater than about 0 / 00 f , n an embodiment, the yield point o f the
spacer fluid at a temperature of up to about S0' F s greater than about 20 lb/1 0 ft , t may be
desirable for the spacer fluid to not thermally thin to a yield point below the first fluid at elevated
temperatures. Accordingly, the spacer fluid may have a higher yield point than the first fluid at
elevated temperatures, such as 0 F or bottom hole static temperature 'B ST' . n one
embodiment, the spacer fluid may have a yield point that increases at elevated temperatures. For
example, the spacer fluid may have a yield point that is higher at 1.80° F than at 80°F. By way of
further example. The spacer fluid may have a yield point that is higher at BUST than at 80°F.
[0046] Another example method of the present invention includes a method of displacing
a first fluid fro a well bore, the well bore penetrating a subterranean formation. The method
may comprise providing a spacer fluid that comprises CKD and water. The method may further
comprise introducing the spacer fluid into the well bore to displace at least a portion of the first
fluid from the well bore. n some embodiments, the space fluid may displace the first fluid from
a well bore annulus such as the anrtu!us between a pipe string and the subterranean formation or
between the pipe string and a larger conduit. In some embodiments, the spacer fluid may he
characterized by having a higher yield point than the first fluid at SOT. n some embodiments,
the spacer fluid may be characterized by having a higher yield point than the first fluid at 0*1 .
1 5
In some embodiments, the spacer fluid may be characterized by having a higher yield point than
the first fluid at S8
[0047] n an embodiment, the first fluid displaced by the spacer fluid comprises a drilling
.fluid. By way of example, the spacer fluid may be used to displace the drilling fluid from the
wel bore i addition to displacement of the drilling fluid from the well bore, the spacer fluid
may also remove the drilling fluid from the walls of the well bore. The drilling fluid ay
include, for example, a y number of fluids, such as solid suspensions, mixtures, and emulsions
in some embodiments, the drilling fluid may comprise an oil-based drilling fluid. An example of
a suitable oil-based drilling fluid comprises an invert emulsion. In some embodiments, the oilbased
drilling fluid may comprise an oleaginous fluid. Examples of suitable oleaginous fluids
that may be included in the oil-based drilling fluids include, but are ot limited to, a-o!efras,
internal olefins, alkanes, aromatic solvents, cycloalkanes, liquefied petroleum gas, kerosene,
diesei oils, crude oils, ga oils, fuel oils, paraffin oils, mineral oils, l w t xieiiy mineral oils,
olefins, esters, amides, synthetic oils (e.g., poiy fins), polydiorganosiloxanes, siioxanes,
organosiloxanes, ethers, acetaSs, diaikylcarbonates, hydrocarbons, and combinations thereof.
Additional steps in embodiments of the method may comprise introducing a pipe string into t e
wel bore, introducing a cement composition into the well bore with the spacer flui separating
the cement composition and th first fluid in an embodiment, the cement composition may be
allowed to set in the well bore. The cement composition may include, for example, cement and
water
[0048] Another example method of the present invention includes a method of separating
fluids in a well bore, the well bore penetrating a subterranean formation. The method ma
comprise introducing a spacer fluid into the well bore, the well bore having a first fluid disposed
therein. The spacer fluid may comprise, for example, C D and water. The method may further
comprise introducing a second fluid into the well bor with the spacer fluid separating the first
fluid and the second fluid in an embodiment, the first fluid comprises a drilling fluid and th
second fluid comprises a cement composition. By way of example, the spacer fluid may prevent
the cement composition from contacting the drilling fluid. The cement composition may be
foamed or unfba ed as desired for a particular application. n an embodiment, the cement
composition comprises cement kiln dust, water, and optionally a hydraulic c mentit ous material.
A variety of hydraulic cements may be utilized in accordance with the present invention,
including, but not limited to, those comprising calcium, aluminum, silicon, oxygen, iron, and/or
sulfur, which set and harden by reaction with water. Suitable hydraulic cements include, but are
not limited to, Portland cements, pozzoiana cements, gypsum cements, high alumina content
cements, slag cements, silica cements, and combinations thereof, i certain embodiments, the
hydraulic cement m comprise a Portland cement, some embodiments, the Portland cements
that arc suited for use in the present invention are classified as Classes A, C , and G cements
accordin to American Petroleum Institute, API Specification for Materials and Testing for Well
Cements, API Specification 10, Fifth Ed., Jul. ! . 1990. The spacer fluid may also remove the
drilling fluid, dehydrated/gel led drilling fluid, and/or filter cake solids from the well bore i
advance of the cement composition. Embodiments of the spacer fluid may improve the efficiency
of the removal of these and other compositions from: the we l bore. Removal of these
compositions fro the well bore may enhance bonding of the cement composition to surfaces in
the well bore, in an additional embodiment, at least a portion of used and or unused CKD
containing spacer fluid are included in the cement composition that is placed into the we l and
allowed to set
[0049] n so embodiments, at least a portion o f the spacer fluid ma he left in the well
bore such that the spacer fluid consolidates in the wel bore, in some embodiments, the spacer
fluid may consolidate to form an annular sheath of a rigid solid. The annular sheath of may bond
the exterior surface of the pipe string to the walls of the well bore or to the larger conduit. An
example, method of the present invention may further include measuring the consolidation of the
spacer fluid. This measurement may also include a measurement of the integrity of the bond
formed between the consolidated spacer fluid and the exterior wall of the pipe string and/or
between the consolidated spacer fluid and the formation or larger conduit disposed in the well
bore, in some embodiments, data may be collected corresponding to the integrity of this bond,
and the data may be recorded on a log, commonly referred to as a "bond long." The bond log
may be used to. for example, analyze the consolidation properties of the spacer fluid in the well
bore. Accordingly, embodiments may include running cement bond log on at least the portion
of the well bore containing the consolidated spacer fluid. The cement bond log tor the settable
spacer fluid may be obtained by any method used to measure cement integrity without limitation.
some embodiments, a tool may be run into the well bore on a wireline that can detect the bond
of the set spacer fluid to the pipe string and/or the formation (or larger conduit). An example of a
suitable too includes a sonic tool.
[0050] To facilitate a better understanding o f the present invention, the following
examples of certain aspects of some embodiments are given. In no way should the following
examples be read to limit, or define, the scope of the invention. In the following examples,
concentrations are given in weight percent of the overall composition.
EXAMPLE 1
[005 Sample spacer fluids were prepared to evaluate the theological properties of
spacer fluids containing C D. The sample spacer fluids were prepared as follows. First, all dry
components (e.g., C D, fly ash, ben o it FWCA, etc.) were weighed nto a glass container
having a clean lid and agitated by hand until blended. Tap water was then weighed into a Waring
blender jar. The dry components were then mixed into the water with 4,000 rpm stirring. The
blender speed was then increased to ,000 rpm for about 35 seconds.
[0052] Sample Spacer Fluid No. 1 was an poun per gallon slurry that comprised
60.62% water, 34.17% CKD, 4.63% fly ash, and 0.58% free water control additive (WG
solid additive).
[0053] Sample Spacer Fluid No. 2 was an pound per gallon slurry that comprised
60.79% water, 30.42% CKD, 4,13% fl ash, 0. % free water control additive (WG- solid
additive), 3,45% bento i e, and 1.04% Econo te' additive,
[0054] Rh ol gicai values were then determined using a Fann Mode l 35 Viscometer.
Dial readings were recorded a speeds of 3, 6, 100, 200, and 300 with a bob, a n R rotor, and
a 1.0 spring. Th dial readings, plastic viscosity, and yield points for the spacer fluids were
measured in accordance with API Recommended Practices B, Bingham plastic model and are
set forth in the table below. The abbreviation PV refers to plastic viscosity, while the
abbreviation "VP" refers to yield point.
TABLE 1
[0055] The thickening time of the Sample Spacer Fluid No 1 was also determined in
accordance with API Recommended Practice B at 205" F. Sample Spacer Fluid No. 1 had a
thickening time of more than 6:00+ hours.
[0056] Accordingly, the above example illustrates that the addition of CK to a spacer
fluid may provide suitable properties fo r use in subterranean applications. In particular, the
above example illustrates, inter alia, that CKD may be used to provide a spacer fluid that may not
exhibit thermal thinning with the spacer fluid potentially even having a yield point that increases
with temperature. For example, Sample Spacer Fluid No. 2 had a higher yield point at 0° F
than a F. In addition, the yield point of Sample Spacer Fluid No. I had only a slight
decrease at 0° F as compared to 80° F. Even further, the example illustrates that addition of
CKD to spacer fluid may provide a plastic viscosity that increases with temperature.
EXAMPLE 2
05 Additional sample spacer Ouids were prepared to rt her evaluate the rheological
properties of spacer fluids containing CKD. The sample spacer fluids were prepared as follows.
First, a l dry components (e.g., CKD, l ash) were weighed into a glass container having a clean
id and agitated by hand until blended. Tap water was then weighed into a Waring blender jar.
The dry components were then mixed into the water with 4,000 rpm stirring. The blender speed
was then increased to 000 rpm for about 35 seconds..
[0058] Sample Fluid No, 3 was a 12 .5 pound per gallon fluid that comprised 47.29%
water and 52. % CKD.
[0059 Sample Fluid No. 4 was a 12.5 pound per gallon fluid that comprised 46.47%
water, 40. 5% CKD, and .38% fly ash.
[0060] Sample Fluid No. 5 was a 2.5 pound per gallon fluid that comprised 45,62%
water, 27.19% C , and 27, 9% fly ash.
[0061] Sample Fluid No, was a 12 .5 pound per gallon fluid that comprised 44.75%
water. . . ¾ C D, a d ,44% fly ash.
[0062] Sample Fluid No. 7 (comparative) was a .5 pound per gallon fluid that
comprised 43.85% water,. and 56.15% fly ash.
[0063] Rheological values were then determined using a Fann Model 35 Viscometer,
Dial readings were recorded at speeds of 3, 6, 30, 60, 100, 200, 300, and 600 with a bob, an
R rotor, and a 1.0 spring. The dial readings, plastic viscosity, and yield points for the spacer
fluids were measured in accordance with API Recommended Practices , Bingham plastic
model and are set forth in the table below. The abbreviation "PV" refers to plastic viscosity,
while the abbreviation refers to yield point.
TABLE 2
[0064] Accordingly, the above exa ple illustrates that the addition of CK to a spacer
fluid may provide suitable properties for use n subterranean applications. n particular, the
above example illustrates, inter alia, that CKD ma be used to provide a spacer fluid that may t
exhibit thermal thinning with the spacer fluid potentially even having a yield point that increases
with teniperiiture. n addition, as illustrated in Table 2 above, higher yield points were observed
for spacer fluids with higher concentrations of CKD.
EXAMPLE 3
[0065] A sample spacer fluid containing CKD was prepared to compare the rheoiogieal
properties of spacer fluid containing CKD with an oil-based drilling fluid. The sample spacer
fluid was prepared a follows. First, all dry components (e.g., CKD, fly ash, b to it , etc.) were
weighed into a glas container having a clean lid and agitated by hand until blended. Tap water
was then weighed nto a Waring blender jar. The dry components were then mixed into the water
with 4,000 rp stirring. The blender speed was then increased to J2,000 rpm for about 35
seconds
[0066] Sample Spacer Fluid No. S was an 1 pound per gallon slurry that comprised
60,79% water, 30.42% CKD, 4.13% fly ash, 0.17% free water control additive (WO- 7 solid
additive), 3,45% bentonite, and 1.04% .Ec n lite additive
[0067] The oil-based drilling fl ui was a 9 pound pe gallon oil-based mu .
0 6 8 Rheological values were then determined using a Fann Model 35 Viscometer
D a readings were recorded at speeds of 3 6, D , 200, and 300 with a bob, an rotor, and
a .0 spring. The dial readings, plastic viscosity, and yield points for the spacer fluid and drilling
fluid were measured in accordance with AP Recommended Practices B Bingham plastic
model and are set forth in the table below. The abbreviation PV refers to plastic viscosity,
while the abbreviation YP refers to yieid point The abbreviation "OBM" refers to oil-based
mud.
[0069] Accordingly, the above example illustrates that the addition of CKD to a spacer
fluid ma provide suitable properties for use in subterranean applications. In particular, the
above example illustrates, inter alia, that CKD may be used to provide a spacer fluid with a yield
point that is greater than a drilling fluid even at elevated temperatures. For example. Sample
Spacer Fluid No 8 has a higher yield point at 80° F than the oil-based ud.
EXAMPLE 4
[0070] A foamed spacer fluid (Sample Fluid 9) was prepared that comprised CKD, First,
a base slurry was prepared that had a density of 10 ppg and comprised CKD, a free water control
additive (0.7% by weight of CKD), a lightweight additive (4% by weight of CKD), and fresh
water (32.16 gallons per 94-pou.nd sack of CKD). The free water control additive was SA-
™ suspending aid The lightweight additive was EC NO TE additive. Next, a foaming
agent (FOA E 760 amer stab l er) in an amount of 2% bvow was added, and the base
slurry was then mixed in a foam blending jar for 4 seconds at ,000 rpm. The re sulting foamed
spacer fluid had a density of 8.4 ppg The " of the resultant foamed spacer fluid was then
measured using a free fluid test procedure as specified in AP Recommended Practice 10B.
However, rathe than measuring the free fluid, the amount of "sink" was measured after the
foamed spacer fluid remained static for a period of 2 hours. The foamed spacer fluid was initially
at 200° and cooled to ambient temperature over the 2-hour period. The measured sink for this
a ed spacer fluid was 5 millimeters.
EXAMPLE 5
[0 0 Another foamed spacer fluid (Sample Fluid 1.0) was prepared C a t comprised
CKD. First, a base slurry was prepared that had a density of 0.5 ppg a d comprised CKD, a free
water control additive (0.6% by weight of CKD), a lightweight additive (4% by weight of CKD),
and fresh water (23.7 gallons per 94~pound sack of CKD). The free water control additive was
SA- suspending aid The lightweight additive was ECO LiTE additive. Next, a
foaming agent (a hexylene glyeoi/eoeobetaine blended surfactant) n a a oun of 2% bvow was
added, and the base slurry was then mixed in a foam bSending jar for 6 seconds at 12,000 rp
The resulting foamed spacer fluid had a density of 8.304 ppg The resultant foamed spacer fluid
had a sink of 0 millimeters, measured as described above for Example 4
EXAMPLE
[0072] Th following series of tests were performed to determine the compressive
strength of consolidating spacer fluids. Twenty-two samples, labeled sample fluids 11-32 in the
table .below, were prepared having a density of 12.5 ppg using various concentrations o f
additives. The amount o f these additives in each sample fluid are indicated in the table below
with by weight" indicating the amount of ihe particular component by weight of Additive .1 +
Additive 2. The abbreviation ¾ai/sk" in the table below indicates gallons o f the particular
component per 94-pound sack of Additive 1 and Additive 2
[0073] The CKD used was supplied by o lci (US) nc ., f o Ada, Oklahoma. The
shale used was supplied by Texas Industries, Inc.. from Midlothian, Texas. The pumice used was
either S-200 or DS-300 lightweight aggregate available fro Hess Pumice Products, Inc. The
silica flour used was SSA-i™ cement additive, from Halliburton Energy Services, Inc. The
course silica flour used was SSA-2™ course silica flour, from Halliburton Energy Services, inc.
The metakaolin used was etaMa rneiakaoiiu, from BASF. Th amorphous silica used was
SILICALITE™ cement additive, from Halliburton Energy Services, Inc. The per it used was
supplied by Hess Pumice Products, inc. The s ag used was supplied by LaFarge North America.
The Portland cement te ground with pumice was te e cement, Halliburton Energy
Services. nc . The fly ash used was POZ IX* cement additive, from Halliburton Energy
Services, nc . The micro-fine cement used was MICRO MATRIX* having an average particle
size of 7.5 microns, from Halliburton Energy Services, inc. The rice husk ash used was supplied
by Rice Hull Specialty Products, Stuttgart, Arkansas. The biopolymer used was supplied by CP
elco. Sa Diego, California. The bante used was supplied by Baroid Industrial Drilling
Products. The latex used was Latex 3000™ cement additive from Halliburton Energy Services,
Inc. The gro u d rubber used was UFECEM™ . 0 from Halliburton Energy Services, c. The
nan -c ay e was supplied by an or nc . The set retarder used was SCR- 100™ cement
retarder, from Halliburton Energy Services, Inc. SCR- 00™ cement retarder is a . copolymer of
acrylic acid and 2-ac.ry!am.ido-2-methylpropane sulfonic acid.
[0074 After preparation, the sample fluids were allowed to cure for seven days in a 2"
by 4" metal cylmder that was placed in a water bath at i 0 F to form set cylinders. Immediately
after removal fro the water bath, destructive compressive strengths were determined using a
mechanical press in .accordance with API RP 10B-2 The results of this test are set fort below,
a o-
32 6.15 < j 100 2 0 102.5
j j 1 L-ktV 1 1
[00 5 Accordingly, he above example illustrates that a consolidating spacer fluid
comprising CKD may be capable of consolidation. For example, 7-day compressive strengths of
00 psi or even higher were observed for certain sample slurries.
EXAMPLE 7
[0076] The following series of"tests were- performed to evaluate the thickening times of
consolidating spacer fluids, or this example, the thickening times for Sample Fluids 1-32 fro
Example 6 were determined. As indicated below, the compositions for Samples Fluids 1.1-32
were the same as from Example 6 except the concentration of the cement set retarder was
adjusted for certain samples. The thickening time, which is the time required for the
compositions to reach 70 Bearden units of consistency, was determined for each fluid at 2 3 { ' in
accordance with API RP -2. The results of this test are se forth belo w.
[0077] Accordingly, the above example illustrates that a sellable spacer fluid may have
acceptable thickening tiroes for certain applications.
EXAMPLE 8
[0078] The following series of tests were performed to evaioate the rheoJogiea! properties
of consolidating spacer fluids. For this example, the theological properties of Sample Fluids 11-
32 were determined. The theological values were determined using a Farm del 35 Viscometer.
Dial readings were recorded at speeds of 3. 6 , 30, 60, 0, 200, 300, and 600 with a Bl bob, an
rotor, and a i.O spring. An additional sample was use lor this specific test. It is Sample Fluid
33 and comprised bariie and 0.5% of a suspending agent by weight of the bariie. The suspending
agent was SA, - . . , available from Halliburton Energy Services, Inc. The water was included
in an amount sufficient to provide a density of .5 ppg. Sample 33 rheoiogical properties were
measured twice at two different temperatures and the values per temperature were averaged to
present the data shown below. Temperature is measured in degrees Fahrenheit The results of this
test are set forth below.
TABLE S

[0079] Accordingly, the above example indicates thai a consolidating spacer fluid may
have acceptable theological properties for a particular application.
EXAMPLE 9
[0080] The following series of tests were performed to further evaluate the compressive
strength of consolidating spacer fluids. Ten samples, labeled Sample Fluids 34-43 i the table
be ow were prepared, havsng a density of . ppg using various concentrations of additives. The
amount of these additives in each sample are indicated in the tabic below with. " by weight"
indicating the amount of the particular component by weight of the dry solids, which is the CKD,
the Portland cement, the cement accelerator, the fly ash, and/or the lime. The abbreviation
ga in the table be ow indicates gallons o the particular component per 94-pound sack of the
dry solids.
[DOS The CKD used was Mountain C D from Laramie Wyoming, except for Sample
Fluid 43 which used CKD from oici (US) inc., Ada, Oklahoma. The Portland cement use i
Sample Fluids 34 and 35 was CEMEX 1 ype Portland cement, from CEMEX USA. The cement
accelerator used in Sample Fluid 34 was CAL-SEAL™ accelerator, from Halliburton Energ
Services c. CAL-SEAL™ Accelerator is gypsum. The Class F fly ash used in Slurries 37-41
was from Coal Creek Station. The Class fly ash used in Slurries 36 was from LaFarge North
America.
[0082] After preparation, the samples were allowed to cure for twenty-four or forty-eight
hours in a by 4" metal cylinder tha was placed in a water bath at 0"F to form set cylinders.
For certain samples, separate cylinders were cured for twenty-four hours and .forty-eight hours.
Immediately after removal from the water bath, destructive compressive strengths were
determined using a mechanical press in accordance with API RP 108-2. The results of this test
are set forth below.
[0083] Accordingly, th above example illustrates that a consolida i
av acceptable compressive strengths for certain applications.
EXAMPLE 1
[0084] The following series of tests were performed to evaluate the static gel strength
development of consolidating spacer fluids. Two samples, labeled Sample Fluids 44 and 45 were
prepared having a density of 1 and 13,5 ppg respectively using various concentrations of
additives. The component concentrations of each sample are as follows:
[0085] For Sample Fluid 44, the sample comprised a blend of CKD (80% by weight), fly
ash ( 6 by weight) and hydrated lime (4% by weight). The sample also comprised a
suspending aid in an .amount of 0,4% by weight of the blend. Sufficient water was included in
the sample to provide a density of ppg. The CKD used was from Holcim (US) Inc., Ada,
Oklahoma, The f y ash used was ROZM C* cement additive, from Halliburton Energy Services,
ac . The suspending agent was SA , available from Halliburton Energy Services, nc.
[0086] For Sample Fluid 45, the sample comprised a mixture of CKD (80% by weight),
fly ash ( % by weight), and hydrate lime 4% by weight). Sufi cient water was included in the
sample to provide a density of 13.5 ppg. The C used was from Holcim ( S) .Inc., Ada,
Oklahoma. The f y ash used was P0 2 LX cement additive, from Halliburton Energy Services,
nc.
[0087] The static gel strength o the samples was measured in accordance with API
Recommended Practice on Determining the Static Gel Strength of Cement Formations,
ANSI/API Recommended Practice i0B-6. FIGS. 1 and 2 show the static gel strength
measurements for Sample Fluids 44 and 45, respectively, as a func tion of time.. As seen in the
figures, the samples progress through the transition time, defined as the time between 0 SGS
and 500 SGS, very quickly with a total transition time of 1 minutes for the sample 34 and 6
minutes for sample 35. These short transition times are faster than most cement compositions.
EXAMPLE 11
[0088] The following tests were performed to evaluate the static gel strength
development of consolidating spacer fluids. Two samples, labeled Samples Fluids 46 and 47 wer
prepared having a density of 3.002 and . .999 ppg respectively using various concentrations of
additi ves. The component concentrat ions of each sample are as follows:
[0089] For Sample Fluid 46 the sample comprised blend of CKD ( 0 by weight),
POZ X* (50% by weight of the CKD , HR*- 0 (!% by weight of the CKD), -25 (PS)
(0.6% by weight of the CKD). and D-A 5000 (0.5% by weight of the CKD) Sufficient water
was included in the sample to provide a density of 13.002 ppg. The CKD used was fro olc i
(US) Inc. Ada, Oklahoma. POZMiX* ' cement additive s from Halliburton Energy Services, nc .
i:iR¾-6 is a cement retarder available .from Halliburton Energy Services, nc . R'*'-25 is a
cement retarder available from Halliburton Energy Services, Inc. i Air' 5000 is a defoamer
available from Halliburton Energy Services, nc.
[0090] For Sample Fluid 4 , the sample comprised a blend of CKD ( 0% by weight),
SA- 5 (0.4% by weight of th CKD), a d D-Air 5000 (0.5% by weight of the CKD). Sufficient
water was included i the sample to provide a density of 999 ppg. The CKD used was from
Holcim (US) inc., Ada, Oklahoma. is a suspending agen available from Halliburton
Energy Services, h e. D-Air' *' 5000 is a defoamer available from Halliburton Energy Services,
nc.
[0091] The static ge strength of the samples was measured in accordance with API
Recommended Practice on Determining the Static Gel Strength of Cement Formations,
ANS ARϊ Recommended Practice 10B-6. Table 8 shows the static eel strength measurements
for samples 36 and 37, respectively.
TABLE
As seen in the table. Sample fluid 47 progresses through the transition time, defined as the time
between 0 SOS an 500 S S, very quickly with a total transition time of 1 minutes. Sample
Fluid 46 is ranch slower taking over an ho r to progress through the transition time. The short
transition time of Sample Fluid 47 is faster than most ceme t compositions
[0092] t should be understood that the compositions and methods are described in terms
of "comprising," "containing," or "including" various components or steps, the compositions and
methods can also "consist essentially of or "consist of the various components and steps.
Moreover, the indefinite articles "a" or an " as used in the claims, rc defined herein to mean
one or more than one of the element that it introduces
[0093] For the sake of brevity, only certain ranges are explicitly disclosed herein.
However, ranges from any Iower limit may be combined w th any upper limit to recite a range
not explicitly recited, as wel as, ranges from any lower limit ay be combined with any other
lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit
may be combined with any other upper limit to recite a range not explicitly recited. Additionally,
whenever a numerical range with a lower limit and an upper limit is disclosed, any number and
any included range falling within the range are specifically disclosed. n particular, every range
of values (of the form, "from about a to about b, or, equivalenily, "from approximately a to
or, equivalently, "from approximately a b") disclosed herein is to be understood to set forth every
number and range encompassed within the broader range of values even if not explicitly recited.
Thus, every point or individual value may serve as its own lower or upper limit combined w th
any other point or individual value or any other lower or upper limit, to recite a range not
explicitly recited.
[0094] Therefore, the present invention is well adapted to attain the ends d advantages
mentioned as well as those that are inherent therein. The particular embodiments disclosed above
are illustrative only, a th present invention may be modified and practiced in different but
equivalent manners apparent to those skilled in the art having the benefit of the teachings herein.
Although individual embodiments are discussed, the invention covers all combinations of all
those embodiments. Furthermore n limitations ar intended to the details of construction or
design herein shown, other than as described i the claims below. Also, the terms in the claims
hav their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee.
It is therefore evident that the particular illustrative embodiments disclosed above may be altered
or modified and all such variations are considered within the scope and spirit of the present
invention. If there is any conflict in the usages of a word or term in this specification and one or
more patent(s) or other documents that may be incorporated herein by reference, the definitions
tha are consistent with this specification should be adopted.

we claims:-
1 A method of displacing a drilling fl ui disposed in a well bore annulus,
comprising;
designing a spacer tluid to meet at least one property under predetermined we l
bore conditions, wherein the property is selected from the group consisting of: ( ) a yield point of
from about 25 Pascals to about 250 Pascals, (i a static gel strength of from about 70 bf/
to about 500 bf/ 0 t , (iii) a yield limit i n compression fro about psi to about 2,000 psi, and
(iv) an unconfi ned uniaxial compressive strength of from about 5 psi to about ,000 psi;
using the spacer fluid t displace at least a portion of th drilling fluid fro the
well bore annulus; and
allowing at least a portion of the spacer fluid to consolidate in the well bore, and
wherein the portion of the spacer fluid consolidates in the well bore to meet the property
2 The method of claim 1 wherein the drilling fluid comprises an oil-based drilling
fl uid
3. The method of claim 1 wherein the spacer fluid comprises cement kiln dust
4 The method of claim 1wherein the spacer fluid comprises lime ki l dust ,
5. The method of claim 1 wherein the spacer fluid comprises kiln dust in an amount
in a range of from about 1% to about 60% by weight of the spacer fluid.
6. The method of claim 1 further comprising introducing a cement composition into
the well bore annulus after the spacer fluid, wherein the spacer fluid separates the cement
composition from the drilling fluid.
7. The method of claim further comprising running a bond log on the portion of
the spacer fluid in the well bore a ulus to measure bonding of the consolidating spacer fluid to a
pipe string in the well bore,
8 The method of claim 1 wherein the spacer fluid is foamed and has a density in a
range of f om about pounds per gallon to about 13 pounds per gallon.
9. The method of claim 1 wherein the consolidating spacer fluid comprises at least
one additive selected from the group consisting of a tree water control additive, a lightweight
additive, a foaming agent, a supplementary cementitious material, a weighting agent of any
suitable size, a visc s ly ing agent, a fluid loss control agent, a lost circulation material, a filtration
control additive, a dispersani a defoanier, a corrosion inhibitor, a scale inhibitor, a formation
conditioning agent, a water-wetting surfactant, and any combination thereof,
0 . The method of claim 1 wherein the spacer fluid comprises at least one additive
selected from the grou consisting of kiln dust, gypsum, fly ash, bentonite, hydr yethyl
cellulose, sodium silicate, a hollow microsphere, gilsonile, peril e, a gas, an organic polymer, a
biopolymer, latex, ground rubber, a surfactant, crystalline silica, amorphous silica, silica flour,
fumed silica, nano-clay, salt, fiber, hydratabie clay, rice husk ash, micro-line cement, meta ao n,
zeolite, shale, pumicite, Portland cement, Portland cement interground with pumice, bartte, slag,
lime, and any combination thereof,
The method of claim wherein the spacer fluid comprises at least one
cementiiious material selected from the group consisting of Portland cement, Portland cement
interground with pumice, micro-fine cement, slag, f y ash, rice husk ash, pumicite, gypsum, and
any combination thereof.
12 , The method of claim 1 wherein the port ion of the spacer fluid consolidates in the
well bore to have a static gel strength of from about 70 f Oft 2 to about 5 0 ? 0 and/or
a yield point of from about 25 Pascal to about 250 Pascals
. The method of claim 1 wherein the portion of the spacer fluid consolidates in the
well bore to have a yield limit in compression from about psi t about 2,000 psi
14. The method of claim ! wherein the portion of the space fluid consolidates in the
we l bore to have an ncon e uniaxial compressive strength of from about 5 psi to about
.000 psi.
. The method of claim 1 wherein the portion of the spacer fluid has a zero gel time
of about 8 hours or less.
. The method of claim wherein the portion of the spacer fluid consolidates to
develop a static gel strength of about 500 l t? 00 ft or more in a time from about minutes to
about hours,
17. The method of claim .1 wherein the portion of the spacer fluid consolidates has a
transition time o about 45 minutes or less,
18 The method of claim wherein the predetermined well bore conditions comprise
temperature and pressure.
19. A method of displacing a drilling fluid disposed in a well bore annulus,
comprising:
using a consolidating spacer fluid to displace at least a portion of the drilling flui
from the we l bore annulus; and
allowing at least a portion of the consolidating spacer fluid to consolidate in the
well bore annulus, wherein the portion of the consolidating spacer fluid has a zero gel time of
about 4 hours o less.
26. The method of claim .9 wherein the consolidating spacer fluid comprises cement
kiln dust
21. The method of claim . wherein the consolidating spacer fluid comprises at least
one additive selected from the group consisting of kiln dust, gypsum, fly ash, ben onite
hydroxyethyl cellulose, sodium silicate, a ho ow microsphere, g iso ite perlite, a gas, a organic
polymer, a biopoiyn r latex, ground rubber, a surfactant, crystalline silica, amorphous silica,
silica flour, fumed silica, nano-clay, sa t, fiber, hydratabte clay, rice husk ash, micro-fine cement,
metakaoHn, zeolite, shale, puniicife, Portland cement, Portland cement i e rground with pumice,
bariie, s ag, l e, and any combination thereof.
22. The method of claim 9 further comprising introducing a cement composition
into the well bore an ul us, wherein the consolidating spacer fluid separates the cement
composition from the drilling fl uid
23. The method of claim 22 wherein the portion of ihe consolidating spacer fluid
consolidates in the well bore to hav a transition time that s shorter tha a transition time of the
cement composition.
24 The method of claim 1 wherein the portion of the consolidating spacer fl uid has
a transition time of about 45 minutes or less.
25. The method of claim 9 wherein the portion of the consolidating spacer fluid has
a transition time of about 20 minutes or less.
26. Th method of claim 19 wherein the portion of the consolidating spacer fluid
consolidates in th well bore to have a yield limit in compression from about psi to abou 2,000
psi.
27. The method of claim 19 wherein the portion of the consolidating spacer fluid
consolidates in the well bore to hav an unconrlned uniaxial compressive strength of front about 5
ps to about ,000 psi.
28. The method of claim 19 wherein the portion of the consolidating spacer fluid
consolidates t o develop a static gel strength of about 500 bf Of or more in a time from about
minutes to about hours.
29. The method of claim wherein the consolidating spacer fluid is foamed and has
a density in a range of .from about 4 pounds per gallon to about pounds per gallon.
30. A method of displacing a drilling fluid disposed n a we l bore annulus,
comprising:
using a consolidating spacer fluid to displace at least a portion of the dri lling fluid
from the well bore annulus: and
allowing at least a portion o f the consolidating spacer fluid to consolidate in the
well bore annulus, wherein the portion of the consolidating spacer fluid has a transition time of
about 45 minutes or less.
3 i . The method of claim 30 wherein the consolidating spacer fluid comprises cement
kiln dust,
32. The method of claim 30 wherein the consolidating spacer fluid comprises at least
one additive selected from the group consisting of kiln dust, gypsum, fly ash, bentonste,
hydroxyethyl cellulose, sodium silicate, a hollow microsphere, g sonit , perlite. a gas, an organic
polymer, a biopolymer, latex, ground rubber, a surfactant, crystalline silica, amorphous silica,
silica flour, fumed silica, nano-clay, salt, fiber, hydratable clay, rice husk ash, micro-fine cement,
metakao n, zeolite, shale, puniieite, Portland cement, Portland cement in ergro nd with pumice,
barite, stag, lime, and any combination thereof,
33. The method of claim 30 further comprising introducing a cement composition
into the wel bore ann s wherein the consolidating spacer fluid separates the cement
composition from the drilling fluid,
34. The method of claim 3 wherein the transition time o the por tion of the
consolidating spacer fluid is shorter than a transition time of the cement composition,
35 The method of claim 30 wherein the transition time of the portion o f the
consolidating spacer fluid is about 20 minutes or less.
36. The method of claim 30 wherein the portion of the consolidating spacer fluid
consolidates in th well bore to have a yield limit in compression from about psi to about 2,000
psi.
37. The method of claim 30 wherein the portion of the consolidating spacer fluid
consolidates in the well bore to hav an unconflned uniaxial compressive strength of from about 5
psi to about ,000 psi,
38. The method of claim 30 wherein the portion of the consolidating spacer fluid
consolidates to develop a static gel strength of about 500 !b f/ ft or more in a time from about
minutes to about. 4 hours.
39 The method of claim 30 wherein the consol idating spacer fluid is foamed and has
a density in a range of .from about 4 pounds per gallon to about pounds per gallon.
40. A method of displacing a drilling fluid disposed in a we l bore annulus,
comprising:
introducing a consolidating spacer fluid into the well bore an u s to displace at
least a portion of the drill ing fluid from the well bore annulus; and
allowing at least a portion of the consolidating spacer fluid to consoiidate in the
well bore annul us;
wherein the consolidating spacer fl id comprises water a d at least o e additive
selected fro the group consisting of kiln dust, gypsum, fly ash, bentonite, hydroxyethyl
cellulose, sod um silicate, a hollow microsphere., giiso te perl he, a gas an organic polymer, a
biopolynier, latex, ground rubber, a surfactant, crystalline silica, amorphous silica, silica flour,
fumed silica, nano-clay, sa t, fiber, hydratable clay, rice husk ash, micro-fine cement, metakaofin,
zeolite, shale, pumicite, Portland cement, Portland cement i erground with pumice, barite, slag,
lime, and any co binatio thereof; and
wherein the portion of the consolidati ng spacer fluid has a zero gel time of about
4 hours or less.
. The method of claim 40 wherem the drilling fluid comprises an oil-based drillmg
fluid.
42. The method of claim 40 wherein the consolidating spacer fluid comprises the kiln
dust and the kil dust comprises cement kil dust.
43. The method of claim 40 wherein the consolidating spacer fl uid comprises the kiln
dust and the kiln dust comprises lime kiln dust,
44. The method of claim 40 wherein the consolidating spacer fl uid comprises the kiln
dust and the kiln dust is present in the consolidating spacer fluid in an amount i a range of from
about 1% to about 60% by weight of the consolidating spacer fluid.
45. The method of claim 40 wherein the consolidating spacer fluid comprises the fly
ash, the slag, the pumicite, the lime, and/or the bar e.
46. The method of claim 4 further comprising introducing cement composition
into the well bore annulus after the consolidating spacer fluid, wherein the consolidating spacer
fluid separates the cement composition from the drilling f id.
47. The method of claim 40 wherein the spacer fluid is foamed and has a density n a
range of front about 4 pounds per gallon to about 1 pounds per gallon.
48. The method of claim 40 wherein the portion of the consolidating spacer fluid has
transition time of about 45 minutes or less.
49. I he method of claim 40 wherein the portion of the consolidating spacer fluid has
a transition time of about 20 minutes or less.
50. A method of displacing a drilling fluid disposed in well bore annulus,
comprising:
introducing a consolidating spacer fluid into the we l bore annulus to displace at
least portion of the drilling fluid from the well bore annulus;
allowing at least a portio of the consolidating spacer f id to consolidate in the
we l bore annulus; and
measuring consolidation properties of the portion of the consolidating spacer fluid
in the well bore annulus.
. The method of claim 50 wherein the consolidating spacer fluid comprises cement
kiln dust
52. The method of claim 50 wherein the consolidating spacer fluid compri ses im
kiln d t ..
53. The method of claim 50 wherein the consolidating spacer fluid comprises kiln
dust, and wherein the kiln dust is present in the consolidating spacer fluid in an a ou t in a range
of fro about 1% to about 60% by weight of the consolidating spacer fluid
4. The method of clai 50 further comprising introducing a . cement composition
into the well bore annulus after the consolidating spacer fluid, wherein the consolidating spacer
fluid separates the cement composition from the oil-based drilling fl u id .
55. The method o f claim 50 wherein the consolidating spacer fluid is foamed and has
a density in a range of from about 4 pounds per gallon to about pounds per gal lon.
56. The method of claim 50 wherein the portion of the consolidating spacer fluid
forms a bond between a subterranean formation and a pipe string disposed in th well bore or
between the pipe string an a larger conduit disposed in the well bore, and wherein the bond Song
measures the bond formed by the consolidating spacer .fluid.
57. The method of claim 50 wherein the step of measuring consolidation properties
comprises running a bond og
58. A method of evaluating a spacer fluid for use in separating a drill ing fluid and a
cement composition in a well bore comprising:
providing the spacer f d; and
measuring a transition time of the spacer fluid.
59 The method of claim 5 wherein th transition time of the spacer fl ui is about 45
minutes or less a well bore conditions.
60. The method of claim 58 wherein the transition time of the spacer fluid s about 20
minutes or less at a temperature in a range of from about 40°F to about 300 and a pressure in a
range of from about 2,000 psi to about ,000 pst.
6 1. The method of claim 58 further comprising measuring a compressive strength of
th .spacer fluid.
62. The method of claim 58 further comprising: providing cement composition,
measuring a transition time of the cement composition, and comparing the transition time of the
cement composition a d the transition time of the spacer fluid.
63. Th method of claim 62 wherein the transition time of the spacer f id is shorter
than the transition time of th cement composition.
64. A method of evaluating a spacer fluid for use in separating a drilling fluid and a
cement composition in a well bore comprising:
providing the spacer fluid; and
measuring a zero gel time of the spacer fluid.
65. The method of claim 64 wherein the zero gel time of the spacer fluid is about 4
hours or less at well bore conditions.
66. The method of claim 64 further comprising measuring compressive strength of
the spacer fluid.
67. The method of claim 64 ftuther comprising: providing a cement composition,
measuring a zero gel time of the cement composition, and comparing the zero gel time of the
cement composition and the zero gel time of the spacer fluid.
68. The method of claim 67 wherein the ¾ero gel time of the spacer fluid is longer
than the zero time of the cement composition.
69. A consolidating spacer fluid that separates a drilling fluid and a cement
composition in a well bore, comprising:
water; and
at least one additive selected from the gr p consisting of kiln dust, gypsum, fly
ash, bentonite, hydroxyethyl cellulose sodium silicate, a hollow microsphere, gilsonite, perlite, a
gas, an organic polymer, a biopoSytrter, latex, ground rubber, a surfactant, crystalline silica,
amorphous silica, silica flour, fumed silica, nano-elay, salt, fiber, hydratable clay, rice husk ash,
micro-fine cement, metakaoiin, zeolite, shale, pumicite, Portland cement, Portland cement
interground with pumice, barite, slag, ime, and any combination thereof; and
wherein the portion of the consolidating spacer fluid has a zero gel time of about
4 hours or less,
70. The consolidating spacer fluid of claim 69 wherein the consolidating spacer fluid
comprises the kiln dust, the k dust comprising cement kiln dust.
7 1 The consolidating spacer fluid of claim 69 wherein the consolidating spacer fluid
r the k dust, the kiln dust comprising lime kiln dusi,
72 Th consolidating spacer fluid of claim 69 wherein th consolidating spacer fluid
comprises the kil dust i an amount in a range of from about % to about 60% b weight of the
consolidating spacer fl uid
73 Th consolidating spacer fluid of claim 69 wherein th consolidating spacer fluid
is foamed and has a density in a range of from about 4 pounds per gallon to about 3 pounds per
gallon.