Apparatus and method for inserting a pump within a conduit

Abstract

 The invention disclosed is a pump which can be inserted into a pipe string to increase the recovery of fluid from a well. The invention includes a pump secured within the pipe string by packers mounted to the upper and lower ends of the pump. The pump is actuated by pressurized hydraulic fluid to enhance the recovery of oil from the pipe string.

Description

TECHNICAL FIELD

[0001] The invention relates to increasing the flow rate of fluid in a conduit and, more particularly, to a pump assembly that is easily inserted into and secured within an oil well pipe string for increasing recovery of oil from the well.

BACKGROUND OF THE INVENTION

[0002] Oil and other petroleum products are generally found in mineral formations located beneath the surface of the earth. Recovering oil from such deposits requires that a well be drilled of often great length to gain access to the formation. Once the well is drilled, a casing of concrete or other suitable material is formed around the interior walls of the well to strengthen the well and avoid erosion or crumbling of the well walls. Oil in the formation is then recovered through a pipe string inserted into the formation through the well casing.

[0003] In most cases, oil within the formation is initially under sufficient pressure to cause the oil to flow up the pipe string to the surface without any assistance. However, as oil is depleted from the formation, pressure within the formation is often reduced to an extent that the flow rate of oil through the pipe string is concomitantly reduced to an unacceptably low level or even discontinues.

[0004] In the past, the problem of insufficient or discontinued flow of product from the formation was solved by placing a hydraulically actuated pump, such as a jet or hydraulic pump, at or near the lower end of the pipe string. However, this procedure typically involves the costly and time-consuming task of placing a workover rig above the well and removing virtually the entire length of the pipe string, piece by piece, so that a special length of pipe, known as a bottomhole assembly, having internal structure suitable for supporting a pump, can be placed at or near the bottom of the string. The pipe string is then reassembled, again, piece by piece, and lowered into the well by the workover rig. The pump is then secured to the bottomhole assembly often by wireline.

[0005] Accordingly, to avoid the cost and lost production time associated with removal and replacement of the pipe string to place a pump in a well, there is a need for a pump that can be lowered into and secured within the existing pipe string, without the need to remove the string from the well.

SUMMARY OF THE INVENTION

[0006] The present invention is an apparatus and method for inserting and securing a pump assembly within an existing pipe string, without the need for a bottomhole assembly or any auxiliary support structure for the pump within the string. The pump assembly includes a pump to which is secured a sealing assembly. The seals of the sealing assembly are adjustable from a retracted position, allowing insertion of the pump assembly into the pipe string, and an expanded position, in which the sealing assembly secures the pump within the pipe string and seals the string against the flow of fluid around the pump.

[0007] In accordance with one aspect of the invention, the sealing assembly includes a pair of packers secured to the upper and lower ends of the pump.

[0008] In accordance with another aspect of the invention, the upper packer of the pump assembly is set by wireline tool, once the pump assembly is located in a desired position within the pipe string. The lower packer is then set hydraulically to fully secure and seal the pump assembly within the pipe string.

[0009] In accordance with yet another aspect of the invention, both the upper and lower packer are set by wireline. The lower packer is first set at a desired position within the pipe string. An assembly of a sleeve secured to and extending downwardly from the upper packer is then lowered into engagement with the lower packer. The upper packer is then set by wire line tool and a pump is lowered into engagement with the sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The following Detailed Description refers to the Drawings, wherein:

FIGURE 1 illustrates a side view of a first embodiment of the invention installed within a well, wherein the pipe string and casing are shown in cross-section;

FIGURES 1A through 1C illustrate various steps of placing the first embodiment of the invention within a pipe string, wherein the pump assembly is shown in partial cross-section and the pipe string and drill casing are shown in full cross-section;

FIGURE 2 is a schematic cross-section of a reverse-flow jet pump for use in the present invention;

FIGURE 3 is a schematic cross-section of a standard-flow jet pump for use in the present invention;

FIGURE 4 is a side view of a second embodiment of the invention installed within a well, wherein the pipe string and well casing are shown in cross-section; and

FIGURES 4A through 4D illustrate various steps of placing the second embodiment of the invention within a pipe string, wherein the pump assembly is shown in partial cross-section and the pipe string and drill casing are shown in full cross-section.

DETAILED DESCRIPTION

[0011] Shown in FIGURE 1 is a pump assembly 10 installed within a pipe string 12 for increasing the recovery of oil by the pipe string 12. The pipe string 12 is surrounded by a well casing 14. The pipe string 12 extends through and is spaced from the well casing 14, forming an annular conduit between the pipe string 12 and the well casing 14.

[0012] The pump assembly 10 is preferably preassembled, for use in deviated wells. Portions of such wells deviate or vary from the vertical by as much as 60° or more. As such, the downward force imparted by components of the pump assembly 10 lowered into the pipe string 12 would likely be insufficient to easily or adequately secure adjacent components of the assembly within the pipe string. The unitary construction of pump assembly 10 eliminates the need to construct the pump assembly 10 within a deviated well.

[0013] The pump assembly 10 includes a sleeve 16 for housing an hydraulically actuated pump 18, shown in FIGURES 1C and 2. Extending from the upper end of the sleeve 16 is a tubular pup joint 20. The pup joint 20, in turn, is secured to the passageway of an upper packer 22. Similarly, secured to and extending from the lower end of the sleeve 16 is a tubular pup joint 24, which in turn is secured to the fluid passageway of a lower packer 26. Secured to and extending downwardly from the lower packer 26 is a nipple assembly 28, having a passage in communication with the pipe string 12. Secured to the lower end of the nipple assembly 28 is a wireline re-entry guide 30, which facilitates retrieval of a wireline into the nipple assembly 28 and through the pump assembly 10, as needed.

[0014] The upper packer 22 is of the type set by wireline tool, such as a "Magnum Type GT" packer, manufactured by Dresser Industries, Inc. The pump assembly 10 is initially secured at a desired location within the pipe string 12 by actuating the upper packer 22 by wireline tool. Such actuation expands the upper packer 22 from a retracted position, allowing insertion of the pump assembly 10 through the pipe string 12, into an expanded position, securing the pump assembly 10 within the pipe string 12. In the expanded position, the upper packer 22 also seals the pipe string 12 against the passage of oil and other fluid beyond the upper packer 22, around the pump assembly 10.

[0015] The lower packer 26 is of the type set hydraulically, such as a "Magnum Type PG-1" packer manufactured by Dresser Industries, Inc. The lower packer 26 is actuated from a retracted position, allowing insertion of the pump assembly 10 through the pipe string 12, into an expanded position, securing the lower end of the pump assembly 10 to the pipe string 12. In the expanded position, the lower packer 26 also seals the pipe string against the passage of oil and other fluid beyond the lower packer 26, around the pump assembly 10.

[0016] The lower packer 26 is set, or actuated, after the upper packer 22 has been set. This is accomplished by inserting a plug (not shown) in the nipple assembly 28 by wireline. Pressurized hydraulic fluid is then supplied to the lower packer 26 to set the packer. The plug is then removed from the nipple assembly 28 by wireline.

[0017] The upper and lower packers 22 and 26 are both constructed to be set permanently within the pipe string 12. In the alternative, one or both of the upper and lower packers 22 and 26 may be retrievable. However, because permanently set packers have fluid passageways of relatively larger diameter as compared with the retrievable packers, it is preferable that both the upper and lower packers 22 and 26 be of the permanently set variety.

[0018] The upper and lower packers 22 and 26 form a seal assembly which both secures the pump assembly 10 within the pipe string 12 and forms a sealed, substantially annular chamber 32 defined by the exterior of the pump assembly 10 and the interior of the pipe string 12, between the upper and lower packers 22 and 26. The pump assembly 10 is secured within the pipe string 12 adjacent perforations 34 in the pipe string 12, formed by conventional means. The perforations allow the flow of fluid between the sleeve 16 and the annular space between the pipe string 12 and well casing 14.

[0019] The sleeve 16 includes ports 38 that allow fluid communication between the pump 18, the chamber 32 and the annular space between the pipe string 12 and the well casing 14 through the perforations 34.

[0020] FIGURES 1A, 1B and 1C illustrate generally the method of installing the pump assembly 10 within the pipe string 12. As is illustrated in FIGURE 1A, the perforations 34 are first made through the pipe string 12 at a desired depth. As is illustrated in FIGURE 1B, the previously assembled pump assembly 10 (without the pump 18) is lowered by wireline into the pipe string 12 to a location where the perforations 34 and the pipe string 12 are substantially adjacent the sleeve 16 of the pump assembly 10. The upper packer 22 is then set by wireline tool. The lower packer 26 is then set hydraulically. As shown in FIGURE 1C, the pump 18 is then inserted into the pump assembly 10 by wireline and secured within the sleeve 16.

[0021] The pump 18 is preferably a reverse-flow jet pump, the operation and construction of which is shown in the schematic cross-section in FIGURE 2. The flow of pressurized hydraulic fluid used to actuate the pump 18 and the flow of pumped fluid from the pipe string 12 are indicated by bold arrows in FIGURE 2.

[0022] Referring to FIGURES 1 and 2, the pump 18 includes a nozzle 40 which ejects the pressurized hydraulic fluid upwardly into a diffuser 42. Prior to entering the diffuser 42, the pressurized hydraulic fluid mixes with and imparts momentum to oil and other fluids received from an inlet 44 at the lower end of the pump 18, which is in fluid communication with the lower packer 26 and the pipe string 16 below the pump assembly 10. A mixture of the hydraulic fluid, oil and other fluid from the pipe string 12 is discharged under pressure from the diffuser 42, through the upper packer 22, and to the surface through the pipe string 12.

[0023] Referring now to FIGURE 3, a pump 50 is shown which may used in the pump assembly 10 of FIGURE 1 as an alternative to the reverse-flow jet pump 18 shown in FIGURE 2. The flow of hydraulic fluid and pumped fluid are illustrated by bold arrows in FIGURE 3.

[0024] Referring to FIGURES 1 and 3, the pump 50 is a standard-flow jet pump. When incorporated in the pump assembly 10, pressurized hydraulic fluid is supplied to the inlet 52 of the pump 50, through the upper packer 22 and the pup joint 20. The hydraulic fluid is forced by a nozzle 54 into a downwardly extending diffuser 56. Prior to entering the diffuser 56, the hydraulic fluid mixes with oil and other fluid received from the pipe string 12 through the lower packer 26 and the pup joint 24. The pressurized mixture of hydraulic fluid, oil and other fluids received from the pipe string 12 are discharged under pressure from the pump 50, through ports 38 and then the perforations 34 in the pipe string 12. This mixture of fluids is then forced to the surface through the annular passage between the pipe string 12 and the well casing 14.

[0025] As is shown in FIGURES 2 and 3, the jet pumps 18 and 50 are preferably mounted within a sleeve 16 that is a sliding sleeve. Thus, the sleeve 16 includes a slide 60, which may be adjusted by conventional means to close the ports 38 in the sleeve 16 when operation of either of the pumps 18 or 50 is not desired.

[0026] The pup joints 20 and 24 are preferably of a length which will allow the entire pump assembly 10 to fit within a single segment of the pipe string 12, while providing sufficient length upstream and downstream of the pumps 18 and 50 to reduce turbulence in the flow of fluids prior to entering the pumps and/or prior to discharge into the pipe string 12.

[0027] FIGURE 4 illustrates a pump assembly 10' for use in non-deviated wells. Components of pump assembly 10' that are substantially identical in construction and function to the components of pump assembly 10 of FIGURE 1 are identified with the same reference numeral, followed by a prime ("'") designation. The pump assembly 10' differs from pump assembly 10 primarily in the construction and function of the lower packer 62, the means and method by which the lower packer 62 is secured to the remainder of the pump assembly 10', and the method by which the pump assembly 10' is installed within the pipe string 12.

[0028] The lower packer 62 of the pump assembly 10' is set by wireline, such as a "Magnum Type GT" packer manufactured by Dresser Industries, Inc. The lower packer 62 is secured to the lower end of the pump assembly 10' by means of a latch seal assembly 64, which is secured to the pup joint 24' by means of a collar 66. It will be appreciated that the latch seal assembly 64 can be secured to the lower packer 62 by stabbing the lower end of the assembly 64 into the upper end of the packer 62.

[0029] In use, the lower packer 62 is secured to a desired location within the pipe string 12 by wireline tool. The remainder of the pump assembly 10' is lowered by wireline into the pipe string 12 and stabbed into secure engagement with the lower packer 62 by means of the latch seal assembly 64. The upper packer 22' is then set by wireline tool to fully secure the pump assembly 10' within the pipe string 12.

[0030] FIGURES 4A, 4B and 4C illustrate the method of installing the pump assembly 10' within the pipe string 12. Referring to FIGURE 4A, perforations 34 are made in the pipe string 12 by conventional means. Referring to FIGURE 4B, the lower packer 62 is lowered into position within the pipe string 12 and set by wireline tool, at a point below the perforations 34. Referring next to FIGURE 4C, the remainder of the pump assembly 10' (without the pump 18') is lowered into the pipe string 12 and stabbed into the lower packer 62. Referring now to FIGURE 4D, a pump 18' is then lowered by wireline into the pump assembly 10' and secured within the sleeve 16'.

[0031] It will be appreciated that either of jet-pumps 36 or 56, shown in FIGURES 2 and 3, may be utilized in the construction and operation of the pump assembly 10'. In addition, it will be apparent that either of the packers 22' and 62 of the pump assembly 10' may be retrievable, if desired.

[0032] Other hydraulic pumps could be used as a substitute for the jet pumps shown in the embodiments of FIGURES 1 and 4. A bottomhole assembly can be used to secure either a jet pump or a hydraulic pump to the embodiments of FIGURES 1 and 4, in place of the sleeves 16 and 16'.

[0033] While at least two embodiments of the present invention have been described in detail herein and shown in the accompanying Drawings, it will be evident that various further modifications and substitutions of parts and elements are possible without departing from the scope and spirit of the invention.

Claims

1. A pump assembly for insertion into a conduit to increase the flow of fluid through the conduit, comprising:
   a pump means for insertion within the conduit and for pumping fluid within the conduit; and
   sealing means secured to the pump means and adjustable from a retracted position, for insertion into the conduit, to an expanded position, for securing the pump means within the conduit and sealing the conduit to prevent the flow of fluid around the pump means.

2. The pump assembly of Claim 1 wherein the sealing means comprises a plurality of seals secured at opposite ends of the pump means, the seals being expandable for securing the pump means within the conduit and for sealing the conduit against passage of fluid around the pump means.

3. The pump assembly of Claim 2 wherein the seals, the pump means and the conduit form a chamber when the pump assembly is inserted into the conduit and the seals are expanded.

4. The pump assembly of Claim 3 wherein the pump means is hydraulically actuated in response to pressurized fluid supplied to the chamber formed when the pump assembly is secured within the conduit.

5. The pump assembly of Claim 4 wherein the pump means is actuated by hydraulic fluid supplied through one of the seals, the pump means draws fluid to be pumped through the seal at the opposite end of the pump means, and the pump means discharges the pumped fluid at a location between the seals.

6. The pump assembly of Claim 1 wherein the sealing means includes at least two seals secured to the pump means on opposite ends of the pump means and wherein the pump means is actuated by pressurized fluid received through an inlet port positioned between the seals.

7. The pump assembly of Claim 1 wherein the seal means includes at least a first and a second seal secured to opposite ends of the pump means, wherein the pump means is actuated by pressurized fluid received through the first seal, and wherein the pump means draws fluid from the conduit through the second seal and discharges the pumped fluid between a first and second seal.

8. A pump assembly for insertion into a tubing string to increase the flow rate of fluid through the string, comprising:
   a hydraulically actuated pump;
   a first packer secured to the upper end of the pump;
   a second packer secured to the lower end of the pump; and
   wherein the pump is actuated to increase the flow rate of fluid through the string.

9. The pump assembly of Claim 8 wherein the upper and lower packers are both set by wire line tool.

10. The pump assembly of Claim 8 wherein the upper packer is set by wire line tool and the lower packer is set hydraulically.

11. The pump assembly of Claim 8 wherein the pump comprises a jet pump.

12. The pump assembly of Claim 8 wherein the pump comprises a hydraulic pump.

13. The pump assembly of Claim 8 wherein the upper packer is secured to the pump by tubing of sufficient length to substantially reduce the turbulence of the flow of fluid between the upper packer and the pump.

14. The pump assembly of Claim 8 wherein the lower packer is secured to the pump by tubing of sufficient length to substantially reduce the turbulence of the flow of fluid between the lower packer and the pump.

15. The pump assembly of Claim 8 wherein the upper and lower packers are both permanently set packers.

16. A method for increasing the flow of fluid in a pipe string, comprising:
   setting a first packer in sealing engagement with the string;
   setting a second packer in sealing engagement with the string;
   securing a pump between the first and second packers in fluid communication with the first and second packers; and
   actuating the pump to increase the flow rate of fluid recovered from the string.

17. The method of Claim 16 wherein the step of actuating the pump is further characterized by perforating the string adjacent the pump and supplying pressurized fluid through the perforated string to actuate the pump.

18. The method of Claim 16 wherein the step of actuating the pump is further characterized by supplying pressurized fluid through the first packer to actuate the pump.

19. The method of Claim 16 wherein the step of setting the first packer is further characterized by setting the first packer with a wireline tool.

20. The method of Claim 19 wherein the step of setting the second packer is further characterized by setting the second packer hydraulically after the first packer has been set.

21. The method of Claim 19 wherein the step of setting the second packer is further characterized by setting the second packer by wire line tool.

22. The method of Claim 16 wherein the second packer is set by wire line tool before the first packer is set, and wherein the step of securing the pump between the first and second packers if further characterized by securing to the first packer a sleeve for supporting the pump, and stabbing the sleeve and first packer into engagement with the second packer.

Drawing