CROSSOVER TOOL

[0001] The field of this invention is crossover tools frequently used in gravel packing operations and features of such tools post gravel packing, which allow chemical treating or packer inflation.

[0002] Crossover tools are frequently used in performing gravel-packing operations. They allow the gravel to pass through a packer and exit to an annular space outside one or more screens. The returns pass through the screen up a wash pipe and back through the crossover and out into the annulus above the packer for the trip to the surface. After deposition of the gravel, the crossover tool is picked up so that remaining gravel in the tubing can be reversed out with fluid pumped down the annulus above the packer.

[0003] Following gravel pack operation, the need may arise to acid treat the gravel pack area around the screens. In the past the gravel packing service tool assembly, including the crossover had to be pulled out and the treating string run in. The present invention presents a crossover tool with modifications to allow pumping down the string through the crossover tool, after the gravel packing operation is concluded so as to eliminate a trip out of the hole for acid treating. It also allows the excess chemical to be reversed out using a unique assembly that captures a plug that was used to shift a sleeve, on that sleeve during reverse flow.

[0004] In prior gravel packing techniques that used isolators in conjunction with the screens, it was also the practice to pull the gravel packing assembly, including the cross-over, and run in with another string to selectively inflate the external casing packers in the gravel pack zone. The present invention with the access provided through the crossover tool after the gravel packing allows such packers to be inflated in the same trip. This prior two-trip procedure is illustrated in U.S. Pat. No. 6,311,772. With the present invention the technique described in that patent can be streamlined.

[0005] Relevant patents that show gravel packing or sliding sleeve devices in downhole tools are U.S. Pat. Nos.: 2,994,280; 4,424,864; 4,427,070; 4,520,870; 5,411,095; 5,597,040 and 5,823,254.

[0006] Those skilled in the art will be better able to appreciate the value of the invention from a description of the preferred embodiment and the claims below.

[0007] A crossover tool is disclosed that permits access through to the wash pipe below after the conclusion of a known gravel packing operation. A ball is trapped to a sleeve after shifting it so as to allow flow through the crossover for acid treatment in the screen area and a reversing out procedure to remove excess acid. Alternatively, pressure delivered through the wash pipe can operate packers, as part of a gravel packing procedure as outlined in two steps in U.S. Pat. No. 6,311,772 is a single trip. The acid treating or other downhole operation through the wash pipe can also be accomplished in a single trip with the gravel packing assembly.

[0008] FIG. 1 is an elevation view of the crossover in the gravel packing operation;

[0009] FIG. 2 is the view of FIG. 1 with the upper ball dropped after the conclusion of the gravel packing operation;

[0010] FIG. 3 is the view of FIG. 2 showing the flow for treating or other downhole operation through the crossover after gravel packing;

[0011] FIG. 4 is a close-up of the ball approaching the upper seat;

[0012] FIG. 5 is the view of FIG. 4 with the ball passing the upper seat and moving into contact with the sliding sleeve;

[0013] FIG. 6 is the view of FIG. 5 with pressure applied on the ball to shift the sleeve;

[0014] FIG. 7 is the view of FIG. 6 with pressure coming from below and showing the ball trapped by the upper seat;

[0015] FIG. 8 is a close-up view of the crossover during the gravel packing operation;

[0016] FIG. 9 is the view of FIG. 8 with the ball past the initial seat and trapped against the sliding sleeve;

[0017] FIG. 10 is the view of FIG. 9 showing the sleeve assembly shifted to permit the downhole operation through the crossover after gravel packing;

[0018] FIG. 11 is a view of the crossover during a subsequent operation below it in a single trip and showing the position of the wash pipe with respect to the packer.

[0019] FIG. 1 shows the crossover of the present invention in the gravel packing position. A ball 10 is dropped onto a seat 12. The gravel is pumped through a packer (not shown) through which the crossover tool 14 extends. The gravel goes down passage 16 and out lateral port 18. Returns come through the screen (not shown) and into ports 20 just below ball 10. The flow is through an annular passage 22 in the crossover tool 14 and out above the packer (not shown) through ports 24 as indicated by arrows 26. In this manner, the crossover tool 14 accomplishes gravel deposition in the manner previously known.

[0020] FIG. 2 shows the ball 28 having been dropped down. That sequence is more clearly shown in FIGS. 4-7. In FIG. 4, the ball 28 lands on a thin sleeve 30 which acts as the initial ball seat. Upon pressure buildup, the ball 28 is forced past sleeve 30 and into sealing contact with seat 32 on sleeve 34. Sleeve 34 is an extension of sleeve 30. A shear pin 36 holds sleeve 34 in its initial position. A snap ring 38 is mounted to sleeve 34 and it is able to snap out into recess 40 when sleeve 34 shifts as a result of applied pressure to ball 28 when on seat 32. This movement is shown in FIG. 6. As a result of this movement, the internal diameter of sleeve 30, through which ball 28 has already been forced, is further reduced as it is pulled through a reduced diameter of a surrounding body 42. The ball 28 is locked onto seat 32. FIG. 7 shows pressure from below to a predetermined level, cannot dislodge the ball 28. This can occur during a reversing out procedure after an acid treatment or some other downhole procedure, as will be explained below.

[0021] FIGS. 8-10 illustrate the normal gravel packing position and subsequent positions. These Figures show in detail portions for the crossover tool 14 illustrated in FIGS. 1-3. In the gravel-packing step, the ball 10 (see FIG. 1) is in position and gravel is pumped down passage 16. Eventually the gravel exits port 18 (see FIG. 1) and the returns go through the screen (not shown) into a wash pipe 44 and into annular passage 22 to exit at ports 24. Ports 24 are located above a packer (not shown) and the returns from gravel packing go to the surface in the annulus above this packer. FIG. 8 also indicates the position of thin sleeve 30, seat 32, sleeve 34, shear pin 36, snap ring 38, and recess 40. FIG. 9 shows that when the sleeve 34 is displaced due to pressure on ball 28, it bottoms on shoulder 46 on sleeve assembly 48. After buildup of sufficient pressure on ball 28, sleeve 34 takes sleeve assembly 48 with it, as shear pin 49 shears, to open passages 50 into annular passage 22, through passages 51, and to close ports 24. The shifted position is secured by keeper ring 53 expanding past the stop ring 55. Referring to FIGS. 3 and 10, flow can come from the surface through the tubing (not shown) that supports the crossover 14 and into passages 50 as shown by arrows 52. Referring to FIG. 3, the flow continues down annular passage 22 to ports 20, as indicated by arrows 52. Flow then goes through the wash pipe 44 to the area of the screens (not shown). Those skilled in the gravel packing art will readily see that in a single trip, the gravel packing can be accomplished in the previously done manner and that access to the screen area is obtainable for acid treating or for inflation of external packers into the gravel pack or for other downhole operations which require flow through the crossover tool 14. The single trip capability comes from not having to pull the crossover tool 14 after the gravel pack to gain access to the screen area through the wash pipe.

[0022] If doing an acid treatment, it may be desirable to reverse out any excess acid. To do this, the crossover tool 14 is picked up out of the packer, just like when the ball 28 is first dropped onto sleeve 30, so that only the wash pipe 44 is still in the packer P, shown schematically in FIG. 3. Reverse flow, indicated by arrows 54 comes down outside the crossover tool 14 and goes down into and back up through the wash pipe 44. It should be noted that the reversing flow, indicated by arrows 54 has to go right past openings 18. It would normally enter there and go up hole through passage 16, except for the fact that ball 28 is sealingly retained against seat 32 to prevent uphole flow (see FIG. 7). What happens is that the reverse flow shown by arrow 54 forces ball 10 down against its seat 12 and the reverse flow path is now in the opposite direction as arrows 52 after entering the wash pipe 44. In essence, the reverse flow bypasses trapped ball 28 as it re-enters passage 16 above it for the trip to the surface. Ball 10 is held against its seat 12 by a higher pressure above it than the returning flow represented by arrow 54, which comes in below it.

[0023] Different pressure levels on ball 28 can trigger the described movements. For example at 200-500 pounds per square inch (PSI), ball 28 will go through sleeve 30. At 750-800 PSI the snap ring 38 will go into recess 40 trapping ball 28. At 1400-1600 the sleeve assembly 48 will move down after breaking shear pins 49 opening passages 50, to get access to annular passage 22 through passages 51. Other non-overlapping pressure ranges can be used.

[0024] FIG. 11 is an illustration of access through the crossover tool 14 after dropping trapping and shifting ball 28. It shows the wash pipe 44 lifted up with respect to packer P to open return passage 45 when performing a downhole treatment or other task through the crossover tool 14 after gravel packing and without an addition trip into the hole. Those skilled in the art will appreciate that a variety of tasks can be done below the crossover tool 14 after gravel packing without another trip into the hole.

[0025] While the preferred embodiment has been described above, those skilled in the art will appreciate that other mechanisms are contemplated to accomplish the task of this invention, whose scope is delimited by the claims appended below, properly interpreted for their literal and equivalent scope.