CROSS-REFERENCE TO RELATED APLICATIONS This application claims priority to GB Application No. 2503333.3 filed Mar. 7, 2025, the contents of which are incorporated by reference herein in its entirety.
BACKGROUND TO THE INVENTION Specialised downhole pumps are used in the hydrocarbon exploration and production industry in various applications, and in particular for the production of hydrocarbons to surface from significant wellbore depths. There are several types of downhole pump in use, including Electrical Submersible Pumps (ESPs) and Sucker Rod Pumps (SRPs).
An SRP system is powered by a rod extending from surface to the downhole pump, and the stroking action, can be achieved by a “nodding donkey” reciprocating machine, or long stroke hydraulically powered machines. The SRP is also referred to as a reciprocating pump. The downhole pump typically comprises a standing valve and a traveling valve. The standing valve is attached to the tubing. The traveling valve reciprocates with the rod string. Both valves typically comprise a ball check arrangement.
Downhole pumps are sensitive to sands and other abrasive solids being present in the production fluid. The amount of sand which is produced from a well depends on characteristics of the formation, and various methods are used to control sand production. However, it is common for some amount of sand or abrasive solids to be present in the production fluid.
With many production systems which use a downhole pump, problems can arise when the pump is shut down after a period of pumping fluid up the production tubing to surface. When production ceases with an SRP system the fluid column is sustained in the tubing by the stationary valve. The entrained solids in the static fluid column within the production tubing will fall with gravity. The falling sand can accumulate several feet on top of the traveling and stationary valve resulting in abrasion, lost production due to slippage losses, valve blockage, and a stuck pump.
In some cases, a solids fallback protection device can be installed integrally to the rod string above an SRP system. Prior art details a device with multiple chambers with slits intended to capture the falling solids and which also allow fluid to remove solids upon restart of the SRP system.
It is amongst the aims and objects of the invention to provide various methods to prevent the above-described deficiencies of downhole pump systems.
Further aims and objects will become apparent from reading the following description.
SUMMARY OF THE INVENTION This disclosure is directed to systems and methods which will remove solids from fluids and remove solids from the functioning surfaces reducing or eliminating one or more of the problems above with SRP systems. A device with multiple chambers each containing multiple bases with slots and storage volumes will prevent solids from entering a pump and self-clean upon reversing fluid direction in applications involving a sucker rod pump.
The device protects an SRP system from suspended solids in the fluid column by containing and storing these solids before they settle on the SRP system by utilizing a multitude storage chambers with a multitude slotted bases in each chamber; it also self-cleans these solids upon restarting of the SRP system, and provides a continuous fluid communication path through the device.
BRIEF DESCRIPTION OF THE DRAWINGS There will now be described, by way of example only, embodiments of the invention with respect to the following drawings:
FIG. 1 is a diagram illustrating a typical SRP system
FIG. 2 is a diagram of an SRP system with a solids fallback protection device installed
FIGS. 3 is a diagram of a solids fallback protection device with select components in separate isometric views
FIG. 4 are cross sectional diagram of a solids fallback protection device with select components in separate isometric views
FIG. 5 is a cross-sectional diagram of a solids fallback protection device during a downstroke
FIG. 5A are magnified views of a solids fallback protection device during a downstroke
FIG. 6 is a cross-sectional diagram of a solids fallback protection device demonstrating the solids capture function
FIG. 6A are magnified views of a solids fallback protection device demonstrating the solids capture
FIG. 7 is a cross-sectional isometric views of a solids fallback protection device demonstrating the self-cleaning function
FIG. 7A are magnified views of a solids protection device demonstrating the self-cleaning function
DETAILED DESCRIPTION One or more embodiments of the invention are described below. It should be noted that these and any other embodiments described below are exemplary and are intended to be illustrative of the invention rather than limiting.
As mentioned above, solids can enter a downhole pump from the discharge, or settle on top of the pump. A method to measure the stored volume of solids will reduce operating costs. A method to capture, contain and self-clean will also reduce operating costs with SRP systems.
Referring to FIGS. 1 and 2, there is shown a typical SRP system. The main components of the downhole SRP system 120 are a traveling valve 122 attached t to rod string 112 and a stationary valve 121 connected to production tubing string 114. A beam pump 110 on the surface provides a reciprocating linear motion to the rod shaft string 112 which lifts and lowers the traveling valve 122. FIG. 2 illustrates the addition of a solids fallback protection device 250 located between the downhole SRP system 220 and the surface.
Referring to FIG. 3, there is shown a view of a solids fallback storage device and isometric views of select components. View 3.1 shows the solids fallback storage device with cross-sectioned well casing 300, production tubing 305, device housing 350, device top end 320, and device bottom end 390. Rod string 310 connects to device top end 320 and bottom end 390. The device contains a multitude of chamber assemblies 325 in series. Chamber assembly 325 consists of adapter 340, storage tube 360, round pin 355, and a multitude of slotted chamber bases 370 Finned adapter 345 connects round adapter 340 to top end 320 and bottom end 390. Storage tube 360 contains a multitude of holes on the top end 364, holes on the bottom end 362, and vertical slits 366. View 3.2 is an isometric view of round adapter 340 which connects storage tubes 360, directs falling solids out of bottom holes 362, and communicates well fluid in bottom holes 362, and communicates well fluid out of top holes 362. View 3.3 is an isometric view of chamber base 370 with a multitude of vertical slots 375. View 3.4 shows an isometric view of finned adapter 345 which allows fluid and solids to pass.
Referring to FIG. 4, there is shown a view of a solids fallback storage device and isometric views of select components. View 4.1 is a cross-sectional depiction of all components. View 4.1 shows the solids fallback storage device with sectioned well casing 400, production tubing 405, device housing 450, device top end 420, and device bottom end 490. Rod string 410 connects to device top end 420 and bottom end 490. The device contains a multitude of chamber assemblies 425 in series. Chamber assembly 425 consists of adapter 440, storage tube 460, round pin 455, and a multitude of slotted chamber bases 470 Finned adapter 445 connects round adapter 440 to top end 420 and bottom end 490. Storage tube 460 contains a multitude of holes on the top end 464, holes on the bottom end 462, and vertical slits 466. View 4.2 is an isometric view of round adapter 440 which connects storage tubes 460, directs falling solids out of bottom holes 462, and communicates well fluid in bottom holes 462, and communicates well fluid out of top holes 462. View 4.3 is an isometric view of chamber base 470 with a multitude of vertical slots 475. View 4.4 shows an isometric view of finned adapter 445 which allows fluid and solids to pass.
Referring to FIG. 5, there is shown a cross-sectional view of a solids fallback storage device during a downstroke. The stationary valve of the downhole pump supports the fluid column within production tubing 505. Arrows 512 depict the downstroke motion of the rod string 510 and fallback storage device resulting in well fluid 515 relatively moving around and inside the device. Well fluid 515 enters the device passing through bottom end 590 and finned adapter 545, entering the volume within device housing 550, then diverging into the storage tube 560 inner diameter through holes 562 and through slotted chamber bases 570. The well fluid 515 inside the storage tube 560 encounters round adapter 540 which directs well fluid 515 out of holes 564. The fluid repeats the flow path with each storage chamber 525 in series until passing through finned adapter 545 and top end 520 before exiting the device. View 5.1 and view 5.2 are shown on FIG. 5A.
Referring to FIG. 5A, there are shown magnified cross-sectional views of a solids fallback protection device during a downstroke. View 5.1 depicts a magnified view centered around communication ports 564 on the top portion of storage tube 560. Mobilized well fluid 515 travels in the annular space between production tubing 505 inner diameter and device housing 550 outer diameter, the annular space between device housing 550 inner diameter and storage tube 560 outer diameter. Well fluid traveling in the inner volume of storage tube 560 encounters round adapter 540 which directs fluid through communication ports 564 and into the annular space between device housing 550 and storage tube 560 outer diameter. View 5.2 depicts a magnified view centered around communication ports 562 on the bottom of the storage chamber. Mobilized well fluid 515 travels past finned adapter 545 and in the annular space between production tubing 505 inner diameter and device housing 550 outer diameter. The traveling fluid 515 in the annular space between device housing 550 inner diameter and storage tube 560 outer diameter encounters storage bases 570. The resulting back pressure pushes well fluid 515 to enter storage tube 560 inner volume through communication ports 562.
Referring to FIG. 6, there is shown a cross-sectional view of a solids fallback storage device with two storage chambers 625 when the fluid production has stopped and suspended solids fall with gravity. The stationary valve of the downhole pumps supports the static fluid column within the production tubing 605. View 6.1 depicts falling solids 617 falling around rod string 610 and entering the device through top end 620 and finned adapter 645. Round adapter 640 deflects the solids 617 to the annular space between device housing 650 inner diameter and storage tube 660 outer diameter. Storage base 670 stops the solids from falling to the next chamber 625 below. The level of contained solids 619 elevates until the contained solids fall through holes 664 in storage tube 660 entering the inner diameter of storage tube 660. These solids fall encountering round adapter 640 which directs the solids through holes 662 and deflects the solids to the annular storage space between the device housing 650 inner diameter and the storage tube 660 outer diameter. The falling sand 617 and contained sand 619 repeat the process with each chamber in series. View 6.2 depicts a magnified view of the storage bases 670 with misaligned slots 670 affixed to storage tube 660 within device housing 650. Sand 618 enters the slot 675 of the top storage base 672. Upon encountering the middle storage base 674 the solids 618 stop falling further. Bottom storage base 676 offers redundant protection from solids 618 traveling further in the device. Alternatively, the device has one or a multitude of storage chambers. A further alternative may utilize a round adapter 640 with a flange that does not protrude past the outer diameter of storage tube 660. A further alternative may utilize a multitude of storage bases 670 in each storage chamber 625.
Referring to FIG. 6A, there are shown magnified cross-sectional views of a solids fallback protection device with solids being captured during idle fluid production. View 6.3 depicts a magnified view centered around communication ports 664 on the top portion of storage tube 660. Contained solids 619 accumulate in the annular space between device housing 650 inner diameter and storage tube 660 outer diameter until reaching the height of communication ports 664 when falling solids 617 enter the inner volume of storage tube 660. View 6.4 depicts a magnified view centered around communication ports 662 on storage tube 660, below storage bases 670 and above round adapter 640. Falling solids 617 encounters round adapter 640 which directs the falling solids 617 through communication ports 662 and into the annular space of the subsequent storage chamber’s annular volume between device housing 650 inner diameter and storage tube 660 outer diameter.
Referring to FIG. 7, there is shown a cross-sectional view of a solids fallback storage device in self-cleaning mode during a downstroke. The stationary valve of the downhole pump supports the fluid column within production tubing 705. Arrows 712 depict the downstroke motion of the rod string 710 and fallback storage device resulting in well fluid 715 relatively moving around and inside the device. Mobilized fluid 715 entrains solids 717 contained in the device. Well fluid 715 enters the device passing through bottom end 790 and finned adapter 745, entering the volume within device housing 750, then diverging into the storage tube 760 inner diameter through holes 762 and through slotted chamber bases 770. The well fluid 715 inside the storage tube 760 encounters pin 755 creating a back pressure which pushes fluid through slits 766 entraining solids 717 located in the annular space between device housing 750 inner diameter and storage tube 760 outer diameter. The well fluid 715 above pin 755 within storage tube 760 encounters round adapter 740 which directs well fluid 715 and solids 717 out of holes 764. Fluid 715 and solids 717 repeat the flow path with each storage chamber 725 in series until passing through finned adapter 745 and top end 720 before exiting the device.
Referring to FIG. 7A, there are shown magnified cross-sectional views of a solids fallback protection device with solids being removed upon the resumption of well fluid production. View 7.1 depicts a magnified view centered around communication ports 764 located on the top portion of storage tube 760. Well fluid 715 mobilizes solids 717 and travels in the annular volume between production tubing 705 inner diameter and device housing 750 outer diameter and the annular volume between device housing 750 inner diameter and storage tube 760 outer diameter. Well fluid 715 traveling in the inner volume of storage tube 760 encounters round pin 755 creating a backpressure which pushes well fluid 715 through slits 766 in storage tube 760 into the annular volume between device housing 750 inner diameter and storage tube 760 outer diameter mobilizing contained solids. Well fluid 715 traveling in the inner volume of storage tube 760 encounters round adapter 740 which directs the well fluid 715 through communication ports 764 and into the annular volume between device housing 750 inner diameter and storage tube 760 outer diameter. View 7.2 depicts a magnified view centered around communication ports 762 located on the bottom portion of storage tube 760. View 7.2 depicts a magnified view centered around communication ports 762 located on the bottom portion of storage tube 760. Well fluid 715 travels in the annular volume between production tubing 705 inner diameter and device housing 750 outer diameter, and travels through finned adapter 745 entering the annular volume between device housing 750 and storage tube 760 outer diameter. Backpressure occurs upon encountering storage bases 770 which pushes well fluid through communication ports 762 into the inner volume of storage tube 760 and mobilizing solids 717.
