Reverse Circulator And Method

Abstract

Gravity driven reverse circulator tools are provided and methods of using same. One tool has nested pipes that when fully nested close a hole in one of the pipes, but when the drillstring is lifted, the pipes partially separate under the force of gravity to expose the hole. The other embodiment is similar, but the hole is hook shaped (hook on top as in a walking cane) and a protrusion from the other pipe fits in the hole. Thus, both lifting and rotation are needed open the tool.

Claims

1. A reverse circulator, comprising: a) an inner pipe having a first tool joint at a first end; b) an outer pipe having a second tool joint at a second end; c) two or more holes in one of said inner pipe or said outer pipe; d) said outer pipe assembled around said inner pipe to form a nested pipe assembly such that said first and second tool joints are at a first and second end of said nested pipe assembly, said first end opposite said second end, and said inner pipe is slidingly fitted at least partially inside said outer pipe and thereby reversibly blocking said two or more holes.

2. The reverse circulator of claim 1, said two or more holes being in said inner pipe.

3. The reverse circulator of claim 1, said two or more holes being in said outer pipe.

4. The reverse circulator of claim 1, said two or more holes being in said inner pipe and being slot shaped, said slot shape being parallel with a long axis of said reverse circulator.

5. The reverse circulator of claim 1, having two or more holes being two slots in said inner pipe, said two slots being parallel with a long axis of said reverse circulator and said two slots being 180° apart.

6. The reverse circulator of claim 1, said inner pipe further comprising a first annular ridge on an exterior surface thereof at an end opposite said first tool joint, and said outer pipe further comprising a second annular ridge on an interior surface thereof at an end opposite said second tool joint, said first and second annular ridges preventing complete separation of said inner pipe and said outer pipe.

7. The reverse circulator of claim 1, said first and second tool joint being of differing sizes.

8. The reverse circulator of claim 1, said first and second tool joint being of the same size and said inner pipe further comprising an internal upset or said outer pipe having an external upset.

9. The reverse circulator of claim 1, said inner pipe further comprising an annular ridge on an exterior surface thereof at an end opposite said first tool joint, and said outer pipe further comprising an annular ridge on an interior surface thereof at an end opposite said second tool joint and said first and second tool joints being of a same size and either said inner pipe or said outer pipe having an upset such that said tool joints have said same size.

10. A reverse circulator, comprising: a) an inner pipe having a first tool joint at one end; b) an outer pipe having a second tool joint at one end; c) one or more hook-shaped slots in one of said inner pipe or said outer pipe, said slots oriented along a long axis of said inner pipe or said outer pipe and having a semi-circular curve at a top end of said slots; d) one of said outer pipe or said inner pipe having one or more protrusions on an inner surface near an upper end of said outer pipe or said inner pipe, said protrusions configured to fit into said slots; and e) said outer pipe assembled around said inner pipe to form a nested pipe assembly such that said first and second tool joints are at a first and second end of said nested pipe assembly, said first end opposite said second end, and said inner pipe is slidingly fitted inside said outer pipe with said protrusions in said slots.

11. The reverse circulator of claim 10, said one or more slots being in said inner pipe and said one or more protrusions being on an inner surface of said outer pipe.

12. The reverse circulator of claim 10, said first and second tool joint being of differing sizes.

13. The reverse circulator of claim 10, said first and second tool joints being of the same size and said inner pipe or said outer pipe having an upset such that said tool joints have said same size.

14. A method of reverse circulating in a well, said method comprising: a) providing a drillstring with the reverse circulator of claim 10, above a bottom hole assembly; b) forward pumping fluid down said drillstring with weight on said drillstring until reverse circulation is desired; c) ceasing said forward pumping; d) lifting said drillstring until said inner pipe and said outer pipe partially separate exposing said two or more holes; e) reverse pumping fluid down an annulus outside said drillstring without weight on said drillstring until forward circulation is desired; f) ceasing said reverse pumping; and g) repeating step b) or steps b-f) one or more times.

15. The method of claim 14, said method further comprising rotating said drillstring during reverse pumping.

16. A method of reverse circulating in a well, said method comprising: a) providing a drillstring with the reverse circulator of claim 10 in a closed position above a bottom hole assembly, said closed position being when said protrusions are at an upper terminus of said slots; b) forward pumping fluid down said drillstring with said reverse circulator in said closed position until reverse circulation is desired; c) ceasing said forward pumping; d) lowering and rotating said drillstring until said protrusion meets an uppermost portion of said curve, then lifting and rotating said drillstring so that said protrusions travel to bottom terminus of said slots and said reverse circulator is in an open position; e) reverse pumping fluid down an annulus outside said drillstring with said reverse circulator in said open position until forward circulation is desired; f) ceasing said reverse pumping; g) lowering and rotating said drillstring until said protrusions travel to an uppermost portion of said curve, then rotating and lifting said drill string until said reverse circulator returns to said closed position; and h) repeating step b) or steps b-g) one or more times.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0044] One embodiment of gravity-driven reverse circulator where the lower cylinder is interior to the upper, has holes, and moves with gravity.

[0045] In FIG. 1A there is weight on drill bit and as a result the reverse circulator is closed.

[0046] In FIG. 1B the drillstring is lifted such that weight is off drill bit and the reverse circulator opens as the lower interior cylinder falls in gravity.

[0047] FIG. 1C is a close up of protrusions to prevent inner tube and outer sleeve from completely separating.

[0048] Another embodiment of a gravity-driven reverse circulator with the hole in the outer cylinder.

[0049] In FIG. 2A there is weight on the drill bit and the reverse circulator is closed.

[0050] FIG. 25 is weight off and reverse circulator open as lower interior cylinder falls in gravity.

[0051] Another embodiment of gravity-driven reverse circulator wherein the upper cylinder is interior and has the hole, and the lower exterior cylinder moves.

[0052] FIG. 3A weight on drill bit and reverse circulator closed.

[0053] FIG. 3B weight off drill bit and reverse circulator open as the lower exterior sleeve fall in gravity.

[0054] Another embodiment of gravity-driven reverse circulator, like FIGS. 3A-3B but with the hole on the outer cylinder.

[0055] FIG. 4A weight on drill bit and reverse circulator closed.

[0056] FIG. 48 weight off drill bit and reverse circulator open as the lower exterior sleeve falls in gravity.

[0057] An embodiment of a hook slot reverse circulator that is gravity and rotation driven.

[0058] FIG. 5A shows the two main parts separately.

[0059] FIG. 5B is a cross section through line B-B showing the interior protrusion.

[0060] FIG. 5C shows the parts assembled in the closed (left) and open (right) positions.

[0061] FIG. 6A is a schematic of the cased wellbore with drillstring bringing drilling fluid, usually mud to the BHA, thereby rotating the bit, and return flow up the annulus of the mixture of mud, cuttings and any escaping gas.

[0062] FIG. 68 shows reverse circulation, where fluid is pumped into the annulus, and returns up the drillpipe.

[0063] FIG. 7 show pipe upsets wherein inner or outer diameter changes to accommodate another device.

DETAILED DESCRIPTION OF THE INVENTION

[0064] The disclosure provides novel tools and methods for reverse circulating flow in a well, wherein flow can be reversed a multiplicity of times without sending tools or wire or other signals downhole.

[0065] FIG. 1A shows a lower portion of wellbore that is cased 115 and has drillpipe 101 and BHA (or drillpipe or other tool) 111 below (BHA not detailed herein). The reverse circulator tool is above the BHA 111 and comprises an interior pipe section 109 and an exterior pipe section or sleeve 105. Hole or slot 107 is shown in interior pipe 109, herein in the closed position. The pipe may have 1-6 holes or slots (preferably 2-3) arranged around its circumference depending on size of the tool. Also seen are threaded tool joints 103, but any tool joint could be used to couple the various components. Here the weight is on the drillpipe 101 and bit (not seen) so the weight holds the device closed, and fluid flow (arrows) is in the forward direction.

[0066] It is noted herein that the inner pipe has a jog or upset that allows both ends of the tool to have the same diameter. However, this can be optional where the drillstring about the BHA is of a slightly greater diameter than the drillpipe, tool or BHA below.

[0067] In FIG. 1B, drilling fluid flow is stopped and the drillstring is lifted (heavy up arrow) and the weight of the tool in gravity allows the inner pipe 109 to slide down (heavy down arrow), thus opening the hole 107. Reverse circulation thus becomes possible by pumping fluid into the annulus 113. To again flow in the forward direction, reverse flow is stopped, weight applied to the bit, and fluid pumped into the drillpipe. This can be repeated as often as needed.

[0068] FIG. 1C shows a detail of the two ends of the outer pipe 105 and inner pipe 109 and small protrusions 119, 121 that prevent the parts from separating completely when pulling drillstring out of the hole. Separate protrusions around the circumference of the pipes are possible, but preferably, this is an annular ridge that circumnavigates the pipe and functions even when one pipe rotates with respect to the other.

[0069] FIG. 2A-B is similar, and the numbering is the same except in the 200 series, and thus many parts are not discussed (e.g., 201, 203, 211, 213, 215, 217). Here hole 207 is on the outer pipe 205 instead of the interior pipe 209. We suspect that FIG. 1A may be the preferred embodiment, as the hole is protected from exterior debris while being deployed downhole.

[0070] FIGS. 3A-B and 4A-B are like FIG. 1-2, but the couplings are reversed, the inner pipe 309 connecting to drillpipe 301 above the tool, instead of below the tool as in FIG. 1-2. In FIG. 4A-B the hole position is reversed as in FIG. 2. The numbering system is the same as FIG. 1, being 300 and 400 numbers. Since the parts are otherwise the same, they are not discussed again herein (e.g., 401, 303, 403, 305, 405, 307, 407, 409, 311, 411, 313, 413, 315, 415, 317, 417).

[0071] FIG. 5A shows a perspective view of the separate parts of a different embodiment of a gravity drive reverse circulator that requires both gravity and rotation to function. In this embodiment the inner pipe 505 has a hook slot 503. If desired a plurality of hook slots can circumnavigate the pipe. Here, there are two slots, though only one can be seen. The outer pipe or sleeve 507 is also seen, with line B-B providing a cross section seen in FIG. 5B. Here, two protrusions 509 are seen on the inner surface, and will fit into the two hook slots 503 when assembled such that the two pipes are nested.

[0072] FIG. 5C shows the parts assembled in the closed position (left) with protrusion 509 in slot 503 at the top end of the hook slot 503. To open the slots, the drillpipe is pushed down slightly, and rotated the width of the hook and then lifted, as shown in the right panel. Note that coupling details with pipe above and below are omitted for simplicity, but can be similar to that shown in FIG. 1-4. As with FIG. 1-4, it is possible to put the hook slot 503 on the outer pipe 507, instead of the inner pipe 505 and it is also possible to reverse the pipe joint orientation, giving 4 possible embodiments.

[0073] In this embodiment, the hook size and shape are such as to allow good fluid flow when open, and yet not so large that the tool cannot be compressed with the weight of the drillstring, small amount needed to pen the tool, nor so large that pipe integrity is threatened. If needed, a biasing force can be included in the tool to make this easier, but we do not expect to need this as fluid flow should act as a secondary shifting mechanism.

[0074] The following references are incorporated by reference in their entirety:

[0075] WO2014025797 Switchable fluid circulation tool.

[0076] U.S. Pat. No. 9,708,872 Clean out sub.