MOBILE SYSTEMS AND METHODS OF
SUFFICIENTLY TREATING WATER SO THAT
THE TREATED WATER MAY BE UTILIZED IN WELL-TREATMENT
OPERATIONS
TECHNICAL FIELD
[001] The present invention generally relates to mobile systems and methods for the
treatment of water so that it may be used in well-treatment operations.
SUMMARY OF THE INVENTION
[002] According to one aspect of the invention, a mobile water treatment system for
sufficiently treating water so that the treated water may be utilized in well-treatment
operations is provided. The system comprises:
(a) a mobile platform;
(b) an input pump, wherein the input pump is mounted on the mobile platform
and operatively connected to be capable of pumping a treatment stream through the
system;
(c) a centrifugal separator, wherein the centrifugal separator is mounted on
the mobile platform and operatively connected downstream of the input pump to
centrifugally treat the treatment stream;
(d) a borate filter, wherein the borate filter is mounted on the mobile platform
and operatively connected downstream of the centrifugal separator to filter the treatment
stream, and wherein the borate filter is capable of removing at least some of a borate that
may be present in the treatment stream when the treatment stream is at a pH of 8 or
above; and
(e) a chemical-additive subsystem, wherein the subsystem is mounted on the
mobile platform, and wherein the subsystem is operatively connected to be capable of:
(i) selectively adding one or more chemical agents to the treatment
stream upstream of the centrifugal separator, wherein the chemical agents can be selected
to be capable of precipitating dissolved ions selected from the group consisting of:

sulfate, calcium, strontium, or barium, magnesium, iron, and any combination thereof in
any proportion that may be present in the treatment stream; and
(ii) selectively adding a chemical agent to the treatment stream
upstream of the borate filter to increase the pH of the treatment stream to 8 or above,
wherein the pH increasing agent can be the same or different from one of the chemical
agents that can be selected to be capable of precipitating dissolved sulfate, calcium,
strontium, or barium, magnesium, or iron ions.
[003] According to another aspect of the invention, a method of water treatment for
sufficiently treating water so that the treated water may be utilized in well-treatment
operations is provided. According to this aspect, the method comprises the steps of:
bringing a mobile water treatment system according to the invention to a source of water;
and using the mobile water treatment system to treat water to obtain treated water.
[004] According to yet another aspect of the invention, a method of water treatment
for sufficiently treating water so that the treated water may be utilized in well-treatment
operations, wherein the method comprises the steps of:
(a) pumping water as part of a treatment stream;
(b) centrifugally removing at least some of the particulate that may be present
in the treatment stream; and
(c) filtering out at least some of the borate that may be present in the treatment
stream with a filter media capable of removing a borate from the treatment stream at a pH
of 8 or above, wherein at least during the step of filtering of borate, the pH of the
treatment stream is or is adjusted to be 8 or above;
(d) chemically treating the treatment stream, wherein the step of chemically
treating comprises at least one of the following steps:
(i) adding a water-soluble calcium, strontium, or barium halide to the
treatment stream upstream of the centrifugally removing step, wherein the calcium,
strontium, or barium halide is capable of precipitating at least some of the sulfate ions
dissolved in the treatment stream as calcium, strontium, or barium sulfate;
(ii) adding a water-soluble carbonate to the treatment stream upstream
of the centrifugally removing step, wherein the carbonate is capable of precipitating at
least some of the calcium ions dissolved in the treatment stream as calcium carbonate;

(iii) adding a water-soluble alkali metal hydroxide to the treatment
stream upstream of the centrifugally removing step, wherein the hydroxide is capable of
precipitating at least some of the magnesium and iron ions dissolved in the treatment
stream as magnesium and iron hydroxide; and
(iv) adding a pH increasing agent to the treatment stream upstream of
the borate filtering step, wherein the pH increasing agent is capable of increasing the pH
of the treatment stream to at least 8, and wherein the pH increasing agent can be the same
or different from one of the chemical agents selected to be capable of precipitating
dissolved calcium, strontium, or barium, magnesium, or iron ions.
[005] According to another aspect of the invention, a method of water treatment for
sufficiently treating water so that the treated water may be utilized in well-treatment
operations is provided, wherein the method comprises the steps of:
(a) pumping water as part of a treatment stream;
(b) centrifugally removing at least some of the particulate that may be present
in the treatment stream;
(c) filtering out at least some of the borate that may be present in the treatment
stream with a filter media capable of removing a borate from the treatment stream at a pH
of 8 or above, wherein at least during the step of filtering of borate, the pH of the
treatment stream is or is adjusted to be 8 or above;
(d) adding a water-soluble calcium, strontium, or barium halide to the
treatment stream upstream of the centrifugally removing step, wherein the calcium,
strontium, or barium halide is capable of precipitating at least some of the sulfate ions
dissolved in the treatment stream as calcium, strontium, or barium sulfate; and
(e) adding a pH increasing agent to the treatment stream upstream of the
borate filtering step, wherein the pH increasing agent is capable of increasing the pH of
the treatment stream to at least 8.
[006] This method preferably further includes the step of: adding a water-soluble
alkali metal hydroxide to the treatment stream upstream of the centrifugally removing
step, wherein the hydroxide is capable of precipitating at least some of the magnesium
and iron ions dissolved in the treatment stream as magnesium and iron hydroxide.

[007] According to another aspect of the invention, a method of water treatment for
sufficiently treating water so that the treated water may be utilized in well-treatment
operations is provided, wherein the method comprises the steps of:
(a) pumping water as part of a treatment stream;
(b) centrifugally removing at least some of the particulate that may be present
in the treatment stream;
(c) filtering out at least some of the borate that may be present in the treatment
stream with a filter media capable of removing a borate from the treatment stream at a pH
of 8 or above, wherein at least during the step of filtering of borate, the pH of the
treatment stream is or is adjusted to be 8 or above;
(d) adding a water-soluble carbonate to the treatment stream upstream of the
centrifugally removing step, wherein the carbonate is capable of precipitating at least
some of the calcium ions dissolved in the treatment stream as calcium carbonate; and
(e) adding a pH increasing agent to the treatment stream upstream of the
borate filtering step, wherein the pH increasing agent is capable of increasing the pH of
the treatment stream to at least 8, and wherein the pH increasing agent can be the same or
different from the carbonate selected to be capable of precipitating dissolved calcium
ions.
[008] This method preferably further includes the step of: adding a water-soluble
alkali metal hydroxide to the treatment stream upstream of the centrifugally removing
step, wherein the hydroxide is capable of precipitating at least some of the magnesium
and iron ions dissolved in the treatment stream as magnesium and iron hydroxide, and
wherein the pH increasing agent can be the same or different from the hydroxide selected
to be capable of precipitating dissolved magnesium and iron ions.
[009] According to the systems and methods of the invention, water can be treated
to obtain treated water having a substantially reduced concentration of dissolved sulfate
or calcium ions, preferably a substantially reduced concentration of magnesium and iron
ions, and a substantially reduced concentration of dissolved borate ions. These and
further aspects of the invention are described in more detail below.

Brief Description of the Drawings
[0010] A more complete understanding of the present disclosure and advantages
thereof may be acquired by referring to the following description taken in conjunction
with the accompanying drawings, which:
[0011] Figure 1 is a flow diagram representing a presently preferred embodiment of a
water treatment system for sufficiently treating water so that the treated water may be
utilized in well-treatment operations.
[0012] Figure 2 is a representative example of the structure of a hydrocyclone,
shown in cross-section.
[0013] Figure 3 is a representative example of the structure of a centrifuge, shown in
cross-section.
[0014] Figure 4 is an illustration of a mobile water treatment system according to the
invention, including a mobile water treatment system of the type represented in Figure 1
mounted on a mobile platform (a trailer), and further including a reservoir of produced
fluid (at least one tanker trailer) and a reservoir of treated fluid (at least one tank).
[001 S\ Figure 5 is an illustration of another mobile water treatment system according
to the invention, including a mobile water treatment system of the type represented in
Figure 1 mounted on a mobile platform (a trailer), and further including a reservoir of
produced fluid (a holding pit) and a reservoir of treated fluid (a holding pit).
DETAILED DESCRIPTION
[0016] Large quantities of water are required in well-treatment operations for
producing oil and gas from subterranean formations. For example, a single well
fracturing operation may require several millions of gallons of treatment water be injected
into the well.
[0017] In the production of oil and gas, great quantities of water are produced.
Sources of produced water can include water that may have been injected into the
subterranean formation as part of a well-completion or well-treatment process, water that
may have been injected as part of an injection-well driving process, connate water, and
any mixture of any of these. For example, for every barrel of oil produced from a well, it
is typical to also obtain about 10 barrels of produced water. Large quantities of produced

water continue to be disposed of as waste water, for example, by reinjecting the produced
water into a well.
[0018] With the rising demand for freshwater, increasing public concern for the
environment, and with the rising costs of obtaining freshwater, it would be desirable to be
able to use produced water in common well-treatment operations.
[0019] Produced water is brackish or saline water that may contain hydrocarbon and
other materials. According to this invention, it is recognized that, in general, for water to
be suitable for use in common well-treatment operations, however, does not require that it
be seawater, freshwater, or potable water. Usually all that is required is water that does
not contain materials that would be particularly detrimental to the chemistry involved in
such well-treatment operations.
[0020] Of particular concern for use in common well-treatment operation is the
avoidance of water containing undesirably-high concentrations of inorganic ions having a
valence state of two or more. As is well known in the oil and gas industry, such ions can
interfere with the chemistry of forming or breaking certain types of viscous fluids that are
commonly in various well-treatment operations.
[0021] Cations that are of common concern include dissolved alkaline earth metal
ions, particularly calcium and magnesium ions, and may also include dissolved iron ions.
[0022] An anion of common concern includes sulfate.
[0023] Normally, however, a high concentration of both calcium ions and sulfate
anions in a water source is unlikely. Calcium ions tend to react with sulfate ions to
produce calcium sulfate, which is an insoluble salt that tends to precipitate from solution.
Similarly for strontium ions and sulfate ions or barium ions and sulfate ions. Thus, a
problem with using water for common well-treatment operations tends to be either an
undesirably-high concentration of calcium, strontium, or barium ions or an undesirably-
high concentration of sulfate ions.
[0024] Borates have the chemical formula B(OR)3, where B = boron, O = oxygen,
and R'= hydrogen or any organic group. At higher pH ranges, e.g., 8 or above, a borate is
capable of increasing the viscosity of an aqueous solution of a water-soluble polymeric
material such as a galactomannan or a polyvinyl alcohol. Afterwards, if the pH is
lowered, e.g., below 8, the observed effect on increasing the viscosity of the solution can
be reversed to reduce or "break" the viscosity back toward its original lower viscosity. It

is also well known that at lower pH ranges, e.g., below 8, borate does not increase the
viscosity of such a water-soluble polymeric material. This effect of borate and response
to pH provides a commonly-used technique for controlling the cross-linking of certain
polymeric viscosity-increasing agents. The control of increasing the viscosity of such
fluids and the subsequent "breaking" of the viscosity tends to be sensitive to several
factors, including the particular borate concentration in the solution.
[0025] Without being limited by any particular theoretical explanation, a borate is
believed to be capable of forming labile bonds with two alcohol sites of other molecules.
This ability of a borate to react with the alcohol sites can be employed to "cross-link"
alcohol sites on different polymer molecules (or possibly other parts of the same
molecule) that find their way in a solution to become adjacent to one another. The pH of
an aqueous fluid controls the equilibrium between boric acid and borate anion in solution.
At higher pH ranges, the equilibrium shifts toward a higher concentration of borate ion in
the water.
[0026] For example, by increasing the pH of a fluid to 8 or above, although usually in
the range of about 8.5 -12, a borate-releasing compound such as boric acid releases
borate ions, which become available for cross-linking a water-soluble polymer having
alcohol sites. By subsequently lowering the pH of the fluid to a pH of below 8, for
example, by adding or releasing an acid into the fluid, the equilibrium shifts such that less
of the borate anion species is in solution, and the cross-linking can be broken, thereby
returning such a gelled fluid to a much lower viscosity.
[0027] Regardless of the theoretical chemical mechanism of borate cross-linking,
which may not yet have been perfectly elucidated and understood, borates are widely
used in the oil and gas industry to selectively control an increase and subsequent break in
the viscosity of an aqueous well-treatment fluid containing a water-soluble polymeric
material having alcohol sites. A fluid having a viscosity greater than that of water can be
useful in various well-treatment operations, such as in a fracturing a well where the
increased viscosity is used to help carry a proppant through a wellbore to a desired
location. After having served the intended purpose of a fluid having an increased
viscosity, the viscosity of the fluid can be broken to help return the fluid back to the
surface as some of the produced water. Therefore, borates are commonly found in
produced water.

[0028] Borate cross-linking may be undesirable in some well-treatment operations,
however, which may interfere with the desired chemistry for a particular well-treatment
operation. Thus, the presence of borates or the presence of unknown concentrations of
borates is often undesired.
[0029] Borates also may be naturally occurring in freshwater, seawater, and connate
water, any of which may be found in treated wells, but usually in such low concentrations
that the borates would not normally be expected to interfere with the chemistry of
common well-treatment fluids. As borates are commonly used in various well-treatment
fluids, however, undesirably high concentrations of borates are likely to be present in
produced water.
[0030] According to the invention, it is recognized that treating produced water or
other source of water to reduce any substantial concentrations of one or more of the
dissolved sulfate, calcium, strontium, or barium, magnesium, and iron ions, and to reduce
any substantial concentrations of borates, may obtain sufficiently treated water for use in
many common well-treatment operations. More preferably, any substantial concentration
of all of the dissolved sulfate, calcium, strontium, or barium, magnesium, and iron ions
would be desirable. Of course, the treated water according to the systems and methods of
the present invention would not be expected to be potable or suitable for other purposes.
Saving the cost of unnecessary water purification for use of the water in other well-
treatment operations, however, is expected to be of enormous economic and practical
benefit.
[0031] As used herein, the words "comprise," "has," and "include" and all
grammatical variations thereof are each intended to have an open, non-limiting meaning
that does not exclude additional elements or parts of an assembly, subassembly, or
structural element.
[0032] As used herein, the term "produced water" means brackish or saline water
produced from a subterranean well. If not specified, water to be treated can be of any
source, but is understood to not be suitable for well-treatment operations due to the
presence of a substantial concentration of any one or more of: calcium and magnesium
ions, iron ions; sulfate ions; and borate ions.
[0033] As used herein, the term "treated water" means and refers to water that has
been treated according to any one of the various treatment systems or methods according

to the invention, unless the context otherwise requires a reference to a specific stage or
step of the treatment systems or methods of the invention.
[0034] As used herein, the term "treatment stream" means a flow of liquid moving
continuously through any one of the treatment systems or methods according to the
invention, starting with a stream of water, moving through the system or method, and
ending with a stream of treated water.
[0035] As used herein, the terms "upstream" and "downstream" means with respect to
the movement of the treatment stream through a treatment or system or method according
to the invention, starting with a stream of water, moving "downstream" through the
system or method, and ending with a stream of treated water.
[0036] As used herein, the term "water soluble" means at least 0.1 mol/L in distilled
water when tested at standard temperature and pressure ("STP").
[0037] As used herein, a substantial concentration of sulfate ions is defined as being
equal to or greater than 500 ppm; a substantial concentration of calcium or magnesium
ions is defined as being equal to or greater than a combined total of 1,000 ppm; a
substantial concentration of iron ions is defined as being equal to or greater than 10 ppm;
a substantial concentration of borate is defined as being equal to or greater than 5 ppm.
[0038] If there is any conflict in the usages of a word or term in this specification and
one or more patent or other documents that may be incorporated herein by reference, the
definitions that are consistent with this specification should be adopted for the purposes
of understanding this invention.
[0039] According to the invention, a mobile water treatment system for sufficiently
treating water so that the treated water may be utilized in well-treatment operations is
provided. The system comprises:
(a) a mobile platform;
(b) an input pump, wherein the input pump is mounted on the mobile platform
and operatively connected to be capable of pumping a treatment stream through the
system;
(c) a centrifugal separator, wherein the centrifugal separator is mounted on
the mobile platform and operatively connected downstream of the input pump to
centrifugally treat the treatment stream;

(d) a borate filter, wherein the borate filter is mounted on the mobile platform
and operatively connected downstream of the centrifugal separator to filter the treatment
stream, and wherein the borate filter is capable of removing at least some of a borate that
may be present in the treatment stream when the treatment stream is at a pH of 8 or
above; and
(e) a chemical-additive subsystem, wherein the subsystem is mounted on the
mobile platform, and wherein the subsystem is operatively connected to be capable of:
(i) selectively adding one or more chemical agents to the treatment
stream upstream of the centrifugal separator, wherein the chemical agents can be selected
to be capable of precipitating dissolved ions selected from the group consisting of:
sulfate, calcium, strontium, or barium, magnesium, iron, and any combination thereof in
any proportion that may be present in the treatment stream; and
(ii) selectively adding a chemical agent to the treatment stream
upstream of the borate filter to increase the pH of the treatment stream to 8 or above,
wherein the pH increasing agent can be the same or different from one of the chemical
agents that can be selected to be capable of precipitating dissolved sulfate, calcium,
strontium, or barium, magnesium, or iron ions.
[0040] The chemical agents for adding to the treatment stream are selected from the
group consisting of: a water-soluble calcium, strontium, or barium halide; a water-soluble
carbonate; a water-soluble alkali metal hydroxide, and any combination thereof in any
proportion. The calcium, strontium, or barium halide is selected for reacting with and
precipitating sulfate ions as calcium, strontium, or barium sulfate, which is insoluble in
water. The carbonate is selected for reacting with and precipitating dissolved calcium
ions as calcium carbonate, which is insoluble in water. The hydroxide is selected for
reacting with and precipitating magnesium and iron ions as magnesium and iron
hydroxide, which are insoluble in water.
[0041 ] It should be understood, of course, that while these are the presently most
preferred classes of chemical agents that can be selected for these various purposes, these
are not necessarily the only classes that could be employed. For example, it is possible to
precipitate sulfate with ammonium hydroxide to obtain water-insoluble ammonium
sulfate precipitate, however, the use of ammonium compounds may create hazardous
conditions with possible release of ammonia gas to the atmosphere.

[0042] The insoluble salt precipitates may remain in the treatment stream as
suspended particulate. Downstream, at least some of this salt particulate, along with
other particulate in the treatment stream from the water, is expected to be centrifugally
removed from the treatment stream by the centrifugal separator.
[0043] The chemical agents for adding to the treatment stream preferably further
include a flocculating agent to assist in agglomerating particulate, including the
particulate caused by the precipitation of insoluble salts.
[0044] The chemical agent for increasing the pH of the treatment stream is selected to
be capable of increasing the pH of the treatment stream to at least 8. More preferably, the
pH increasing agent is selected to be capable of increasing the pH of the treatment fluid to
the range of about 8.5 -12. The pH increasing agent can be the same or different from
one of the chemical agents selected to be capable of precipitating dissolved sulfate,
calcium, strontium, or barium, magnesium, or iron ions.
[0045] In addition, it should be understood, of course, that it can be desirable to add
the chemical agents in a particular order to the treatment stream. For example, it can be
desirable to first add a chemical agent selected for being able to precipitate sulfate ions.
If a calcium, strontium, or barium halide is employed to precipitate the sulfate ions, it can
be desirable to add the carbonate downstream to precipitate calcium, strontium, or barium
ions in solution. This may be to allow some time for mixing and reaction of the calcium,
strontium, or barium halide with the dissolved sulfate ions prior to adding carbonate,
which would otherwise likely pull some of the calcium, strontium, or barium halide out of
solution in competition with the dissolved sulfate ions. By way of further example, if the
pH is not sufficiently high for the borate filtration step from the upstream addition of the
chemical agents employed for precipitating one or more of sulfate, calcium, strontium, or
barium, magnesium, or iron ions prior to the centrifugal separator, then additional or
different chemical agent can be added upstream of the borate filter for that purpose. In
this regard, the additional or separate pH increasing agent can optionally be added to the
treatment stream upstream of the centrifugal separator or anywhere between the
centrifugal separator and the borate filter.
[0046] Further, it should be understood that adding a chemical agent that is capable of
achieving at least some of a desired result or effect preferably includes that the chemical
agent is to be added in a sufficient concentration to achieve substantially all of the desired

result or effect. For example, a preferred concentration of calcium, strontium, or barium
halide to be added to the treatment stream for the purpose of precipitating at least some of
the dissolved sulfate ions in the treatment stream would be in the range of about 70% -
110% on a Molar basis of the concentration of sulfate ions in the treatment stream, and
more preferably in the range of about 90% -100% on a Molar basis. (The same is true
for achieving the desired effect of precipitating at least some of any of the other divalent
ions dissolved in the treatment stream, i.e., preferably a sufficient concentration of
chemical agent is added to the treatment stream such that substantially all of the particular
divalent ions dissolved in the treatment stream should be precipitated out of solution.)
Because calcium, strontium, or barium ion of the calcium, strontium, or barium halide is
itself a divalent ion, however, it is expected to be preferable not to use an excess of the
calcium, strontium, or barium halide. In the alternative, however, any excess of the
calcium, strontium, or barium ion concentration in the treatment stream from the addition
of calcium, strontium, or barium halide can be removed with the downstream addition of
sufficient carbonate.
[0047] Referring now to Figure 1 of the drawing, a system according to the
invention, generally referred to as the system 10, includes an input pump 12. The input
pump is mounted on the mobile platform (not shown in Figure 1) and operatively
connected to be capable of pumping a treatment stream through the system 10. The input
pump 12 can be operatively connected to draw water from a reservoir of water (not
shown in Figure 1), for example, via input piping 11 operatively connected to the input
pump. The output of the pump 12 is pumped downstream through pump outlet piping 13.
The input pump 12 should be a high-capacity pump, for example, capable of pumping up
to about 20 barrels per minute ("BPM").
[0048] According to the presently most-preferred embodiment of a system 10
according to the invention, a chemical-additive subsystem 14 preferably comprises at
least one liquid-additive pump, such as liquid-additive pump 14a, whereby various
chemical agents in aqueous solution can be added to the treatment stream. The liquid
additive pump 14a is relatively low capacity pumps compared to the input pump 12. For
example, the liquid-additive pump 14a can be capable of pumping up to about 40 gallons
per minute ("GPM"). According to the presently most-preferred embodiment of the
invention, the various chemical agents to be added to the treatment stream are preferably

dissolved in one or more aqueous solutions, which may be stored in one or more liquid
storage tanks (not shown in Figure 1). The liquid-additive pumps 14a can be operatively
connected to such liquid storage tanks for chemical agents with suitable piping 15a.
[0049] The chemical-additive subsystem 14 further comprises a means for mixing a
chemical agent with the treatment stream. Preferably, the means for mixing fluid streams
from the liquid-additive pump 14a comprises suitable liquid-additive piping 15b for
combining the liquid-additive streams with the treatment stream in piping 13. The means
for mixing the fluid streams from the liquid-additive pump 14a may further comprise
selectively operable valves (not shown in Figure 1) to assist in combining the various
fluid streams.
[0050] It should be understood by those of skill in the art that other types of
chemical-additive mechanisms could be used, and such are contemplated by the present
invention. For example, it is expected that solid chemical agents could be added using an
auger dispensing system into the balancing tank 16, which is for balancing fluid flows of
the treatment stream between the input pump 12 and the centrifugal separator 18.
[0051] Continuing to refer to Figure 1, the system 10 preferably further comprises a
balancing tank 16, According to the presently-preferred embodiment of system 10 shown
in Figure 1, the piping 13 directs the treatment stream to the balancing tank 16.
[0052] The balancing tank 16 is mounted on the mobile platform (not shown in
Figure 1) and operatively connected upstream of the centrifugal separator 18. The
balancing tank 16 helps balance the treatment stream from the input pump 12 in the
piping 13 into the balancing tank 16 with the treatment stream out of the balancing tank
16 via tank output piping 17 toward the centrifugal separator 18.
[0053] The balancing tank 16 should have sufficient volume to permit a non-uniform
flow of liquid to be collected, mixed, and moved downstream at a more uniform rate.
Pumping is controlled by level sensors in the balancing tank and the pumping rates varied
according to the depth of liquid in the balancing tank.
[0054] The contents of the balancing tank 16 are preferably mixed to prevent the
settlement of solids and to ensure that the liquid quality is as uniform as possible. To
prevent anaerobic conditions and odors developing in the balancing tank 16, the contents
of balancing tanks may need to be aerated. Venturi aerators can be used to mix and

aerate, while mixing propellers can be used to keep solids in suspension as the treatment
stream moves through the balancing tank 16.
[0055] In cases where the water contains a high concentration of solids, such as in a
mud, the system 10 may optionally include a shaker separator (not shown in Figure 1)
operatively connected upstream of the centrifugal separator 18. Preferably, the shaker
separator would be positioned upstream of the chemical-additive subsystem 14.
[0056] A shaker separator is well known in the oil and gas industry. A shaker
separator is based on the operating principle of a vibrating sieve. A wire-cloth screen
vibrates while a mud, such as a drilling fluid, flows on top of it. The liquid phase of the
mud and solids smaller than the wire mesh tend to pass through the vibrating screen,
while larger solids are retained on the screen. The vibrating screen is usually tilted
relative to the horizontal such that the larger solids fall off a side of the shaker separator.
Normally, the larger solids can be disposed of in a landfill without any further or special
treatment. The size of the openings in the vibrating screen remove more solids from the
whole mud, but decrease the flow rate per unit area of wire cloth.
[0057] Referring again to Figure 1 of the drawing, the system 10 further includes a
centrifugal separator 18. According to the presently-preferred embodiment of system 10
shown in Figure 1, the piping 17 directs the treatment stream to the centrifugal separator
18.
[0058] The purpose of the centrifugal separator 18 is to remove relatively large
particles from the treatment stream. Preferably, the centrifugal separator is capable of
removing at least 50% of the particles larger than 300 microns that may be in the
treatment stream. More preferably, the centrifugal separator is capable of removing at
least 50% of the particles larger than 100 microns that may be in the treatment stream. It
should be understood, of course, that the centrifugal separator can comprise a plurality of
centrifugal separators to achieve a desired capacity of fluid flow and effectiveness.
[0059] According to the presently preferred embodiment of the system, the
centrifugal separator 18 comprises a hydrocyclone 20, as illustrated in Figure 2. A
hydrocyclone is a well known type of centrifugal separator.
[0060] Referring briefly now to Figure 2, a hydrocyclone 20 is illustrated. The basic
operating principle of a hydrocyclone 20 is centrifugal force. Water containing solid
particulates is fed tangentially into the body 22 of the hydrocyclone 20. The inner wall

22a of the body 22 of the hydrocyclone 22 is in the shape of a cone with a smaller open
end or spigot 22b of the cone shape oriented downward. The tangentially fed water into
the body 22 of the hydrocyclone causes a vortex fluid flow 23. Internally of the induced
vertex fluid flow 23, the centrifugal force is countered by the resistance of the liquid, with
the effect that relatively larger or denser solid particulates tend to be thrown to the inner
wall 22a of the body 22 and to be discharged by gravity from the spigot 22b with a small
amount of water as underflow 23a. Most of the water containing relatively fine solid
particulates discharges from the upper end of the body 22 of the hydrocyclone 20 via the
vortex finder 22c as overflow 23b.
[0061] The underflow 23a of fluid from the spigot 22b of the hydrocyclone body 22
tends to contain particles coarser than the cut point size. Normally, the underflow 23a can
be disposed of in a disposal well or otherwise as may be practical.
[0062] The overflow 23b of fluid from the upper end of the hydrocyclone body 22
tends to contain relatively finer particles finer than the cut point size. The overflow 23b
from the hydrocyclone 20 continues through a system or method according to the
invention as part of the treatment stream. Referring back to Figure 1, output of the
centrifugal separator, for example the overflow 23b from a hydrocyclone 20, is directed
downstream through outlet piping 19 from the centrifugal separator 18.
[0063] The "cut point size" of a hydrocyclone should be clearly defined. As used
herein, for example, the term "d50 cut point" refers to the particle size at which the
hydrocyclone is 50% efficient at removing particles. The cut point size does not refer to
overflow products as this is dependant on the feed particle size analysis.
[0064] Preferably, the hydrocyclone 20 employed in a system or method according to
the invention should have a d50 cut point at least down to about 300 microns. More
preferably, the hydrocyclone should have a d50 cut point down to about 100 microns.
[0065] It should be understood, of course, that while the hydrocyclone is preferred,
based on the sizes, throughput capacity, and economics of such centrifugal separation
equipment, other types of centrifugal separators may be employed according to the
principles of the invention. For example, if a centrifuge is employed for the centrifugal
separator 18, a substantially dry cake of solid particulates is pulled out of the treatment
stream, which can normally be disposed of in a landfill.

[0066] Referring briefly now to Figure 3, a centrifuge 30 is illustrated. The basic
operating principle of a centrifuge 30 is centrifugal force. The centrifuge 30 is typically
supported horizontally on a frame 31. The body of the centrifuge defines a generally
cylindrical wall 32, and a screw-type conveyor 33. A relatively dirty water, sometimes
referred to as a mud, is fed into inlet 34, which flows through an opening in the conveyor
33 to the space between the conveyor 33 and the cylindrical wall 32, which space is
sometimes referred to as the bowl of the centrifuge. The rotation of the conveyor helps
separate the particulate from the fluid in a region 36 known as the drying zone and fluid
with a reduced particulate content moves through a liquid zone 37 toward outlet 38.
Caked mud is expelled through the outlet 39.
[0067] Both these types of centrifugal separators, the hydrocyclone 20 and the
centrifuge 30, are well known to those in such arts.
[0068] Referring again to Figure 1 of the drawing, the system 10 preferably further
includes a polish filter 40. According to the presently-preferred embodiment of system
10 shown in Figure 1, the piping 19 directs the treatment stream to the polish filter 40.
[0069] The polish filter is mounted on the mobile platform (not shown in Figure 1)
and operatively connected between the centrifugal separator 18 and a borate filter 50, and
wherein the polish filter 40 is capable of removing finer particulate sizes than the
centrifugal separator is capable of removing. Preferably, the polish filter 40 is capable of
removing particulate and precipitate sizes down to about 20 micron in size.
[0070] The polish filter 40 preferably has a mesh-bag as the filter media. More
preferably, the polish filter 40 comprises at least two polish filters operatively connected
in parallel, wherein centrifugally treated water is capable of being selectively directed
away from one polish filter so that the media of that polish filter can be replaced while
continuing to direct the stream of centrifugally treated water to one or more other polish
filters. This provides the benefit of being able to change a mesh-bag of a mesh-bag type
polish filter while continuing to pump the treatment stream through one or more other
mesh-bag type polish filters. A removed mesh bag with particulate accumulated therein
can normally be disposed of in a landfill.
[0071] According to another embodiment, the polish filter 40 comprises a
backflushable tube filter, preferably having at least two backflushable filtration tube
filters for being able to by-pass while backflushing one filtration tube to one or more

other backflushable filtration tubes. When a tube is backflushed, a liquid sludge is
produced that can be pumped down a disposal well or otherwise properly disposed of.
[0072] Output of the polish filter 40 is directed downstream through piping 41 toward
the borate filter 50.
[0073] Referring to Figure 1 of the drawing, the system 10 further includes a borate
filter 40. According to the presently-preferred embodiment of system 10 shown in
Figure 1, the piping 41 directs the treatment stream to the borate filter 50.
[0074] The borate filter 50 is mounted on the mobile platform (not shown in Figure
1) and operatively connected downstream of the centrifugal separator 18 to filter the
treatment stream. The borate filter 50 is capable of removing at least some of a borate
that may be present in the treatment stream when the treatment stream is at a pH of 8 or
above. More preferably, the pH of the treatment stream during passage through the
borate filter 50 is adjusted to be in the range of 8.5 -12.
[0075] Filter media that is capable of removing borate from the treatment stream
includes compounds that are capable of reacting with the borate. Such materials are
preferably in a solid, water-insoluble form that can be maintained in a filter vessel while
permitting the treatment stream to flow across the solid material, which should be placed
or formed as a water-permeable filter media. It is presently believed that the cis-diols of
cellulosic materials are ideal for labile addition of borate, which traps the borate with the
cellulose. Another solid, water-insoluble material that is well known for reacting with
borate is magnesium oxide.
[0076] The borate filter 50 preferably comprises a filter media comprising a cellulosic
material. In certain embodiments, the filter media may comprise a cellulose material, a
cellulose-based material, a cellulose material derived from cellulose pulp, and any
combination thereof in any proportion. Certain embodiments of the cellulose-based
material comprise a microcrystalline cellulose, a powdered or granular cellulose, a
colloidal cellulose, a surface-modified cellulose, or any insoluble cellulose. Certain
embodiments of the cellulose-based material may include chemically unmodified forms
of cellulose including, but not limited to, saw dust, wood shavings, and compressed wood
particles.
[0077] A removed filter media of cellulosic material with borate accumulated therein
can normally be disposed of in a landfill.

[0078] According to another embodiment of the invention, the borate filter 50 can
comprise a filter media wherein the filter media comprises magnesium oxide.
[0079] The borate filter 50 preferably comprises at least two borate filters operatively
connected in parallel, wherein centrifugally treated water is capable of being selectively
directed away from one borate filter so that the media of the borate filter can be replaced
while continuing to direct the stream of centrifugally treated water to one or more other
borate filters.
[0080] Additional information regarding an example of a filter and method of
filtration for removing borate from a fluid stream is disclosed in U.S. Patent Application
Publication Nos. US 2006/0186050 and US 2006/0186033, both published on August 24,
2006, and both having for named inventors Robert E. Hanes, David E. Griffin, and David
E. McMechan, each of which is incorporated herein by reference in its entirety.
[0081] Output of the borate filter 50 is directed downstream through piping 51 toward
a treated fluid storage reservoir.
[0082] Preferably, the system 10 further comprises a post-filtration chemical-additive
subsystem 60, wherein the post-filtration chemical-additive subsystem is mounted on the
mobile platform, and wherein the subsystem is operatively connected to be capable of:
selectively adding one or more chemical agents to the treatment stream downstream of
the borate filter 50 between the borate filter and a storage reservoir for treated fluid. The
chemical agents to be added downstream of the borate filter 50 can include, for example,
a neutralizing agent to substantially neutralize the pH of the treatment stream, a
bactericide, a surfactant, and any combination of the foregoing in any proportion.
[0083] According to the presently most-preferred embodiment of a system 10
according to the invention, a post borate-filter chemical-additive subsystem 60 preferably
comprises at least one liquid-additive pump, such as liquid-additive pump 60a, whereby
various chemical agents in aqueous solution can be added to the treatment stream. The
liquid additive pump 60a is a relatively low capacity pump compared to the input
pump 12. For example, the liquid-additive pump 50a can be capable of pumping up to
about 5 gallons per minute ("GPM"). According to the presently most-preferred
embodiment of the invention, the various chemical agents to be added to the treatment
stream downstream of the borate filter 50 are preferably dissolved in one or more aqueous
solutions, which may be stored in one or more liquid storage tanks (not shown in Figure

1). The liquid-additive pump 60a can be operatively connected to such liquid storage
tanks for chemical agents with suitable piping 61a.
[0084] The chemical-additive subsystem 60 further comprises a means for mixing a
chemical agent with the treatment stream. Preferably, the means for mixing fluid streams
from the liquid-additive pump 60a comprises suitable liquid-additive piping 61b for
combining the liquid-additive streams with the treatment stream in piping 41. The means
for mixing the fluid streams from the liquid-additive pump 60a can further comprise
selectively operable valves (not shown in Figure 1) to assist in combining the various
fluid streams.
[0085] Similar to the previous description with regard to the chemical-additive
subsystem 14, it should be understood by those of skill in the art that other types of
chemical-additive mechanisms could be used for the chemical-additive subsystem 50, and
such are contemplated by the present invention.
[0086] According to the invention, the system 10 preferably comprises appropriate
fluid conduits or piping, such as piping 11,13,15a, 15b, 17,19,41,51,61a, and 61b, for
operatively connecting together the various components of the system and for conducting
the treatment stream through a system or method according to the invention.
[0087] The mobile platform can be any suitable platform. For off-shore operations,
the mobile platform is a boat. For land-based operations, the mobile platform is a
wheeled platform. For example, referring now to Figures 4 and 5, the mobile platform
comprises at least one truck or trailer 70. Preferably, the mobile platform comprises one
or more trailers. Preferably, the trailer is a semi trailer having wheels in the rear and
adapted to be supported in the front by a towing vehicle when being moved. Preferably,
the mobile platform further includes a tractor for towing the trailer.
[0088] Continuing to refer now to Figures 4 and 5, the system can further comprise a
reservoir for produced water (or other water source) and a reservoir for treated water. A
reservoir can comprise, for example, a tank battery, a plurality of tank trucks or trailers, a
holding pit, a pond, and any combination thereof. As shown in Figure 4, the system can
include a plurality of mobile tank trucks 82 for brining produced water (or another "dirty"
water source) to an appropriate water treatment site, a trailer 70 for the water treatment
equipment of the system, and a plurality of holding tanks 84 for the temporary storage of
treated water, which is not necessarily potable but sufficiently "clean" for uses in well-

treatment operations. As shown in Figure 5, the system can include a plurality of tank
trucks 82 for bringing produced water (or other water source) to a holding pit 86a, a
trailer 70 for the water treatment equipment of the system, another holding pit 86b for the
temporary storage of treated water, and a plurality of tank trucks 82 for taking treated
water to a desired well location for use in well-treatment operations.
[0089] A method of water treatment for sufficiently treating water so that the treated
water may be utilized in well-treatment operations is provided. According to this aspect,
the method comprising the steps of: bringing a mobile water treatment system to a source
of water; and using the mobile water treatment system to treat water to obtain treated
water.
[0090] The method can further comprise the steps of: providing a reservoir for water,
and providing a reservoir for the treated water.
[0091] The method can further comprise the step of: using the treated water in a well-
treatment operation. As an example of a well-treatment operation which often requires a
very large quantity of water, the step of using the treated water in a well-treatment
operation can comprise fracturing a well. The systems and methods according the
invention would have particular application and practical beneficial use in such fracturing
operations.
[0092] According to another aspect of the invention, a method of water treatment for
sufficiently treating water so that the treated water may be utilized in well-treatment
operations is provided, wherein the method comprises the steps of:
(a) pumping water as part of a treatment stream;
(b) centrifugally removing at least some of the particulate that may be present
in the treatment stream;
(c) filtering out at least some of the borate that may be present in the treatment
stream with a filter media capable of removing a borate from the treatment stream at a pH
of 8 or above, wherein at least during the step of filtering of borate, the pH of the
treatment stream is or is adjusted to be 8 or above;
(d) adding a water-soluble calcium, strontium, or barium halide to the
treatment stream upstream of the centrifugally removing step, wherein the calcium,
strontium, or barium halide is capable of precipitating at least some of the sulfate ions
dissolved in the treatment stream as calcium, strontium, or barium sulfate; and

(e) adding a pH increasing agent to the treatment stream upstream of the
borate filtering step, wherein the pH increasing agent is capable of increasing the pH of
the treatment stream to at least 8.
[0093] This method preferably further includes the step of: adding a water-soluble
alkali metal hydroxide to the treatment stream upstream of the centrifugally removing
step, wherein the hydroxide is capable of precipitating at least some of the magnesium
and iron ions dissolved in the treatment stream as magnesium and iron hydroxide.
[0094] According to another aspect of the invention, a method of water treatment for
sufficiently treating water so that the treated water may be utilized in well-treatment
operations is provided, wherein the method comprises the steps of:
(a) pumping water as part of a treatment stream;
(b) centrifugally removing at least some of the particulate that may be present
in the treatment stream;
(c) filtering out at least some of the borate that may be present in the treatment
stream with a filter media capable of removing a borate from the treatment stream at a pH
of 8 or above, wherein at least during the step of filtering of borate, the pH of the
treatment stream is or is adjusted to be 8 or above;
(d) adding a water-soluble carbonate to the treatment stream upstream of the
centrifugally removing step, wherein the carbonate is capable of precipitating at least
some of the calcium ions dissolved in the treatment stream as calcium carbonate; and
(e) adding a pH increasing agent to the treatment stream upstream of the
borate filtering step, wherein the pH increasing agent is capable of increasing the pH of
the treatment stream to at least 8, and wherein the pH increasing agent can be the same or
different from the carbonate selected to be capable of precipitating dissolved calcium
ions.
[0095] This method preferably further includes the step of: adding a water-soluble
alkali metal hydroxide to the treatment stream upstream of the centrifugally removing
step, wherein the hydroxide is capable of precipitating at least some of the magnesium
and iron ions dissolved in the treatment stream as magnesium and iron hydroxide, and
wherein the pH increasing agent can be the same or different from the hydroxide selected
to be capable of precipitating dissolved magnesium and iron ions.

[0096] According to yet another aspect of the invention, a method of water treatment
for sufficiently treating water so that the treated water may be utilized in well-treatment
operations is provided, wherein the method comprises the steps of:
(a) pumping water as part of a treatment stream;
(b) centrifugally removing at least some of the particulate that may be present
in the treatment stream;
(c) filtering out at least some of the borate that may be present in the treatment
stream with a filter media capable of removing a borate from the treatment stream at a pH
of 8 or above, wherein at least during the step of filtering of borate, the pH of the
treatment stream is or is adjusted to be 8 or above;
(d) adding a water-soluble alkali metal hydroxide to the treatment stream
upstream of the centrifugally removing step, wherein the hydroxide is capable of
precipitating at least some of the magnesium and iron ions dissolved in the treatment
stream as magnesium and iron hydroxide; and
(e) adding a pH increasing agent to the treatment stream upstream of the
borate filtering step, wherein the pH increasing agent is capable of increasing the pH of
the treatment stream to at least 8, and wherein the pH increasing agent can be the same or
different from the carbonate selected to be capable of precipitating dissolved magnesium
and iron ions.
[0097] This method can further comprise the step of: adding a water-soluble calcium,
strontium, or barium halide to the treatment stream upstream of the centrifugally
removing step, wherein the calcium, strontium, or barium halide is capable of
precipitating at least some of the sulfate ions dissolved in the treatment stream as
calcium, strontium, or barium sulfate. Additionally or alternatively, this method can
further comprise the step of: adding a water-soluble carbonate to the treatment stream
upstream of the centrifugally removing step, wherein the carbonate is capable of
precipitating at least some of the calcium ions dissolved in the treatment stream as
calcium carbonate; and wherein the pH increasing agent can be the same or different from
the hydroxide selected to be capable of precipitating dissolved calcium ions.
[0098] According to still another aspect of the invention, a method of water treatment
for sufficiently treating water so that the treated water may be utili2ed in well-treatment
operations, wherein the method comprises the steps of:

(a) pumping water as part of a treatment stream;
(b) centrifugally removing at least some of the particulate that may be present
in the treatment stream; and
(c) filtering out at least some of the borate that may be present in the treatment
stream with a filter media capable of removing a borate from the treatment stream at a pH
of 8 or above, wherein at least during the step of filtering of borate, the pH of the
treatment stream is or is adjusted to be 8 or above;
(d) chemically treating the treatment stream, wherein the step of chemically
treating comprises at least one of the following steps:
(i) if sulfate is in any substantial concentration in the water, adding a
water-soluble calcium, strontium, or barium halide to the treatment stream upstream of
the centrifugally removing step, wherein the calcium, strontium, or barium halide is
capable of precipitating at least some of the sulfate ions dissolved in the treatment stream
as calcium, strontium, or barium sulfate;
(ii) if calcium is in any substantial concentration in the water, adding a
water-soluble carbonate to the treatment stream upstream of the centrifugally removing
step, wherein the carbonate is capable of precipitating at least some of the calcium ions
dissolved in the treatment stream as calcium carbonate;
(iii) if magnesium, iron, or any combination thereof is in any
substantial concentration in the water, adding a water-soluble alkali metal hydroxide to
the treatment stream upstream of the centrifugally removing step, wherein the hydroxide
is capable of precipitating at least some of the magnesium and iron ions dissolved in the
treatment stream as magnesium and iron hydroxide; and
(iv) if the pH of the treatment stream is not at least 8 or above at least
during the borate filtering step, adding a pH increasing agent to the treatment stream
upstream of the borate filtering step, wherein the pH increasing agent is capable of
increasing the pH of the treatment stream to at least 8, and wherein the pH increasing
agent can be the same or different from one of the chemical agents selected to be capable
of precipitating dissolved calcium, strontium, or barium, magnesium, or iron ions.
[0099] As described herein, any of the methods according to the invention preferably
further comprise the step of: chemically analyzing the treatment stream upstream of the
centrifugally removing step for the concentration of at least sulfate and calcium ions.

More preferably, the methods further include the step of chemically analyzing the
treatment stream for the concentrations of magnesium and iron ions. Most preferably, the
methods further include the step of chemically analyzing the treatment stream for the
concentration of borate. It can also be desirable to chemically analyze the treated water
to determine and confirm the effectiveness of the methods. Still further, the analyses can
also include particle size analyses. Such analytical information may also be useful to
help in troubleshooting and maintenance, for example, to determine when a filter media
should be replaced with fresh filter media.
[00100] The methods preferably further comprise the step of adding a
flocculating agent to the treatment stream upstream of the centrifugally removing step to
help agglomerate particulate prior to the centrifugally removing step.
[00101] The methods preferably further comprise the step of bringing a mobile
treatment system for practicing the steps of the method to a source of water or to a
reservoir of water.
[00102] The methods preferably further comprise the step of balancing the
treatment stream from the input pump with the treatment stream to the centrifugal
removing step.
[00103] In any of the methods according to the invention, the centrifugally
removing step preferably comprises using a hydrocyclone.
[00104] The methods preferably further comprise a step of polish filtering the
treatment stream between the centrifugally removing step and the borate filtering step,
wherein the polish filtering step removes finer sizes of particulate than the centrifugal
removing step.
[00105] In any of the methods, the borate filtering step preferably comprises
using a filter media comprising a water-insoluble cellulosic material. The cellulosic
material is preferably selected from the group consisting of: a cellulose-based material, a
cellulose material derived from cellulose pulp, and any combination thereof in any
proportion.
[00106] The methods preferably further comprise the steps of: providing a
reservoir for water, and providing a reservoir for the treated water.

[00107] The methods preferably further comprise the step of: using the treated
water in a well-treatment operation. The step of using the treated water in a well-
treatment operation comprises: fracturing a well.
[00108] It should be understood, of course, that two or more of the various
preferred elements or steps of the invention are more advantageously practiced together
to increase the efficiency and benefits that can be obtained from the invention.
[00109] Thus, the present invention is well adapted to carry out the objects and
attain the ends and advantages mentioned above as well as those inherent therein. While
preferred embodiments of the invention have been described for the purpose of this
disclosure, changes in the construction and arrangement of parts and the performance of
steps can be made by those skilled in the art, which changes are encompassed within the
spirit of this invention as defined by the appended claims.

What is claimed is:
1. A method of water treatment for sufficiently treating water so that the treated water
may be utilized in well-treatment operations, the method comprising the steps of:
(a) pumping water as part of a treatment stream;
(b) centrifugally removing at least some of the particulate that may be present
in the treatment stream; and
(c) filtering out at least some of the borate that may be present in the treatment
stream with a filter media capable of removing a borate from the treatment stream at a pH
of 8 or above, wherein at least during the step of filtering of borate, the pH of the
treatment stream is or is adjusted to be 8 or above;
(d) chemically treating the treatment stream, wherein the step of chemically
treating comprises at least one of the following steps:
(i) adding a water-soluble calcium, strontium, or barium halide to the
treatment stream upstream of the centrifugally removing step, wherein the calcium,
strontium, or barium halide is capable of precipitating at least some of the sulfate ions
dissolved in the treatment stream as calcium, strontium, or barium sulfate;
(ii) adding a water-soluble carbonate to the treatment stream upstream
of the centrifugally removing step, wherein the carbonate is capable of precipitating at
least some of the calcium ions dissolved in the treatment stream as calcium carbonate;
(iii), adding a water-soluble alkali metal hydroxide to the treatment
stream upstream of the centrifugally removing step, wherein the hydroxide is capable of
precipitating at least some of the magnesium and iron ions dissolved in the treatment
stream as magnesium and iron hydroxide; and
(iv) adding a pH increasing agent to the treatment stream upstream of
the borate filtering step, wherein the pH increasing agent is capable of increasing the pH
of the treatment stream to at least 8, and wherein the pH increasing agent can be the same
or different from one of the chemical agents selected to be capable of precipitating
dissolved calcium, strontium, or barium, magnesium, or iron ions.

2. A method of water treatment for sufficiently treating water so that the treated water
may be utilized in well-treatment operations, the method comprising the steps of:
(a) pumping water as part of a treatment stream;
(b) centrifugally removing at least some of the particulate that may be present
in the treatment stream;
(c) filtering out at least some of the borate that may be present in the treatment
stream with a filter media capable of removing a borate from the treatment stream at a pH
of 8 or above, wherein at least during the step of filtering of borate, the pH of the
treatment stream is or is adjusted to be 8 or above;
(d) adding a water-soluble calcium, strontium, or barium halide to the
treatment stream upstream of the centrifugally removing step, wherein the calcium,
strontium, or barium halide is capable of precipitating at least some of the sulfate ions
dissolved in the treatment stream as calcium, strontium, or barium sulfate; and
(e) adding a pH increasing agent to the treatment stream upstream of the
borate filtering step, wherein the pH increasing agent is capable of increasing the pH of
the treatment stream to at least 8.

3. The method according to Claim 2, further comprising the step of: adding a water-
soluble alkali metal hydroxide to the treatment stream upstream of the centrifugally
removing step, wherein the hydroxide is capable of precipitating at least some of the
magnesium and iron ions dissolved in the treatment stream as magnesium and iron
hydroxide.
4. A method of water treatment for sufficiently treating water so that the treated water
may be utilized in well-treatment operations, the method comprising the steps of:

(a) pumping water as part of a treatment stream;
(b) centrifugally removing at least some of the particulate that may be present
in the treatment stream;
(c) filtering out at least some of the borate that may be present in the treatment
stream with a filter media capable of removing a borate from the treatment stream at a pH
of 8 or above, wherein at least during the step of filtering of borate, the pH of the
treatment stream is or is adjusted to be 8 or above;

(d) adding a water-soluble carbonate to the treatment stream upstream of the
centrifugally removing step, wherein the carbonate is capable of precipitating at least
some of the calcium ions dissolved in the treatment stream as calcium carbonate; and
(e) adding a pH increasing agent to the treatment stream upstream of the
borate filtering step, wherein the pH increasing agent is capable of increasing the pH of
the treatment stream to at least 8, and wherein the pH increasing agent can be the same or
different from the carbonate selected to be capable of precipitating dissolved calcium
ions.

5. The method according to Claim 4, further comprising the step of: adding a water-
soluble alkali metal hydroxide to the treatment stream upstream of the centrifugally
removing step, wherein the hydroxide is capable of precipitating at least some of the
magnesium and iron ions dissolved in the treatment stream as magnesium and iron
hydroxide, and wherein the pH increasing agent can be the same or different from the
hydroxide selected to be capable of precipitating dissolved magnesium and iron ions.
6. A method of water treatment for sufficiently treating water so that the treated water
may be utilized in well-treatment operations, the method comprising the steps of:

(a) pumping water as part of a treatment stream;
(b) centrifugally removing at least some of the particulate that may be present
in the treatment stream;
(c) filtering out at least some of the borate that may be present in the treatment
stream with a filter media capable of removing a borate from the treatment stream at a pH
of 8 or above, wherein at least during the step of filtering of borate, the pH of the
treatment stream is or is adjusted to be 8 or above;
(d) adding a water-soluble alkali metal hydroxide to the treatment stream
upstream of the centrifugally removing step, wherein the hydroxide is capable of
precipitating at least some of the magnesium and iron ions dissolved in the treatment
stream as magnesium and iron hydroxide; and
(e) adding a pH increasing agent to the treatment stream upstream of the
borate filtering step, wherein the pH increasing agent is capable of increasing the pH of
the treatment stream to at least 8, and wherein the pH increasing agent can be the same or

different from the carbonate selected to be capable of precipitating dissolved magnesium
and iron ions.
7. The method according to Claim 6, further comprising the step of: adding a water-
soluble calcium, strontium, or barium halide to the treatment stream upstream of the
centrifugally removing step, wherein the calcium, strontium, or barium is capable of
precipitating at least some of the sulfate ions dissolved in the treatment stream as
calcium, strontium, or barium sulfate.
8. The method according to Claim 6, further comprising the step of: adding a water-
soluble carbonate to the treatment stream upstream of the centrifugally removing step,
wherein the carbonate is capable of precipitating at least some of the calcium ions
dissolved in the treatment stream as calcium carbonate; and wherein the pH increasing
agent can be the same or different from the hydroxide selected to be capable of
precipitating dissolved calcium ions.
9. The method according to Claim 1, further comprising the step of: chemically
analyzing the water for the concentration of at least sulfate and calcium, ions.

10. The method according to Claim 1, further comprising the step of adding a
flocculating agent to the treatment stream upstream of the centrifugally removing step to
help agglomerate particulate prior to the centrifugally removing step.
11. The method according to Claims 1, further comprising the step of bringing a mobile
treatment system for practicing the steps of the method to a source of water.
12. The method according to Claim 1, further comprising the step of balancing the
treatment stream from the input pump with the treatment stream to the centrifugal
removing step.
13. The method according to Claim 1, wherein the centrifugally removing step comprises
using a hydrocyclone.

14. The method according to Claim 1, further comprising a step of polish filtering the
treatment stream between the centrifugally removing step and the borate filtering step,
wherein the polish filtering step removes finer sizes of particulate than the centrifugal
removing step.
15. The method according to Claim 1, wherein the borate filtering step comprises using a
filter media comprising a water-insoluble cellulosic material.
16. The method according to Claim 15, wherein the cellulosic material is selected from
the group consisting of: a cellulose-based material, a cellulose material derived from
cellulose pulp, and any combination thereof in any proportion.
17. The method according to Claim 1, further comprising the steps of: providing a
reservoir for water, and providing a reservoir for the treated water.
18. The method according to Claim 1, further comprising the step of: using the treated
water in a well-treatment operation.
19. The method according to Claim 18, wherein the step of using the treated water in a
well-treatment operation comprises: fracturing a well.
20. A mobile water treatment system for sufficiently treating water so that the treated
water may be utilized in well-treatment operations, the system comprising:
(a) a mobile platform;
(b) an input pump, wherein the input pump is mounted on the mobile platform and
operatively connected to be capable of pumping a treatment stream through the system;
(c) a centrifugal separator, wherein the centrifugal separator is mounted on the
mobile platform and operatively connected downstream of the input pump to
centrifugally treat the treatment stream;
(d) a borate filter, wherein the borate filter is mounted on the mobile platform and
operatively connected downstream of the centrifugal separator to filter the treatment

stream, and wherein the borate filter is capable of removing at least some of a borate that
may be present in the treatment stream when the treatment stream is at a pH of 8 or
above; and
(e) a chemical-additive subsystem, wherein the subsystem is mounted on the mobile
platform, and wherein the subsystem is operatively connected to be capable of:
(i) selectively adding one or more chemical agents to the treatment stream
upstream of the centrifugal separator, wherein the chemical agents can be selected to be
capable of precipitating dissolved ions selected from the group consisting of: sulfate,
calcium, strontium, or barium, magnesium, iron, and any combination thereof in any
proportion that may be present in the treatment stream; and
(ii) selectively adding a chemical agent to the treatment stream upstream of the
borate filter borate filter to increase the pH of the treatment stream to 8 or above, wherein
the pH increasing agent can be the same or different from one of the chemical agents that
can be selected to be capable of precipitating dissolved sulfate, calcium, strontium, or
barium, magnesium, or iron ions.

A system is provided that includes: (a) a mobile platform; (b) an input pump operatively connected to be capable
of pumping a treatment stream through the system; (c) a centrifugal separator operatively connected downstream of the input pump
to centrifugally treat the treatment stream; (d) a borate filter operatively connected downstream of the centrifugal separator to filter
the treatment stream capable of removing at least some of a borate when the treatment stream is at a pH of 8 or above; and (e)
a chemical-additive subsystem operatively connected to be capable of: (i) selectively adding one or more chemical agents to the
treatment stream upstream of the centrifugal separator, wherein the chemical agents can be selected to be capable of precipitating
dissolved ions selected from the group consisting of: sulfate, calcium, strontium, or barium, magnesium, iron; and (ii) selectively
adding a chemical agent to the treatment stream upstream of the borate filter to increase the pH of the treatment stream to 8 or above.