Abstract
A downhole apparatus for collecting solids fallback in the tubing of an oil producing borehole comprises two or more baskets to collect the solids fall back, each basket partially occupying a portion of the inner cross section of the tubing, leaving a portion of the inner cross section of the tubing having an unrestricted flow path. The baskets when considered in plan view along longitudinal axis of the tubing are distributed such that together they cover substantially the whole area of the tubing while leaving an unobstructed non-straight flowpath around the baskets.
Claims
1. A downhole apparatus to collect solids fallback in the tubing of an oil producing borehole comprising two or more baskets to collect the solids fall back, each basket partially occupies a portion of the inner cross section of the tubing, leaving a portion of the inner cross section of the tubing having an unrestricted flow path, the baskets when considered in plan view along longitudinal axis of the tubing are distributed such that together they cover substantially the whole area of the tubing while leaving an unobstructed non-straight flowpath around the baskets.
2. An apparatus according to claim 1 wherein the baskets are fabricated from a filter material.
3. An apparatus according to claim 1 wherein the baskets are arranged to collect fall back solids from different sectors of the tube, the baskets may overlap each other in terms of coverage.
4. An apparatus according to claim 1 wherein the bottom of the basket includes a filter or a flapper valve of filter material construction, such that in the event of a surge of solids the flapper can open to provide virtually full bore flow until the surge has passed.
5. An apparatus according to claim 1 wherein the downhole apparatus may form a part of a hydrocarbon production system, and may be used during production of hydrocarbons.
6. An apparatus according to claim 1 wherein the downhole apparatus is part of a rod lift pump system having a pump plunger, and incorporated into the pump plunger body.
7. An apparatus according to claim 1 wherein the downhole apparatus is part of a rod lift pump system, and the baskets are arranged to fit onto a joint of a rod lift shaft, and arranged to collect any solids fallback.
8. An apparatus according to claim 1 wherein the baskets include a sintered mesh filter.
9. An apparatus according to claim 1 wherein the baskets include a wire screen filter.
10. An apparatus according to claim 1 wherein the filter gap is created by an injection moulding process.
11. An apparatus according to claim 1 wherein the baskets include ceramic V shaped bars with the gap width.
12. An apparatus according to claim 1 wherein the baskets include a combination of V shaped bars and round rods, the rod rods lift off from the V seat to provide a large flow area up and then sit down the V shape bars in reverse flow and have minimum or no flow back
13. An apparatus according to claim 1 wherein each basket includes a filter of different mesh size.
14. An apparatus according to claim 1 wherein the apparatus is incorporated in an artificial lift production system comprising one or more downhole pumps located below the apparatus.
15. An apparatus according to claim 1 wherein the apparatus is also tie through tubing deployable and retrievable.
16. An apparatus according to claim 1 wherein the apparatus is installed with a pump inlet, and inverted to collect solids before they enter the pump.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] There will now be described, by way of example only, embodiments of the invention with respect to the following drawings,
[0037] FIG. 1 is a section side view of tubing in a well with one embodiment of the complete apparatus installed inside it.
[0038] FIG. 2 is a section side view of one embodiment of the invention
[0039] FIG. 3 is a section plan view of FIG. 2
[0040] FIG. 4 is a section side view of another embodiment of the invention incorporating a flapper valve in the bottom of the basket of the tool
[0041] FIG. 5 is a section plan view of FIG. 4 with the flapper valve shown closed (the flapper valve having filter flow through passages in its construction
[0042] FIG. 6 is a section plan view of FIG. 4 with the flapper valve shown open
[0043] FIG. 7 is a section side view of tubing in a well with another embodiment of the complete apparatus installed inside it deployed on slickline and suspended in the tubing using a commercially available hanger (22).
[0044] FIG. 8 is a section side view through a rod lift pump, with the apparatus installed inside the plunger body
[0045] FIG. 9 is a section side view of a well bore production tubing with a rod lift string installed inside it.
[0046] FIG. 10 is a similar view to FIG. 9 with the rod lift joint centralised at both ends and solid fall-back baskets located on the rod lift shaft.
[0047] FIG. 11 is a plan view of another embodiment of the invention
[0048] FIG. 12 is a side view E of FIG. 11
[0049] FIG. 13 is a side view G of FIG. 12
[0050] FIG. 14 is a plan view F of FIG. 13
[0051] FIG. 15 is a table showing details of typical configurations, dimensions, solid fall-back storage volumes etc.
[0052] FIG. 16 is a section side view through another embodiment of the invention.
[0053] FIG. 17 is detail A of FIG. 16
[0054] FIG. 18 is end section view OD of FIG. 17
[0055] FIG. 19 is end section view EE of FIG. 17
[0056] FIG. 20 is a similar view to FIG. 17 with sand fallback being collected in the side basket
[0057] FIG. 21 is a side view of FIG. 17
[0058] FIG. 22 is a isometric view of the two shelfs shown in FIG. 17
[0059] FIG. 23 is a section side view through another embodiment of the invention
[0060] FIG. 24 is an orthogonal side view of FIG. 22
[0061] FIG. 25 is an end view of FIG. 24
[0062] FIG. 26 is a similar view to FIG. 25 in a folded position
[0063] FIG. 27 is a section side view of two of the components shown in FIG. 23, each orientated 180 degrees with each other
[0064] FIG. 28 is a rendered view similar to FIG. 27, with the addition of a centraliser
[0065] FIG. 29 is a blown-up view of detail G
[0066] FIG. 30 is a section side view through a shelf with another embodiment of the filter
[0067] FIG. 31 is a similar view to FIG. 30 with flow in the reverse direction
[0068] FIG. 32 is a plan view of a continuous V wire screen
[0069] FIG. 33 is a section side view of the continuous V wire screen shown in FIG. 32
[0070] FIG. 34 is a side view of the continuous V wire screen shown in FIG. 32
[0071] FIG. 35 is a section side view of the shelf with the screen shown in FIG. 32 inserted into the horizontal slot.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0072] Referring to FIGS. 1 to 6, there is shown production tubing , a check valve 2 and a knock off circulation port 3 Inside the joint of tubing, is mounted modules 4 which consist an upper ring 5 a lower ring 6 an internal bore 7 in lower ring in which the reduced diameter 8 of the upper rig fits, this enables these modules to be stacked together. A basket compartment with an open top 9 into which solids can fall into the basket, and sides of straight cord 10 and circumference 11 and the base 12. The mesh size of the basket is selected to trap the solids in the produced fluid, and could 50 mesh to 100 mesh or any other preferred mesh size. The lower surface of the basket could also incorporate a flapper type valve 13 with ports 14 and a mesh 15 in the port, in normal operation the flapper will be flat to the bottom of the basket, but, in the event of a surge of solid slurry, it would be advantageous for the flapper to open and provide virtually full bore flow area 16 for the slurry to flow through. The normal flow path 17 is always open. To protect the basket from erosion, a deflector 18 could be fitted which would direct flow to the flow passage 17, and protect the lower surface of the basket 19, it would have slots in it so allowing the passage of fluid during solids fallback. Ideally, the modules are stacked on top of each other, and when solids fall back, initially the upper basket 20 fits, any solids that by pass it fill the next basket down 21, and this is repeated to basket 22, 23, 24, 25 etc.
[0073] Referring to FIG. 7, the system could also be deployed riglessly, the modules described above could be connected together and conveyed into a well using slickline and suspended in the well using a commercially available tool 22. This is available from a company called D&D International, it is called a AD-2 tubing stop and can be used in any tubing string. The AD-2 tubing stop can be set any place in the tubing string with a nominal tubing ID. It can also be used as a slick line-retrievable anchor. The AD-2 tubing stop is held in the set position by slips that engage the tubing wall. When installing the AD-2 tubing stop, the appropriate GS pulling tool and the attached stop are lowered into the tubing string using standard slick line methods. The AD-2 tubing stop can be set by simple manipulation of the wireline which shears the pin and the spring forces the slips onto the cone locking the tubing stop in place. The tubing stop body, which contains the slip cone, is driven tightly behind the slips by heavy downward jarring. When removing the AD-2 tubing stop, upward jarring with the appropriate GS pulling tool causes the slips to release and allows the tubing stop to be pulled to the surface.
[0074] It is attached to the upper most module 30 top of assembly via an adaptor 31 which has a threaded box connection 23 on its lower end and a threaded connection 32 on its upper end which attaches it to the AD-2 assembly 22. Passages 33 in the adaptor allow the flow from the module passages 34 into the internal bore 35 of the AD-2 tool and into the production tubing 36 above the AD-2.
[0075] Referring to FIG. 8 there is shown a section side view of a rod lift type pump. The rod 40 from surface attaches to the top of the plunger 41, at the top of the plunger is a series of funnels described in an earlier patent application. The plunger sits inside a static pump barrel, at the lower end of the pump barrel is a static non return valve 43. At the bottom of the plunger piston is a travelling non return valve 44. The modules 4 described earlier could reside inside the plunger piston and could collect the fall-back solids and prevent them from falling onto the travelling non-return valve 44.
[0076] Referring to FIGS. 9 and 10, there is shown a section through the production tubing 50 somewhere between the pump and surface. Inside the production tubing is a rod lift string 51, and this is reciprocated up and down to operate the downhole pump. If ceramic or other material centralisers 52 are placed at the top and bottom of a rod, then for that section of production tubing the rod will be perfectly centralised. Attached to the rod would be simple baskets 53 which would only occupy one side of the tubing/rod annulus 54 while the other side 55 would be clear for production fluid to freely flow. The baskets would be placed on alternate sides 56,57 so as to capture all the solids fall back in the event of a pump shutdown.
[0077] Referring to FIGS. 11 to 14 there is shown another embodiment of the invention. It consists of two side frame members 60,61. The side frames act as a structural member to which everything else is attached. To make a basket, a straight mesh screen 62 encloses the central line, the inner surface of the tubing 63, is the outer surface of the basket, and a flat half circle plate 64 which has a close fit to the tubing 63 and attaches to the frames 60,61 provides the bottom of the basket. The plate 64 could have a fixed mesh screen, or it could have a flapper valve type screen 65 hinged by pins 66, for the reason previous described.
[0078] Referring to FIG. 15, this is a table with different tubing sizes, rod sizes and baskets dimensions providing an indication of the solids storage capability of the device, and for an arbitrary number of baskets what the overall storage capacity is vs what a typical volume of solids are in a production fluid. These figures are only for helpful comparison as real well figures can vary significantly.
[0079] Referring to FIGS. 16 to 22 there is shown another embodiment of the invention. It consists of a lower connection 70 which connects to the discharge side of the pump, an upper connection 71 and a tubular housing 72. Inside the tubular member 72 is a vertical member 73, consisting of three layers, two outer layers 74,75 and an inner sandwich layer 76. Attached to the vertical sandwich layer are crescent shaped shelfs 77, these create a closed chamber 78, at the bottom of this chamber is the shelf 77 and in this shelf is a passage 79 and midway in this passage is a filter 80 of a selected mesh size, this allows the flow of fluid in the upward direction 81 through the chamber 78. Fluid flow up can also flow through the large passage 82 of the vertical sandwich assembly along the crescent flow path with no shelf 83 to another opening in the vertical sandwich 85. In the event of a shut down, fluid above the pump will fall down 86 through this device, through the pump and equalise with the fluid in the tubing annulus. Any solids 87 in the flow will collect in the closed chamber 88 and be stored there, preventing them from going into the pump discharge. Along the vertical side of the chamber are passages and filter material 89, also to help solids flow into the catchment chambers a helical flow generator 91 makes to returning solids flow in a spiral path. When pumping is recommenced, fluid will flow up following the easiest path 90, it will also flush clean the solids stored in the closed chamber 88, by flowing into the filter path 89 and 80. It will be appreciated that the solids produced with the production fluid can be different mesh sizes, so it may be advantageous to have different mesh sizes for the different shelfs, foe example, for a 12 shelf device, the upper two shelfs could be 40 mesh, the next two 60 mesh, the next two 80 mesh, the next two 100 mesh, the next two 120 mesh and last two 140 mesh
[0080] Referring to FIGS. 23 to 29 there is shown another embodiment to the sucker rod pump solids capture device. It consists of an injection moulded part. It has two halves, 100 and 101, which when folded together form a crescent shaped basket 102 which occupies about half the production tubing flow area. At the lower end of the basket thin slots have been created in the bottom of the basket, by the action of the moulding tool. A V shape tool or die from the outside creates V shaped grooves 103 on the outer most lower side of the bottom of the basket, and a V shaped inner die or tool creates V shaped grooves on the inner side of the top face of the bottom of the basket 104. The tips of 103,104 of the dies touch each over and after the moulding process, the width of the tips equal the size of mesh. i.e 40 mesh is equal to 0.0165″, 70 mesh is equal to 0.0083″ and 100 mesh is equal to 0.0059″. Using such opposing dies with V-shaped section grooves produces a mesh parallel screen bars; a mesh having cross bars may be produced by opposing dies having corresponding truncated pyramid features, the mesh size being determined by the size of the truncated apex of the pyramid portions of the dies.
[0081] An interlocking feature 105 locks the two halves together once folded together. The inner diameter 106 is sized to clip around the sucker rod 107, and once clipped onto the rod, cannot come away freely as it circumference extends beyond the centre line of the rod. At each end of the basket are two long spacers 107,108, which provide a spacing to connect more than one of these assemblies to another. When two or more assemblies are paired together, they are 180 degrees relative to each other, as shown by 110,111. At there overlap they have a recess that forms a 360 channel 112 into which a clamp 113 can be installed to lock the two parts to the sucker rod. At the top an bottom of the rod a centraliser 114 is fitted to provide a stand off and protect the baskets from rubbing against the internal surface of the production tubing.
[0082] Referring to FIGS. 30 to 34 there are shown some further embodiments to the shelf filter screen. In one embodiment, the screen will consist of triangle shaped bars 120, with round bars 121 situated between them, when flow is coming up from the pump, the round bars 121 lift off from the angular face 122 and provide a large flow area 123 to better flush the basket storage area 124. In flow shut down the rods 121 would fall down and come to rest on the angular surface 122, this could be then zero flow back or have slots or grooves etc (not shown) to allow non or controlled return flow. Alternatively, a frame 130 could allow a continuous triangular wire 131 to be wrapped around it to form a filter screen on both the top side and lower side of the frame. This could be inserted into the slot 132, of the crescent shaped shelf 133.
