WELL TOOL ASSEMBLIES WITH QUICK CONNECTORS AND
SHOCK MITIGATING CAPABILITIES
TECHNICAL FIELD
The present disclosure relates generally to equipment
utilized and operations performed in conjunction with
subterranean wells and, in an embodiment described herein,
more particularly provides a well tool assembly with quick
connectors and shock mitigating capabilities.
BACKGROUND
Shock absorbers have been used in the past in attempts
to prevent damage to well equipment resulting from firing
perforating guns and other events. In some situations, a
shock absorber is interconnected between a perforating
assembly and the well equipment (such as, a packer, gravel
packing equipment, instruments, etc.) to be protected from
shock loads.
However, testing has revealed that such shock loads are
transmitted in a very short amount of time (e.g., -10-30
milliseconds), and conventional shock absorbers are either
too rigid to react adequately to the shock, or too compliant
to absorb the shock. Therefore, it will be appreciated that
improvements are needed in the art of mitigating shock for
well assemblies.
Improvements are also needed in the art of connecting
well tool assemblies. Such improvements could reduce the
amount of time needed to connect perforating devices or
other well tools, and could prevent damage to connectors
used to connect well tools.
SUMMARY
In carrying out the principles of the present
disclosure, systems and methods are provided which bring
improvements to the art. One example is described below in
which multiple shock absorbers are interconnected in a
perforating assembly. Another example is described below in
which connections are made between well tools without
threading .
A method described below can include interconnecting a
well tool in a well tool assembly with a shock mitigating
connection, the interconnecting being performed without
threading, and positioning the well tool assembly in a
wellbore. The method may be used for well perforating
assemblies, or for other types of well tool assemblies.
In one aspect, a well perforating assembly is
disclosed. The perforating assembly can include at least two
perforating devices, a detonation train extending through
the perforating devices, and a shock absorber positioned
between the perforating devices.
In another aspect, a method of assembling a perforating
assembly is described below. The method can include, prior
to installing the perforating assembly in a wellbore,
pushing one perforating device connector into another
perforating device connector without threading the
connectors together, thereby: a ) preventing disconnection of
the connectors and b ) making a connection in a detonation
train .
In yet another aspect, a well system is provided which
can include a perforating assembly including multiple
perforating guns and multiple shock absorbers. Each shock
absorber is interconnected between at least two of the
perforating guns.
These and other features, advantages and benefits will
become apparent to one of ordinary skill in the art upon
careful consideration of the detailed description of
representative embodiments of the disclosure hereinbelow and
the accompanying drawings, in which similar elements are
indicated in the various figures using the same reference
numbers .
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a representative partially cross-sectional
view of a well system and associated method which can embody
principles of the present disclosure.
FIG. 2 is an enlarged scale representative partially
cross-sectional view of a prior art perforating assembly.
FIG. 3 is a representative cross-sectional view of a
perforating assembly which can embody principles of this
disclosure .
FIG. 4 is a further enlarged scale cross-sectional view
of detail 4 in FIG. 3 .
FIG. 5 is a still further enlarged scale crosssectional
view of detail 5 in FIG. 4 .
FIG. 6 is a representative partially cross-sectional
view of another configuration of the well system and method.
DETAILED DESCRIPTION
Representatively illustrated in FIG. 1 is a well system
10 and associated method which can embody principles of the
present disclosure. In the system 10, a perforating assembly
12 is positioned in a wellbore 14 for forming perforations
16 through casing 18 lining the wellbore.
The perforating assembly 12 can include any number of
perforating devices, such as a firing head 20 and
perforating guns 22. The firing head 20 fires the
perforating guns 22 in response to a particular stimulus
(e.g., pressure levels, pressure pulses, a telemetry signal,
a bar dropped through a tubular string to the firing head,
etc.). Any type of firing head, and any type of perforating
guns, may be used in the perforating assembly 12 in keeping
with the principles of this disclosure.
Although only one firing head 20 connected above the
perforating guns 22 is depicted in FIG. 1 , it will be
appreciated that any number or position of firing head(s)
may be used, as desired. For example, the firing head 20
could be connected at a lower end of the perforating
assembly 12, multiple firing heads could be used, a separate
firing head could be used for each perforating gun, etc.
In the system 10, it is desired to prevent unsetting or
otherwise damaging a packer 24 set in the casing 18 above
the perforating guns 22. The packer 24 is used herein as one
example of a type of well equipment which can be protected
using the principles of this disclosure, but it should be
clearly understood that any other types of well equipment
(e.g., anchors, hangers, instruments, other perforating
devices, etc.) may be protected in other examples.
In one unique feature of the well system 10, a shock
absorbing connection 26 is disposed between each adjacent
pair of the perforating guns 22, and a shock absorbing
connection is also disposed between the firing head 20 and
the uppermost perforating gun. The connections 26 also allow
the perforating devices (firing head 20 and perforating guns
22) to be quickly assembled to each other prior to
installing the perforating assembly 12 in the wellbore 14.
Although a connection 26 is depicted in FIG. 1 between
each adjacent pair of the perforating guns 22, it will be
appreciated that the connections could be otherwise
positioned. In other examples, some adjacent pairs of
perforating guns 22 may not have the connections 26 between
them. Thus, it is not necessary for each adjacent pair of
perforating guns 22 to have one of the connections 26
between them, nor is it necessary for one of the connections
26 to be positioned between the firing head 20 and the
adjacent perforating gun 22.
By interconnecting multiple shock absorbing connections
26 in the perforating assembly 12, each connection only has
to absorb shock generated due to firing of the adjacent
perforating device(s), and accumulation of the shock loads
along the perforating assembly is prevented, or at least
beneficially mitigated. Greater or fewer numbers of the
connections 26 may be used in the perforating assembly 12 as
needed to achieve a desired level of shock mitigation.
Referring additionally now to FIG. 2 , a partially
cross-sectional view of a prior art perforating assembly 28
is representatively illustrated. The perforating assembly 28
includes the perforating guns 22, with each perforating gun
including perforating charges 30, a charge carrier 32 and
detonating cord 34 in a generally tubular gun body 36.
However, instead of the shock absorbing connections 26
used in the system 10, the perforating assembly 28 of FIG. 2
includes a rigid, threaded connection 38 between the
perforating guns 22. Specifically, a connector 40 having
opposing externally-threaded ends is threaded into one
perforating gun 22, and another connector 42 having opposing
externally- and internally-threaded ends is threaded into
another perforating gun 22.
When the connectors 40, 42 are threaded together, the
rigid, threaded connection 38 is made. The connection 38 has
no shock absorbing capability, and threading the connectors
40, 42 to each other can be difficult when the guns 22 are
long and/or heavy, sometimes resulting in damage to threads
on the connectors .
The improved connection 26 used in the system 10 is
representatively illustrated in FIG. 3 . The connection 26
may be used between perforating guns 22, between a
perforating gun and the firing head 20, or between any other
well tools or equipment. The connection 26 may also be used
in perforating assemblies other than the perforating
assembly 12, and in well systems other than the well system
10, in keeping with the principles of this disclosure.
The connection 26 includes a connector 44 which is
attached to a perforating device (such as a perforating gun
or firing head, not shown), and another connector 46 which
is depicted in FIG. 3 as being attached to a perforating gun
22. The connectors 44, 46 may each be attached to the
respective perforating guns 22, firing head 20 or other
perforating devices or other well tools by threading or any
other suitable means.
In one unique feature of the connection 26, the
connector 44 can be inserted and pushed into the other
connector 46 without threading. Once connected in this
manner, an engagement device 48 prevents disconnection of
the connectors 44, 46.
The engagement device 48 permits the connector 44 to
displace in one direction longitudinally toward the other
connector 46, but prevents the connector 44 from displacing
in the opposite longitudinal direction relative to the
connector 46. Thus, the connection 26 can be longitudinally
compressed, but the device 48 prevents the connection from
being elongated longitudinally.
One benefit of this arrangement is that the perforating
devices or other well tools attached to the connectors 44,
46 can be quickly and conveniently connected to each other,
without any need for threading the connector 44 into the
other connector 46. Another benefit of this arrangement is
that detonation transfer components (such as, detonation
boosters 56 attached at ends of the detonating cords 34) are
brought into close proximity to each other when the
connector 44 is pushed into the other connector 46. In this
manner, a connection is made in a detonation train 54
(including the detonating cord 34, boosters 56, etc.) which
extends through the connection 26.
Another unique feature of the connection 26 is that it
includes shock absorbers 50, 52 disposed between the
connectors 44, 46. The shock absorbers 50, 52 function to
absorb shock loads which would otherwise be transmitted
through the connection 26.
The shock absorbers 50, 52 are preferably made of a
material which can deform appropriately to absorb the shock
loads resulting from firing of the perforating devices. Some
acceptable materials for the shock absorbers 50, 52 can
include brass, aluminum, rubber, foamed materials, or any
other shock absorbing materials.
The shock absorbers 50, 52 may be annular-shaped as
depicted in FIG. 3 , or they could have any other shapes,
such as round, square, T- or I-shaped cross-sections, etc.
The size, shape, material and/or other characteristics of
the shock absorbers 50, 52 may be customized for their
placement in the perforating assembly 12, position in the
well, size and length of the adjacent perforating devices or
other well tools, etc.
Although two shock absorbers 50, 52 are illustrated in
the connection 26 example of FIG. 3 , in other examples
different numbers of shock absorbers (including one) may be
used. In addition, although in FIG. 3 the detonation train
54 is depicted as extending through the shock absorbers 50,
52, such an arrangement is not necessary in keeping with the
principles of this disclosure.
Since the connection 26 allows for longitudinal
compression of the connectors 44, 46, when a compressive
shock load is transmitted to the connection, the connectors
will compress somewhat, with the shock absorbers 50, 52
thereby absorbing the compressive shock load. In this
manner, transmission of the shock load across the connection
26 is prevented, or is at least significantly mitigated.
Referring additionally now to FIG. 4 , an enlarged scale
cross-sectional view of the engagement device 48 is
representatively illustrated. As depicted in FIG. 4 , the
engagement device 48 comprises a segmented or longitudinally
split sleeve 58 having a series of relatively coarse pitch
ramp-type profiles 60 on an exterior thereof, and a series
of relatively fine pitch profiles 62 on an interior thereof.
The profiles 6 0 , 6 2 may be formed as threads on the
engagement device 4 8 , with the respective connectors 4 6 , 4 4
having complementarily shaped profiles formed thereon. For
example, the profiles 6 0 could be formed as 4 5-degree
buttress threads, and the profiles 6 2 could be formed as a
"phonograph" finish (very fine grooves).
However, it should be understood that, preferably, the
connectors 4 4 , 4 6 are not threaded to each other with the
engagement device 4 8 . Instead, the connector 4 4 is
preferably pushed into the connector 4 6 (without rotating or
threading either connector), and the engagement device 4 8
prevents the connector 4 4 from being withdrawn from the
connector 4 6 .
In the example of FIG. 4 , this result is accomplished
due to the ramped interface between the profiles 6 0 and the
connector 4 6 , and gripping of the connector 4 4 by the
profiles 6 2 . A further enlarged scale view of this
engagement between the connectors 4 4 , 4 6 and the device 4 8
is representatively illustrated in FIG. 5 .
If a tensile load is applied across the connection 2 6 ,
the profiles 6 2 will grip the outer surface of the connector
4 4 , so that the sleeve 5 8 attempts to displace with the
connector 4 4 . However, the ramps of the profiles 6 0 , in
engagement with the connector 4 6 , prevent downward (as
viewed in FIG. 5 ) displacement of the connector 4 4 and
sleeve 5 8 , and cause the sleeve to be compressed radially
inward.
The inward compression of the sleeve 5 8 causes the
profiles 6 2 to more securely grip the outer surface of the
connector 4 4 . The sleeve 5 8 can be formed with a C-shaped
lateral cross-section, so that it can be readily deformed
inward. The sleeve 5 8 can also be deformed radially outward,
if desired, so that it no longer grips the outer surface of
the connector 44, thereby allowing the connector 44 to be
withdrawn from the connector 46, for example, to disassemble
the perforating assembly 12 after firing, after a misfire,
etc .
Although the connection 26 is described above as having
multiple benefits (e.g., speed of connecting, lack of
threading connectors 44, 46 to each other, shock absorbing
capability, detonation train 54 connecting, etc.), it is not
necessary for all of the above-described benefits to be
incorporated into a single connection embodying principles
of this disclosure. The connection 26 could include one of
the above-described benefits, any subset of those benefits,
and/or other benefits.
Referring additionally now to FIG. 6 , another
configuration of the well system 10 is representatively
illustrated. In this configuration, the connections 26 are
used to prevent or mitigate shock being transmitted to
various well tools 64a-c interconnected in a well tool
assembly 66 positioned in the wellbore 14.
In this example, the well tool 64a comprises an
instrument carrier (containing, for example, one or more
pressure and/or temperature sensors, etc.), the well tool
64b comprises a fluid sampler (e.g., with chambers therein
for containing selectively filled fluid samples), and the
well tool 64c comprises an electronics module (e.g., used
for receiving, storing and/or transmitting data, commands,
etc., measuring parameters, etc.). However, it should be
clearly understood that these are merely examples of well
tools which can benefit from the principles of this
disclosure, and any type of well tool may be used in the
assembly 66 in keeping with those principles.
It is not necessary for the assembly 66 to include
multiple well tools. Instead, a single well tool may benefit
from use of the connections 26.
It is not necessary for the connections 26 to be used
on both ends of each of the well tools 64a-c as depicted in
FIG. 6 . Instead, a connection 26 may be used on only one end
of a well tool, or in positions other than the ends of a
well tool.
In the example of FIG. 6 , the connections 26 prevent or
mitigate shock being transmitted to the well tools 64a-c
interconnected in the assembly 66, and also allow the well
tools to be interconnected in the assembly quickly and
without threading. Note that the firing head 20, perforating
guns 22 and packer 24 described above are also examples of
well tools which can benefit from use of the connection 26.
It may now be fully appreciated that the above
disclosure provides several advancements to the art. The
connection 26 depicted in FIGS. 1 & 3-6 allows for shock
loads to be absorbed or at least mitigated between
perforating devices or other well tools, and allows
perforating devices and other well tools to be connected to
each other quickly and without threading.
A method described above can include interconnecting a
well tool 64a-c in a well tool assembly 66 with a shock
mitigating connection 26, the interconnecting being
performed without threading, and positioning the well tool
assembly 66 in a wellbore 14.
The connection 26 may comprise at least one shock
absorber 50, 52 positioned between connectors 44, 46. The
connection 26 may comprise a sleeve 58 having relatively
coarse pitch profiles 60 on one side, and the sleeve 58
having relatively fine pitch profiles 62 on an opposite
side .
Interconnecting can include pushing one connector 44
into another connector 46 without threading the connectors
44, 46 together, thereby preventing disconnection of the
connectors 44, 46. An engagement device 48 may permit
relative displacement between the connectors 44, 46 in one
longitudinal direction, but prevent relative displacement
between the connectors 44, 46 in an opposite longitudinal
direction.
The well tool may be one or more of a perforating gun
22, a firing head 20, a packer 24, an instrument carrier
64a, a fluid sampler 64b and an electronics module 64c.
A well perforating assembly 12 described above can
include at least two perforating devices (such as firing
head 20, perforating gun 22, etc.), a detonation train 54
extending through the perforating devices 20, 22, and a
shock absorber 50, 52 positioned between the perforating
devices 20, 22.
The shock absorber 50, 52 preferably absorbs
longitudinally directed shock generated by firing at least
one of the perforating devices 20, 22.
The detonation train 54 may extend longitudinally
through the shock absorber 50, 52.
The perforating devices may comprise perforating guns
22. The perforating devices may comprise a perforating gun
22 and a firing head 20.
The assembly 12 can include a connection 26 between the
perforating devices 20, 22. An engagement device 48 of the
connection 26 may permit longitudinal compression of the
connection 26, but prevent elongation of the connection 26.
The connection 26 can comprise connectors 44, 46
attached to the respective perforating devices. The
engagement device 48 may permit relative displacement
between the connectors 44, 46 in one longitudinal direction,
but prevent relative displacement between the connectors 44,
46 in an opposite longitudinal direction.
The connectors 44, 46 are preferably connected to each
other without threading together the connectors 44, 46. The
detonation train 54 may extend through the connectors 44,
46.
Also described above is a method of assembling a
perforating assembly 12. The method can include, prior to
installing the perforating assembly 12 in a wellbore 14,
pushing one perforating device connector 44 into another
perforating device connector 46 without threading the
connectors 44, 46 together, thereby: a ) preventing
disconnection of the connectors 44, 46 and b ) making a
connection in a detonation train 54.
The method can also include positioning a shock
absorber 50, 52 between the connectors 44, 46. The shock
absorber 50, 52 may absorb longitudinally directed shock
generated by firing at least one perforating device 20, 22.
The detonation train 54 may extend longitudinally through
the shock absorber 50, 52.
Each, or at least one, of the perforating device
connectors 44, 46 may be attached to a perforating gun 22.
At least one of the perforating device connectors 44, 46 may
be attached to a firing head 20.
The above disclosure also provides to the art a well
system 10. The well system 10 can comprise a perforating
assembly 12 including multiple perforating guns 22 and
multiple shock absorbers 50, 52.
Each shock absorber 50, 52 may be interconnected
between at least two of the perforating guns 22. Each shock
absorber 50, 52 preferably mitigates transmission of shock
from one connector 44 to another 46, the connectors being
longitudinally compressible but prevented from elongating. A
detonation train 54 may extend through the shock absorbers
50, 52.
It is to be understood that the various embodiments of
the present disclosure described herein may be utilized in
various orientations, such as inclined, inverted,
horizontal, vertical, etc., and in various configurations,
without departing from the principles of the present
disclosure. The embodiments are described merely as examples
of useful applications of the principles of the disclosure,
which is not limited to any specific details of these
embodiments .
In the above description of the representative
embodiments of the disclosure, directional terms, such as
"above," "below," "upper," "lower," etc., are used merely
for convenience in referring to the accompanying drawings.
Of course, a person skilled in the art would, upon a
careful consideration of the above description of
representative embodiments of the disclosure, readily
appreciate that many modifications, additions,
substitutions, deletions, and other changes may be made to
the specific embodiments, and such changes are contemplated
by the principles of the present disclosure. Accordingly,
the foregoing detailed description is to be clearly
understood as being given by way of illustration and example
only, the spirit and scope of the present invention being
limited solely by the appended claims and their equivalents.

WE CLAIM:
1. A method, comprising:
interconnecting a well tool in a well tool assembly with a shock mitigating
connection, the interconnecting being performed without threading; and
positioning the well tool assembly in a wellbore.
2. A method as claimed in claim 1, wherein the connection comprises at least
one shock absorber positioned between connectors.
3. A method as claimed in claim 1, wherein the connection comprises a
sleeve having relatively coarse pitch profiles on one side, and the sleeve having
relatively fine pitch profiles on an opposite side.
4. A method as claimed in claim 1, wherein interconnecting comprises
pushing one connector into another connector without threading the connectors
together, thereby preventing disconnection of the connectors.
5. A method as claimed in claim 4, wherein an engagement device permits
relative displacement between the connectors in one longitudinal direction, but
prevents relative displacement between the connectors in an opposite
longitudinal direction.
6. A method as claimed in claim 1, wherein the well tool is selected from a
group comprising: a perforating gun, a firing head, a packer, an instrument
carrier, a fluid sampler and an electronics module.
-14-
7. A well perforating assembly, comprising:
at least two perforating devices;
a detonation train extending through the perforating devices; and
a shock absorber positioned between the perforating devices.
8. An assembly as claimed in claim 7, wherein the shock absorber absorbs
longitudinally directed shock generated by firing at least one of the perforating
devices.
9. An assembly as claimed in claim 7, wherein the detonation train extends
longitudinally through the shock absorber.
10. An assembly as claimed in claim 7, wherein the perforating devices
comprise perforating guns.
11. An assembly as claimed in claim 7, wherein the perforating devices
comprise a perforating gun and a firing head.
12. An assembly as claimed in claim 7, further comprising a connection
between the perforating devices, and wherein an engagement device of the
connection permits longitudinal compression of the connection, but prevents
elongation of the connection.
13. An assembly as claimed in claim 12, wherein the connection comprises
connectors attached to the respective perforating devices, and wherein the
engagement device permits relative displacement between the connectors in one
-15-
- •
longitudinal direction, but prevents relative displacement between the connectors
in an opposite longitudinal direction.
14. An assembly as claimed in claim 13, wherein the connectors are
connected to each other without threading together the connectors.
15. An assembly as claimed in claim 13, wherein the detonation train extends
through the connectors.
16. A method of assembling a perforating assembly, the method comprising:
prior to installing the perforating assembly in a wellbore, pushing one
perforating device connector into another perforating device connector without
threading the connectors together, thereby: a) preventing disconnection of the
connectors and b) making a connection in a detonation train.
17. A method as claimed in claim 16, further comprising positioning a shock
absorber between the connectors.
18. A method as claimed in claim 17, wherein the shock absorber absorbs
longitudinally directed shock generated by firing at least one perforating device.
19. A method as claimed in claim 17, wherein the detonation train extends
longitudinally through the shock absorber.
20. A method as claimed in claim 16, wherein each of the perforating device
connectors is attached to a perforating gun.
-16-
21. A method as claimed in claim 16, wherein at least one of the perforating
device connectors is attached to a perforating gun.
22. A method as claimed in claim 16, wherein at least one of the perforating
device connectors is attached to a firing head.
23. A method as claimed in claim 16, wherein an engagement device permits
relative displacement between the connectors in one longitudinal direction, but
prevents relative displacement between the connectors in an opposite
longitudinal direction.
24. A well system, comprising:
a perforating assembly including multiple perforating guns and multiple
shock absorbers, and wherein each shock absorber is interconnected between at
least two of the perforating guns.
25. A well system as claimed in claim 24, wherein each shock absorber
mitigates transmission of shock from one connector to another, the connectors
being longitudinally compressible but prevented from elongating.
26. A well system as claimed in claim 24, wherein a detonation train extends
through the shock absorbers.