HYDRAULICALLY POWERED DOWNHOLE PISTON PUMP
A wellbore pump includes a receptacle for a pump formed into a wellbore production tubing. A pump includes a seal engageable with an interior surface of the receptacle. The seal has a pump rod passing sealingly through the seal. The pump rod has a piston in sealing engagement with an interior of the tubing on each side of the seal. A power fluid line is in hydraulic connection to an interior of the production tubing above and below the seal. A well fluid inlet port is disposed between one of the pistons. A longitudinally spaced apart check valve is disposed in the wellbore production tubing above an upper one of the pistons.
Continuation of International (PCT) Application No. PCT/IB2017/052342 filed on Apr. 24, 2018. Priority is claimed from U.S. Provisional Application No. 62/328,811 filed Apr. 28, 2018. Both the foregoing applications are incorporated herein by reference in their entirety.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENTNot Applicable
NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENTNot Applicable.
BACKGROUNDThis disclosure relates to the field of pumping systems for deep oil-, gas and water transporting wellbores. More specifically, the present disclosure relates to describes a single-acting as well as a double-acting pump system where the main parts of the pump are replaceable without a need for retrieving tubulars in the wellbore to change out pump components.
A number of different types of pumps are known to be used in deep wellbores, for example sucker rod-driven pumps and electric submersible pumps. However, there is a need for a lower complexity pump that can be installed and retrieved by light well intervention, such as for example wireline, coiled tubing or self-positioning. See, for example, International Patent Application Publication No. WO/2012/170112.
There is also a need for wellbore pumps that do not utilize sucker rods reciprocated in the wellbore from the surface to the pump, particularly in highly inclined or deviated wellbores. In such wellbores, wear and tear on the sucker rods or production tubing may result in the need for frequent repairs.
Horizontal wellbores have become very common, and to achieve better fluid production rates and total fluid recovery, pumps are known to be placed into the horizontal section of such wellbores. Pumps using sucker rods are challenging in such conditions, mainly due to wear and tear as described above, but also due to differential pressure induced sticking between the sucker rods and the production tubing. A pump which does not use sucker rods to drive the pump clearly would have a number of advantages for such wellbore applications.
The present disclosure relates to a well pump where a production tubing forms the pump housing, while an inner pump system comprising, for example, pistons, check valves, etc., may be installed and retrieved by light well intervention. Such a well pump may provide significant cost savings in pump maintenance and repair. Such a pump may provide ready access to the wellbore below the pump for interventions such as well logging, among other intervention operations. This may be of particular interest for areas where heavy weight interventions, such as using a workover rig or the like to pull out and rerun the production tubing are very costly. Offshore small size production platforms, for example, may be one application where workover rig cost is important. Also, limited crane capacity, no cost efficient derrick available, etc., play a significant role in raising the cost. It should be noted that the pump described in this disclosure also can be deployed in a wellbore wherein the pump has an external housing, for example connected to the lower end of a tubular hung into the wellbore, where the tubular needs to be retrieved to surface to retrieve the pump.
Also, this disclosure describes variations of a hydraulic operated downhole pump, using one or two control lines from surface, as well as being single-acting and dual-acting.
The present disclosure also describes how trapped gas in a production fluid filled pump chamber can be released, to avoid or minimize risk of gas locking. In addition, the present disclosure describes how wellbore fluids can be kept and discharged from an area below a dynamic seal, to minimize exposure of seals and sealing area to abrasive particles, sand and debris.
The wellbore 101 may comprise a casing or liner 100 to hydraulically isolate formations outside the casing or liner 100, and to maintain mechanical integrity of the wellbore 101. In the present example embodiment a liner 100 extends from the bottom of the wellbore 101 to above the bottom of a surface casing 104. Perforations 102 may be made in the liner 100 within a formation that produces hydrocarbons such as natural gas. The wellbore tubing 110 may extend to the surface of the wellbore 101. The wellbore tubing 110 may comprise segments (“joints”) shown at 110A and 110B each having a polished interior surface for receiving the pump components (
A hydraulic control line 116 may be mounted on the exterior of the wellbore tubing 110 and may extend from a source of pressurized hydraulic fluid (not shown) at the surface to each of two power fluid inflow ports 114. The power fluid inflow ports 114 are used to route hydraulic fluid under pressure to the pump components described with reference to
The polished joints 110A, 110B may comprise well fluid inflow ports 112 at a convenient location at the connection between the upper 110A and lower 110B polished joints. As shown in
It should be understood that the gas inflow ports 106 could be located higher up in the wellbore tubing than as illustrated in
The filter 118 may be installed and retrieved by, for example wireline, when the well has been configured with wellbore equipment as illustrated in
A lower dynamic piston 308 with associated external seals 308A may be disposed on the shaft 301 at or proximate the bottom end of the shaft 301. Referring back to
First referring to
Another example embodiment of a pump which is dual acting is shown in
The fluid discharge line 108 in
When motion of the piston and shaft assembly is reversed, the second volume 820 expands, thereby drawing wellbore fluid into the second volume 820 through the well fluid inflow port 809 from the well fluid inflow line 809A. Correspondingly, the first volume 822 decreases, thereby causing check valves 821 in the well fluid inflow ports 112 to close. The fluid is thus constrained to be moved into the discharge line 108 through the lower well fluid inflow port 808B. The check valve 816 prevents backflow of discharged well fluid through the upper well fluid inlet port 808A, thus the discharged wellbore fluid is constrained to move upwardly through the discharge line. Gas produced from the formation may enter the wellbore through gas production ports 106, substantially as explained with reference to
Another example embodiment of a well pump is shown in
As the piston and shaft assembly 900 is moved downwardly, a first volume 922 disposed between the lower dynamic piston 908 and a dual check valve sub 909 contracts. Fluid in the first volume 922 is constrained by the dual check valve sub 909 to move into the well fluid discharge line 108. In the present example embodiment, the well fluid discharge line 108 extends to a discharge fluid port 908A in the tubing 110 above the position of the check valve 905. When the piston and shaft assembly 900 moves upwardly, the first volume 922 expands, thus drawing wellbore fluid into the first volume through the dual check valve sub 909. Accordingly, the example embodiment of the wellbore pump shown in
The wellbore pump 1300 may be attached to the lower end of the wellbore tubing 1302 by an adapter or crossover sub 1304. The crossover sub 1304 may be connected to one end of a pump housing 1300A. The other end of the pump housing 1300A may be coupled to one end of a pump power chamber 1305. The pump power chamber 1305 may comprise a power chamber cylinder 1305A coupled to a lower end of the pump housing 1300A by an upper power chamber adapter 1324A. A lower end of the power chamber cylinder 1305A may be coupled to a tubing extension 1302A by a lower power chamber adapter 1324B. The tubing extension 1302A may comprise fluid inflow ports 1307 disposed at an axial position above the lower end of a fluid intake tube 1306A.
The pump power chamber 1305 may comprise a power piston 1310 that sealingly engages an interior wall of the pump power chamber cylinder 1305A. Hydraulic fluid under pressure may be provided alternatingly to each of a lower hydraulic control line 1318A coupled to the pump power chamber cylinder 1305A to a position below the power piston 1310. In the present example embodiment, hydraulic fluid pumped through the lower hydraulic control line 1318A may enter the pump power chamber cylinder 1305A through a lower power fluid inlet 1318B coupled to suitable passageways formed in the lower power chamber adapter 1324B. Correspondingly, an upper hydraulic control line 1316A may provide pressurized hydraulic fluid to a position above the power piston 1310, for example, through an upper power fluid inlet 1316B with suitable fluid passageways formed unto the upper power chamber adapter 1324A.
The fluid intake tube 1306A may sealingly pass through the power piston 1310 and be attached to the power piston such that movement of the power piston 1310 as a result or pressurizing each of the hydraulic control lines 1316A, 1318A will cause the fluid intake tube 1306A to move correspondingly.
The fluid intake tube 1306A may be attached to a pump piston 1308 disposed in the pump housing 1300A. The pump piston 1308 may divide the interior of the pump housing 1300A into an upper pump chamber 1301A and a lower pump chamber 1301B.
When hydraulic fluid 1317 is supplied to the upper hydraulic control line 1316A, causing the power piston 1310 to move downwardly, the intake tube 1306A and the pump piston 1308 move correspondingly, thereby decreasing the volume of the lower pump chamber 1301B. The pump piston 1310 may comprise internal fluid passages 1308C and check valves 1308A, 1308B, 1308D arranged such that downward motion of the pump piston 1310 will cause fluid in the lower pump chamber 1301B to move into the passages 1308C in the pump piston 1310 and to be discharged through an upper discharge tube 1306. The upper discharge tube 1306 may extend longitudinally through the crossover sub 1304 and be sealingly engaged with the crossover sub 1304. Fluid 1301 discharged through the upper discharge tube 1306 may be constrained to move upwardly through the wellbore tubing 1302 by the action of a check valve 1304A in the crossover sub 1304.
Conversely, when the power piston 1310 is caused to move upwardly by application of hydraulic power fluid 1317 to the lower power fluid inlet 1318B, the fluid intake tube 1306A, power piston 1310, pump piston 1308 and upper discharge tube 1306 move correspondingly. Thus, the upper pump chamber 1301A volume decreases. One of the check valves 1308A in the pump piston 1308 constrains the fluid in the upper pump chamber 1301A from entering the upper discharge tube 1306. At the same time, the fluid in the upper pump chamber 1301A may move through the check valve 1304A in the crossover sub 1304 and thus move into the wellbore tubing 1302. As the lower pump chamber 1301B expands correspondingly, other check valves 1308D, 1308B in the pump piston 1310 enable wellbore fluid to be drawn into the lower pump chamber 1301B through the fluid intake tube 1306A.
By positioning well fluid inlet ports 1307 in the tubing extension 1302A above the position of the fluid intake tube 1306A, a solids trap 1320 may be formed. Solids may tend to settle by gravity and thus may be largely excluded from entering the fluid intake tube 1306A. A guide nose 1322 may be used on the end of the tubing extension 1302A in some embodiments.
Another embodiment of a hydraulically operated pump is shown in
Each of the upper pump piston 1502 and the lower pump piston 1504 may comprise wiper seals, 1502A and 1504B, respectively. Longitudinal ends of the pump body 1510 and the corresponding pump pistons 1502, 1504 may define an upper pump chamber 1510A and a lower pump chamber 1510B. A fluid intake for the lower pump chamber 1510B may be provided through a check valve 1520 which will admit fluid to the lower pump chamber 1510B when it is expanded. The check valve 1520 may cause fluid to be constrained to move through a discharge line 1518, through a check ball 1514 and into the wellbore tubing 110. Correspondingly, the upper pump chamber 1510A may have a fluid intake line 1522 and a discharge through a port 1512 having a check ball 1512A therein. Enlargement and reduction of the volume of the upper pump chamber 1510A by corresponding motion of the upper piston 1502 will cause fluid to be drawn into the upper pump chamber 1510A and discharged therefrom, respectively.
Referring first to
A power chamber may be defined within the pump housing 1706 longitudinally between the connection of the pump housing 1706 to the upper adapter 1704, and a power fluid inlet port 1717 through the wall of the pump housing 1706. A part of the pump housing 1706 corresponding to the power chamber may have an enlarged internal diameter section 1706A corresponding to the length of the power chamber. A piston 1710 may be disposed within the pump housing 1706. An upper end of the piston 1710 may be in fluid communication with hydraulic power fluid that is moved under pressure into the pump housing 1706 above the top of the piston 1710 through a power fluid passage 1704C in the upper adapter. A first hydraulic control line 1716A is coupled to the power fluid passage 1704C to enable moving the piston 1710 downwardly in the pump housing 1706 by applying power fluid, e.g., hydraulic fluid under pressure to the power fluid passage 1704C. The bottom end of the piston 1710 may comprise a wiper 1720 or similar fluid seal. A pump chamber 1708 may be defined between the bottom end of the piston 1710 within the pump housing 1706 and a lower adapter 1720 coupled to the lower end of the pump housing 1706.
The lower adapter 1720 may include an intake check valve 1720A and a discharge check valve 1720B. As indicated by the arrow in the pump chamber 1720, when the piston 1710 is moved downwardly, the pump chamber decreases in volume and fluid flow opens the discharge check valve 1720B wherein discharged fluid enters the fluid discharge line 1712 and eventually into the wellbore tubing 110 through the upper adapter 1704 as explained above. The intake check valve 1720A closes during downward movement of the piston 1710. When hydraulic fluid under pressure is moved through a second hydraulic control line 1716B to the lower power fluid inlet port 1717, the piston 1710 is moved upwardly by such hydraulic fluid pressure. As the piston 1710 is moved upwardly, the intake check valve 1720A opens and the discharge check valve 1720B closes, enabling wellbore fluid to be drawn into the pump chamber 1720 by increasing the volume of the pump chamber 1720.
The piston 1710 has a bore 1710B through it from its upper end to a position on the exterior surface of the piston below dynamic seals 1710C on the piston 1710. The bore comprises a relief valve 1710A in the bore 1710B proximate the top of the piston 1710. In the case of gas being trapped within the power chamber, hydraulic power fluid pressure on second control line 1716B (used to move the piston 1710 upward in the pump housing 1706) is increased to a pressure higher than ordinary operating pressure after the piston 1710 reaches the upper end of the pump housing 1706. This increased pressure lifts the relief valve 1710 followed by opening a corresponding relief valve 1704A in the upper adapter 1704, causing any trapped gas to exit from the power chamber, through the piston 1710 and the relief valves 1710A, 1704A, and then into the tubular, e.g., the tubing 110 above the upper adapter 1704.
In some embodiments, a guide nose 1720C may be coupled to the bottom of the lower adapter 1720.
Additional features of a well fluid pump as explained above with reference to
Referring first to
Two different arrangements may be used in some embodiments. One embodiment may use a conventional metal plunger with only a metal to metal clearance. Some embodiments may use elastomeric seals or the like, located axially at each side of the discharge port, externally to the pump piston 1708.
Hydraulic fluid pressure feed to the clearance (1708B in
Referring to
The recirculation line is shown at 1756 in
Referring to
The foregoing function can be implemented with the pump piston pushing wellbore fluids down as illustrated in
Also illustrated is a function where pump power fluid can be used to flush clean the wellbore fluid chamber, by pressurizing the first control line (1716A in
Although only a few examples have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the examples. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.
Claims
1. A wellbore pump, comprising:
- a receptacle for a pump formed as part of a wellbore production tubing;
- a pump comprising a seal engageable with an interior surface of the receptacle, the seal having a pump rod passing sealingly through the seal, the pump rod having a piston in sealing engagement with an interior of the tubing on each side of the seal, the seal and the piston directly in sealing engagement with an interior surface of the receptacle;
- a power fluid line having hydraulic connection to an interior of the production tubing above and below the seal;
- a well fluid inlet port disposed between one of the pistons and the seal; and
- a longitudinally spaced apart check valve disposed in the wellbore production tubing above the piston disposed above the seal.
2. The wellbore pump of claim 1 wherein the check valve is disposed in a piston connected to the pump rod.
3. The wellbore pump of claim 1 further comprising a fluid inlet check valve in sealing engagement with the well fluid inlet port.
4. The wellbore pump of claim 1 further comprising a filter covering the well fluid inlet port.
5. The wellbore pump of claim 1 further comprising a well fluid discharge line in fluid communication with the interior of the production tubing above the longitudinally spaced apart check valve.
6. The wellbore pump of claim 5 further comprising an additional check valve disposed in the production tubing above the well fluid discharge line.
7. The wellbore pump of claim 6 further comprising well gas inlet ports in the production tubing at a position above the additional check valve.
8. The wellbore pump of claim 6 wherein the additional check valve is operable in two fluid flow directions.
9. The wellbore pump of claim 1 further comprising well gas inlet ports in the production tubing above the longitudinally spaced apart check valve.
10. The wellbore pump of claim 1 further comprising an lower inlet check valve assembly coupled to a bottom end of the production tubing below the pump and arranged such that fluid is drawn into the bottom of the tubing by the pump and is discharged to an additional fluid discharge line in fluid communication with the interior of the tubing above the bottom end of the production tubing.
11. The wellbore pump of claim 1 wherein the pump is insertable into and retrievable from the receptacle using at least one of wireline, coiled tubing and a semi-still spoolable rodconveyance.
12. A wellbore pump, comprising:
- a pump piston disposed in a pump power chamber arranged to be coupled to a wellbore production tubing or wellbore casing, the pump piston comprising check valves and flow passages therein enabling well fluid to be drawn into a pump chamber below the pump piston and a lower pump chamber adapter connecting the power chamber to the production tubing or the wellbore casing, the check valves and flow passages arranged to discharge well fluid into the production tubing above an upper pump chamber adapter connecting the wellbore tubing to the pump chamber, the upper and lower adapters comprising check valves and/or fluid flow passages to alternatingly discharge fluid from the pump chamber into each of the production tubing or wellbore casing and a well fluid return line.
13. A wellbore pump, comprising:
- a pump power piston and pump piston assembly disposed in a pump body connected to a wellbore production tubing, the pump body comprising an upper cylinder and a lower cylinder disposed on opposed longitudinal sides of a center passage through which a piston may move;
- a first control line communication with the upper cylinder between fluid seals and a bottom of the upper piston;
- a second hydraulic control line in communication with the lower cylinder;
- wiper seals on an exterior of each of the upper piston and the lower piston;. Longitudinal ends of the pump body corresponding pump pistons each may defining a respective upper pump chamber and a lower pump chamber;
- check valves configured to admit well fluid to the lower pump chamber when it is expanded and configured to discharge well through a discharge line and into the wellbore tubing; and
- corresponding check valves for the upper pump chamber arranged such that enlargement and reduction of the volume of the upper pump chamber by corresponding motion of the upper piston will cause fluid to be drawn into the upper pump chamber and discharged therefrom, respectively.
14. The wellbore pump of claim 13 wherein one of the check valves for the lower pump chamber is disposed in an adapter coupled to a lower end of the wellbore pump.
15. The wellbore pump of claim 13 wherein a fluid discharge line couples an outlet of the lower pump chamber to the production tubing located above the wellbore pump.
16. The wellbore pump of claim 13 wherein one of the check valves for the lower pump chamber is disposed in an upper adapter coupling the wellbore pump to the production tubing.
17. The wellbore pump of claim 16 wherein one of the check valves for the upper pump chamber is disposed in the upper adapter.
18. A wellbore fluid pump, comprising:
- a first pump housing coupled to a production tubing by an upper adapter, the upper adapter comprising a check valve disposed therein or in fluid communication therewith, the upper adapter having an internal passage connecting a pumped fluid discharge line to an interior of a check valve seat whereby fluid discharged through the pumped fluid discharge line flows through an internal passage to the check valve and upwardly through the production tubing;
- a power chamber defined within the first pump housing longitudinally between the upper adapter and a power fluid inlet port through the wall of the pump housing, a part of the first pump housing corresponding to the power chamber having an enlarged internal diameter section corresponding to a length of the power chamber;
- a piston disposed within the first pump housing, an upper end of the piston in fluid communication with hydraulic power fluid moved under pressure into the pump housing above the top of the piston through a power fluid passage in the upper adapter;
- a first hydraulic control line coupled to the power fluid passage to enable moving the piston downwardly in the first pump housing;
- a bottom end of the piston comprising a similar fluid seal; and
- a pump chamber defined between the bottom end of the piston within the first pump housing and a lower adapter coupled to a lower end of the pump housing, the lower adapter comprising an intake check valve and a discharge check valve disposed in the lower adapter or in fluid communication therewith.
- a bore through the piston at an upper end to a position on the exterior surface of the piston below dynamic seals on the piston, the bore comprising a relief valve in the bore proximate a top of the piston whereby hydraulic power fluid pressure on a second control line used to move the piston upward in the first pump housing when increased to a pressure higher than operating pressure after the piston reaches the upper end of the pump housing lifts the relief valve followed by opening a corresponding relief valve in the upper adapter to cause trapped gas to exit from the power chamber, through the piston and the relief valves 1710A, 1704A, and then into the production tubing above the upper adapter. Should we add a claim referring to this claim that check valves can be hydraulically coupled to the adapters, but necessarily not mechanically coupled to said adapter? (Thinking that if someone move check valves away from the adapters, but still use such check valves, it is easy to not be in breach with this claim.) Also, should the gas relief function be removed from this claim, as it is included below in claim 20?
19. The wellbore pump of claim 18 further comprising at least one additional pump comprising an upper adapter, a second pump housing, a piston and a lower adapter and check valves coupled at or in fluid communication with the upper adapter to a lower end of the first pump housing.
20. The pump of claim 18 further comprising a gas dump valve coupled hydraulically to a wellbore pump discharge chamber, the gas dump valve operable to release trapped gas by applying hydraulic pressure to the first and second control lines as a pressure above an operating pressure to move the piston.
21. The wellbore pump of claim 18, further comprising a bore through the piston at an upper end to a position on the exterior surface of the piston below dynamic seals on the piston, the bore comprising a relief valve in the bore proximate a top of the piston whereby hydraulic power fluid pressure on a second control line used to move the piston upward in the first pump housing when increased to a pressure higher than operating pressure after the piston reaches the upper end of the pump housing lifts the relief valve followed by opening a corresponding relief valve in the upper adapter to cause trapped gas to exit from the power chamber, through the piston and the relief valves, and then into the production tubing above the upper adapter.
Type: Application
Filed: Oct 19, 2018
Publication Date: Feb 14, 2019
Inventors: Henning Hansen (Dolores), Tarald Gudmestad (Nærbø), James Lindsay (Glasgow)
Application Number: 16/165,478