U.S. patent application number 12/389799 was filed with the patent office on 2010-08-26 for hydraulic installation method and apparatus for installing a submersible pump.
This patent application is currently assigned to Smith International, Inc.. Invention is credited to Leland Traylor.
Application Number | 20100212914 12/389799 |
Document ID | / |
Family ID | 42629944 |
Filed Date | 2010-08-26 |
United States Patent
Application |
20100212914 |
Kind Code |
A1 |
Traylor; Leland |
August 26, 2010 |
Hydraulic Installation Method and Apparatus for Installing a
Submersible Pump
Abstract
Aspects of this invention include a method for deploying a small
diameter submersible pump in a deviated wellbore. The submersible
pump is first lowered into the production tubing under the
influence of gravity. The pump includes a sealing member deployed
thereabout which provides a releasable seal with an interior
surface of the production tubing. The pump is then forced deeper
into the production tubing (e.g., into a deviated section of the
wellbore). This is accomplished via introducing a column of liquid
(such as water) into the production tubing above the pump. The
liquid exerts a force on the pump and sealing member so as to force
the pump deeper into the well, thereby drawing one or more power
lines into the wellbore with the pump. The invention advantageously
enables a small diameter submersible pump to be economically
deployed in a highly deviated wellbore. The invention also
advantageously enables deployment into partially obstructed and/or
damaged tubing.
Inventors: |
Traylor; Leland; (Freedom,
WY) |
Correspondence
Address: |
Smith International, Inc.;Patent Services
1310 Rankin Rd.
HOUSTON
TX
77073
US
|
Assignee: |
Smith International, Inc.
Houston
TX
|
Family ID: |
42629944 |
Appl. No.: |
12/389799 |
Filed: |
February 20, 2009 |
Current U.S.
Class: |
166/377 ;
166/106; 166/387 |
Current CPC
Class: |
E21B 23/08 20130101;
E21B 43/128 20130101 |
Class at
Publication: |
166/377 ;
166/387; 166/106 |
International
Class: |
E21B 23/08 20060101
E21B023/08; E21B 23/00 20060101 E21B023/00; E21B 43/00 20060101
E21B043/00 |
Claims
1. A method for installing a small diameter submersible pump in
production tubing, the production tubing being deployed in a
deviated wellbore, the method comprising: (a) providing a length of
production tubing deployed in a deviated wellbore, the production
tubing including a sealing device deployed therein at a
predetermined measured depth; (b) providing a small diameter pump
having a fluid inlet and a fluid outlet, the pump further including
a sealing member deployed about an outer surface of the pump, the
sealing member deployed axially between the fluid inlet and the
fluid outlet, the pump further including at least one power line
coupled thereto; (c) lowering the pump into the production tubing,
a gravitational force drawing the pump into the tubing, the sealing
member contacting and providing a releasable seal with an inner
surface of the production tubing, the at least one power line
extending upward from the pump out an upper end of the production
tubing; and (d) forcing the pump deeper into the production tubing
by introducing a liquid into the production tubing above the pump,
the liquid providing a downward force on the sealing member and the
pump, said downward force sufficient to force the pump deeper into
the wellbore through a deviated section of the production tubing
into engagement with the sealing device.
2. The method of claim 1, further comprising: (e) exerting an
upward force on the at least one power line to: (i) disengage the
pump from the sealing device and (ii) release the releasable seal
between the sealing member and the production tubing; and (f)
removing the pump from the production tubing via pulling upwards on
the at least one power line.
3. The method of claim 1, wherein the deviated section of the
production tubing includes a substantially horizontal section.
4. The method of claim 1, wherein the sealing device comprises a
sealing nipple deployed at a lower end of the production
tubing.
5. The method of claim 1, wherein: the production tubing further
includes a stripper deployed at an upper end thereof, the at least
one power line being sealingly engaged with the stripper; and the
at least one power line being drawn into the production tubing
through the stripper in both (c) and (d).
6. The method of claim 1, wherein the liquid is water.
7. The method of claim 1, wherein the liquid is pressurized.
8. The method of claim 1, wherein the sealing member comprises a
sand seal.
9. The method of claim 1, wherein the pump is lowered in (c) until
the gravitational force is unable to draw it deeper into the
wellbore.
10. A method for installing a small diameter submersible pump in
production tubing, the production tubing being deployed in a
deviated wellbore, the method comprising: (a) lowering a small
diameter submersible pump into a length of production tubing, the
production tubing deployed in a deviated wellbore, a gravitational
force drawing the pump into the production tubing, the pump
including a sealing member deployed about an outer surface thereof,
the sealing member deployed axially between a fluid inlet and a
fluid outlet, the pump further including at least one power line
coupled thereto and extending upward to a surface location; and (b)
forcing the pump deeper into the production tubing by introducing a
liquid into the production tubing above the pump, the liquid
providing a downward force on the sealing member and the pump, said
downward force sufficient to force the pump deeper into the
wellbore and into engagement with a seating nipple deployed in the
production tubing.
11. The method of claim 10, further comprising: (c) exerting an
upward force on the at least one power line to: (i) disengage the
pump from the seating nipple and (ii) release the releasable seal
between the sealing member and the production tubing; and (d)
removing the pump from the production tubing via pulling upwards on
the at least one power line.
12. The method of claim 10, wherein: the production tubing further
includes a stripper deployed at an upper end thereof, the at least
one power line being sealingly engaged with the stripper; and the
at least one power line being drawn into the production tubing
through the stripper in both (a) and (b).
13. The method of claim 10, wherein the liquid is water.
14. The method of claim 10, wherein the liquid is pressurized.
15. The method of claim 10, wherein the sealing member comprises a
sand seal.
16. The method of claim 10, wherein the pump is lowered in (a)
until the gravitational force is unable to draw it deeper into the
wellbore.
17. A submersible pumping system comprising: a submersible pump
deployed in a length of production tubing, the production tubing
deployed in a deviated subterranean wellbore; the submersible pump
comprising a pump body having a fluid inlet and a fluid outlet, a
releasable sealing member deployed about an outer surface of the
pump body axially between the fluid inlet and the fluid outlet, the
sealing member contacting and forming a releasable seal with an
inner surface of the production tubing, the pump further including
at least one power line connected thereto, the power line extending
upwards through the production tubing to a surface location.
18. The submersible pumping system of claim 17, wherein the sealing
member comprises a sand seal.
19. The submersible pumping system of claim 17, wherein the at
least one power line passed through a stripper deployed on an upper
end of the production tubing.
20. The submersible pumping system of claim 17, wherein the
production tubing is deployed in deviated wellbore having a
substantially horizontal section.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to downhole
submersible pumping systems. More particularly, the invention
relates to a method and apparatus for hydraulically installing a
submersible pump used in artificial lift applications in
hydrocarbon producing wells.
BACKGROUND OF THE INVENTION
[0002] Hydrocarbons, and other fluids, are often contained within
subterranean formations at elevated pressures. Wells drilled into
these formations allow the elevated pressure within the formation
to force the fluids to the surface. However, in low pressure
formations, or when the formation pressure has diminished, the
formation pressure may be insufficient to force the fluids to the
surface. In these cases, a pump may be installed to provide the
required pressure to produce the fluids.
[0003] The volume of well fluids produced from a low pressure well
is often limited, thus limiting the potential income generated by
the well. For wells that require pumping systems, the installation
and operating costs of these systems often determine whether a
pumping system is installed to enable production or the well is
abandoned. Among the more significant costs associated with pumping
systems are the costs for installing, maintaining, and powering the
system. Reducing these costs may allow more wells to be produced
economically and increase the efficiency of wells already having
pumping systems.
[0004] In recent years, the deployment of small diameter pumps in
the production tubing has often provided for economic recovery of
well bore fluids. One example of such a small diameter pump is
disclosed in commonly invented and commonly assigned U.S. Pat. No.
7,252,148. Commercially available small diameter pumps are commonly
powered via hydraulic actuation and are therefore connected to the
surface via one or more hydraulic lines. Flexible hydraulic tubing
is often preferred due to its low cost. Those of skill in the art
will appreciate that electrical and mechanical actuation of
downhole pumping systems is also known.
[0005] In service, the production tubing is typically first
deployed in a cased wellbore. The small diameter pump is then
typically lowered into the well under of the influence of the
Earth's gravitational field. The hydraulic (or electric) power
lines are dragged behind until the pump reaches the bottom of the
well and is seated in an appropriate connector (e.g., a nipple
deployed at the bottom or somewhere along the length of the
production tubing).
[0006] Deviated wells are commonly utilized to improve production.
Wellbores including vertical, doglegged, and horizontal sections
are now common. In such deviated wellbores, deployment of a small
diameter pump into the production tubing can be problematic.
Gravitational force alone is usually not sufficient to drag the
pump around the dogleg or along the horizontal section of the well.
To overcome this problem, the pump may be rigidly mounted in the
production tubing and forced downhole with the production tubing.
However, this results in a "permanent" deployment of the pump and
necessitates the removal of the production tubing should the pump
fail or merely require routine service. As will be appreciated by
those of ordinary skill in the art, such removal of the production
tubing is time consuming and therefore expensive. The use of rigid
hydraulic lines (or rigid power lines) by which the pump may be
forced down the well has also been contemplated. However, rigid
hydraulic lines are prone to buckling under compression and are
therefore not typically suitable for forcing a pump through a
highly deviated section of a wellbore (or through a section having
a high dogleg severity). Moreover, this approach adds significant
cost to the operation (due to the increased cost of the rigid power
lines).
[0007] Therefore, a need remains for a method for deploying a small
diameter pump in a deviated borehole and a small diameter pump or
small diameter pumping system suitable for such deployment.
SUMMARY OF THE INVENTION
[0008] The present invention addresses one or more of the
above-described drawbacks of the prior art. One aspect of the
invention includes a method for deploying a small diameter
submersible pump in a deviated wellbore. Methods in accordance with
the present invention include at least a two-stage deployment of
the pump in the deviated wellbore. In a first stage, the
submersible pump is lowered into the production tubing under the
influence of gravity. During this first stage the pump is typically
supported by at least one power line (e.g., a hydraulic line) that
extends from the pump to the surface. The pump includes a sealing
member deployed thereabout which provides a releasable seal with an
interior surface of the production tubing. In a second stage, the
pump is forced deeper into the production tubing (e.g., into a
highly deviated section of the wellbore). This is accomplished via
introducing a column of liquid (such as water) into the production
tubing above the pump. The liquid exerts the necessary force on the
pump and sealing member so as to force the pump deeper into the
well. The pump preferably includes at least one power line that
extends to the surface and is drawn into the wellbore during the
first and second stages of the deployment.
[0009] Exemplary embodiments of the present invention
advantageously provide several technical advantages. For example,
the present invention enables a small diameter submersible pump to
be economically deployed in a highly deviated wellbore (e.g., a
wellbore including an extended reach horizontal section). The
invention also allows the deployment of pumps into tubing that is
partially obstructed by solids such as paraffin or scale, and
allows pumps to pass by tight spots caused by mechanical tubing
damage. Moreover, the invention does not require the use of rigid
power lines. Nor is it necessary to mount the pump in the
production tubing prior to deployment. The invention also
advantageously enables simple and economic removal of the pump from
the wellbore.
[0010] In one aspect the present invention includes a method for
installing a small diameter submersible pump in production tubing.
The method includes providing a length of production tubing
deployed in a deviated wellbore, the production tubing including a
sealing device deployed therein at a predetermined measured depth.
The method further includes providing a small diameter pump having
a fluid inlet and a fluid outlet. The pump further includes a
sealing member deployed about an outer surface of the pump, the
sealing member deployed axially between the fluid inlet and the
fluid outlet. At least one power line is coupled to the pump. The
pump is lowered into the production tubing with gravitational force
drawing the pump into the tubing. The sealing member contacts and
provides a releasable seal with an inner surface of the production
tubing. The power line extends upward from the pump out an upper
end of the production tubing. The method still further includes
forcing the pump deeper into the production tubing by introducing a
liquid into the production tubing above the pump. The liquid
provides a downward force on the sealing member and the pump, the
downward force being sufficient to force the pump deeper into the
wellbore through a deviated section of the production tubing and
into engagement with the sealing device.
[0011] In another aspect, this invention includes a method for
installing a small diameter submersible pump in production tubing,
the production tubing being deployed in a deviated wellbore. The
method includes lowering a small diameter submersible pump into the
production tubing, gravitational force drawing the pump into the
production tubing. The pump includes a sealing member deployed
about an outer surface thereof, the sealing member being deployed
axially between a fluid inlet and a fluid outlet. At least one
power line is coupled to the pump and extends upward to a surface
location. The method further includes forcing the pump deeper into
the production tubing by introducing a liquid into the production
tubing above the pump. The weight (and/or pressure) of the liquid
provides a downward force on the sealing member and the pump, the
downward force being sufficient to force the pump deeper into the
wellbore and into engagement with a seating nipple deployed in the
production tubing.
[0012] In still another aspect, the invention includes a
submersible pumping system. The pumping system includes a
submersible pump deployed in a length of production tubing, the
production tubing deployed in a deviated subterranean wellbore. The
submersible pump includes a pump body having a fluid inlet and a
fluid outlet. A releasable sealing member is deployed about an
outer surface of the pump body axially between the fluid inlet and
the fluid outlet. The sealing member contacts and forms a
releasable seal with an inner surface of the production tubing. The
pump further includes at least one power line connected thereto,
the power line extending upwards through the production tubing to a
surface location.
[0013] The foregoing has outlined rather broadly the features and
technical advantages of the present invention in order that the
detailed description of the invention that follows may be better
understood. Additional features and advantages of the invention
will be described hereinafter which form the subject of the claims
of the invention. It should be appreciated by those skilled in the
art that the conception and the specific embodiment disclosed may
be readily utilized as a basis for modifying or designing other
structures for carrying out the same purposes of the present
invention. It should also be realized by those skilled in the art
that such equivalent constructions do not depart from the spirit
and scope of the invention as set forth in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] For a more complete understanding of the present invention,
and the advantages thereof, reference is now made to the following
descriptions taken in conjunction with the accompanying drawings,
in which:
[0015] FIG. 1 depicts a prior art arrangement in which a
submersible pump is deployed in production tubing in a vertical
wellbore.
[0016] FIG. 2 depicts one exemplary embodiment of the present
invention in flow chart form.
[0017] FIG. 3 depicts a semisubmersible pump partially deployed in
a deviated wellbore.
[0018] FIG. 4 depicts the semisubmersible pump depicted on FIG. 3
fully deployed in the deviated wellbore.
DETAILED DESCRIPTION
[0019] With reference now to FIG. 1, a prior art pumping system 100
includes a small diameter submersible pump 120 operatively
connected with surface equipment 150. The pump 120 is deployed in
production tubing 140 in a cased wellbore 32. The production tubing
140 forms a flowbore that extends upward to surface equipment 150
and carries wellbore fluid from the submersible pump 120 to the
surface. Submersible pump 120 is connected to surface equipment 150
via power lines 122. The surface equipment 150 may include various
pumping equipment, valves, piping, power sources, and the like, for
example, including a gas-over-liquid scheme to develop the
necessary hydraulic pressure needed to drive the submersible pump
120.
[0020] As is known to those of ordinary skill in the art, the
operation of the submersible pump 120 draws wellbore fluid from the
wellbore 32 into the pump 120 via a fluid inlet 124. The fluid is
pressurized by the pump 120 and pumped out through fluid outlet 126
to the surface as depicted at 130. As depicted, pump 120 is engaged
with a sealing device 142 (e.g., a seating nipple) deployed at the
bottom of the production tubing 140. Such engagement enables
wellbore fluids in the wellbore to enter the pump via inlet
124.
[0021] In operation, submersible pump 120 may be lowered into the
production tubing 140 under the influence of gravity. During this
operation, the pump is typically supported by the power lines 122
(e.g., by hydraulic or electrical power lines). The weight of the
pump provides the necessary force for the above-described
engagement with the sealing device 142. This practice is well
established in vertical (or near vertical) wells. However, in
deviated wellbores such gravity assisted deployment can be
problematic as the gravitational force is not sufficient to move
the pump through the deviated section of the wellbore. Deployment
of submersible pumps is particularly problematic in wellbores
having horizontal or near horizontal sections (e.g., having an
inclination greater than about 75 degrees).
[0022] With reference now to FIGS. 2 through 4, one exemplary
method embodiment 200 in accordance with the present invention is
described in more detail. In FIG. 2, the invention is depicted in
flowchart form. An exemplary submersible pump 320 in accordance
with the present invention is depicted in a deviated wellbore 42
both before (FIG. 3) and after (FIG. 4) step 208 in method 200.
[0023] At 202, a length of production tubing 140 is provided in a
deviated wellbore 42. The production tubing 140 includes a sealing
device 142 (e.g., a seating nipple) deployed at a predetermined
depth in the well (e.g., at the lower end of the tubing as depicted
in FIGS. 3 and 4). The production tubing may optionally further
include a stripper 148 deployed at the surface for sealingly
engaging power line(s) extending upward from a pump. The production
tubing typically also includes one or more ports 144 located at the
surface.
[0024] A small diameter submersible pump 320 is provided at 204.
The pump 320 includes a fluid inlet 324 and a fluid outlet 326. The
fluid inlet 324 is typically on a lower end of the pump 320 and the
fluid outlet 326 on an upper end of the pump 320, although the
invention is not limited in this regard. The pump 320 further
includes a sealing member 328 deployed about an outer surface 329
of the pump, the sealing member 328 being located axially between
the fluid inlet 324 and outlet 326. In a preferred embodiment of
the invention, the sealing member includes a conventional sand
seal, for example, a Flexite.RTM. ring available from
Harbison-Fisher Mfg. Co., Fort Worth, Tex. At least one power line
322, e.g., one or more hydraulic lines, is further coupled to an
upper end of the pump 320.
[0025] At 206, the semisubmersible pump 320 is lowered into the
deviated wellbore 42 under the influence of gravity (i.e., gravity
draws the pump 320 down into the well). As shown on FIG. 3, sealing
member 328 contacts an inner surface 145 of the production tubing
140 forming a releasable seal (which may also be referred to as a
partial seal) therewith. As the pump 320 is lowered into the well
42, the power line(s) 322 (e.g., the hydraulic lines) are typically
used to support the pump 320 and are drawn down into the well with
the pump 320. In a preferred embodiment of the invention (and as
depicted on FIG. 3), the power line(s) 322 may be pulled through a
conventional stripper 148, which is deployed atop the production
tubing 140 and which sealingly engages the power line(s) 322. The
pump 320 is typically lowered at step 206 until it can't be lowered
any further by gravitational force alone. As depicted on FIG. 3,
the pump is often lowered until it reaches a deviated section of
the well (e.g., having an inclination greater than about 45
degrees) or a section of the well having a high dogleg
severity.
[0026] At 208, a liquid (preferably water or an aqueous based
liquid) is introduced into the production tubing 140 via a port 144
at the surface. The weight of the liquid in the tubing 140 provides
a downward force (depicted at 360 on FIG. 4) on the sealing member
328 and on an upper surface of the pump 320 which forces the pump
320 deeper into the well, e.g., through the deviated section of the
wellbore 42 and into engagement with the sealing device 142 in the
production tubing 140 as depicted on FIG. 4. In certain embodiments
it may be advantageous to pressurize the liquid so as to increase
the downward force 360 on the pump 320. Such pressurization is
sometimes necessary in wellbores 42 having a high dogleg severity
section and/or an extended reach horizontal section. Pressurization
may also be advantageous when forcing the pump 320 through a
mechanically damaged section of the tubing 140. Notwithstanding,
the invention is not limited in these regards as the weight of the
liquid alone is often sufficient to force the pump 320 into
engagement with the seating nipple 142.
[0027] As is known to those of ordinary skill in the art,
submersible pumps can fail unexpectedly or can simply wear out over
time depending on the particular submersible pump and the
conditions in the well. This requires removal of the pump from the
well since the well ceases to produce once the submersible pump
fails. Other reasons for removing the pump from the well are also
know (e.g., including a failed installation). Thus, with continued
reference to FIG. 2, methods in accordance with the invention may
optionally further include removing the pump 320 from the wellbore
42. This may be accomplished, for example, via exerting an upward
force on the power line(s) 322 at 210 to disengage the pump 320
from the sealing device 142 (e.g., the seating nipple) and to
release (break) the releasable seal between the sealing member 328
and the production tubing 140. The pump 320 may then be pulled out
of the production tubing 140 (and out the well 42) by the power
line(s) 322 at 212.
[0028] As described above, the submersible pump 320 is equipped
with a sealing member 328 deployed about an outer surface 329 of
the pump 320. Upon deployment of the pump 320 in the wellbore 42,
the sealing member 328 sealingly engages an inner surface 145 of
the production tubing 140 (as depicted on FIGS. 3 and 4). In
preferred embodiments of the invention, the sealing member 328
forms a releasable seal with the production tubing when deployed
therein. By releasable it is meant that the seal between the pump
320 and the production tubing 140 is of moderate strength. On the
one hand, the seal must be sufficiently strong so as to support the
pressure exerted by the column of liquid in the production tubing
at step 208. On the other hand, it is important that the seal not
be so strong as to significantly resist the movement of the pump
320 down into the wellbore (either under the influence of gravity
at step 206 or under the influence of the downward force 360
provided at step 208). Moreover, it is also important that the seal
not be so strong so as to prevent the removal of the pump 320 from
the wellbore as described above at steps 210 and 212 (FIG. 2). A
seal that is too strong, may render it impossible (or overly
difficult) to remove the pump 320 via pulling upward on the power
line(s) 322 or may cause the power lines 322 to be damaged during
removal of the pump 320. This can result in the need for expensive
fishing operations or in extreme cases, the need to remove the
production tubing 140 from the wellbore 42 (if the pump 320 is
stuck) or replacement of the power lines 322 ( if they are
damaged). It has been found that a hard, self-lubricating, plastic
ring (such as a Flexite.RTM. ring sand seal available from
Harbison-Fischer) provides a seal having a suitable strength for
use in embodiments of the present invention. The ring
advantageously expands against the production tubing to form the
seal between the pump and the tubing. Moreover the ring tends not
to swell in service, which advantageously enables the pump to be
pulled out of the wellbore.
[0029] In a preferred embodiment of the invention, the pump 320
includes a hydraulically driven diaphragm pump and includes first
and second flexible hydraulic lines connected thereto. Preferred
embodiments of the pump may employ substantially any known
hydraulic actuation mechanism, and may therefore include, for
example, one or more pressure intensifiers such as disclosed in
commonly invented and commonly assigned U.S. Pat. No. 7,252,148.
Furthermore, the pump 320 preferably has a sufficiently small
diameter (e.g., less than or equal to 2.5 inch) so as to be
deployable in conventional 27/8 inch production tubing.
[0030] Although the present invention and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alternations can be made herein without departing
from the spirit and scope of the invention as defined by the
appended claims.
* * * * *