Gravel packing method for multilateral well prior to locating a junction

A lateral is gravel packed without a junction in place in a single trip into the wellbore. A disconnect is provided between the isolation packer in the lateral and a main bore packer. The inner string assembly in the gravel packing completion releases a disconnect with a shift tool and then releases the main bore packer so that the inner string assembly takes out the main bore packer and the upper portion of the disconnect when pulling out of the hole. A junction is then placed into the main and lateral legs with a packer having a seal bore into which the production string is sealingly stabbed to produce out of the main bore and/or the just completed lateral.

FIELD OF THE INVENTION

The field of the invention is gravel packing and more specifically gravel packing a lateral before placing a junction in position so that a larger completion can be used in the lateral before placement of the junction at the lateral.

BACKGROUND OF THE INVENTION

Multilateral wells are used to continue or enhance production from a well into a given formation or into several formations. Typically a whipstock in placed in the main bore and properly oriented and a series of mills form a window or opening in the cased hole to initiate the lateral. The window mills can then be removed, a junction placed at the lateral to connect the main bore and the lateral window just opened and the lateral fully drilled. Subsequently, the lateral is completed with a gravel packing assembly that includes sections of screen supported by an isolation packer that is run in with an inner assembly that includes a wash pipe, a crossover and a shifting tool. After the gravel packing is completed, the inner string is removed and a production string is tagged into the isolation packer and production commences.

One of the problems with this order of events in placing the junction in position and running the bottom hole assembly for gravel packing through the junction is that the presence of the junction limits the size of the completion equipment, which then can limit the rate of subsequent production from the lateral. The present inventions overcomes this problem by running in a bottom hole assembly into the lateral and performing the gravel packing without the junction in position. Instead a main bore packer is provided in the string above the isolation packer that prevents getting gravel in the main bore. A disconnect is placed between the main bore packer and the isolation packer in the lateral. The gravel packing of the lateral without the junction in position can also be accomplished in a single trip because the main bore packer can be brought out with the inner string in the lateral to save rig time. These and other aspects of the present invention will be more apparent to those skilled in the art from a review of the specification and associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.

Locking tools are sold by Baker Hughes Incorporated under the names AF and HF Sur-Set Top No-Go Lock Assembly. Baker Hughes also sells Liner Setting Tools with a release feature such as the HRD-E model.

A combination whipstock and seal bore tool that is installed in a single trip is described in U.S. Pat. No. 7,905,279.

SUMMARY OF THE INVENTION

A lateral is gravel packed without a junction in place in a single trip into the wellbore. A disconnect is provided between the isolation packer in the lateral and a main bore packer. The inner string assembly in the gravel packing completion releases a disconnect with a shift tool and then releases the main bore packer so that the inner string assembly takes out the main bore packer and the upper portion of the disconnect when pulling out of the hole. A junction is then placed into the main and lateral legs with a packer having a seal bore into which the production string is sealingly stabbed to produce out of the main bore and/or the just completed lateral.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1illustrates a lateral10that has been conventionally drilled through casing12in main bore14. The main bore14continues as open hole16and for illustrative purposes shows a gravel pack assembly18that has screens20near the lower end as part of an outer assembly supported from isolation packer/hanger22located in the cased portion of the main bore14. Above the packer/hanger22is a combination anchor and seal sub24into which is a whipstock26of the type described in U.S. Pat. No. 7,905,279. All theFIG. 1completion equipment is known in the art and is optionally shown there for illustrative purposes. Those skilled in the art realize that another completion or no completion can be in the main bore except for example equipment that will later accept a junction as will be described below. For Example, the seal sub24that has an anchor feature can be there without the whipstock26such that a junction can be connected directly as will be described below.

InFIG. 2the lateral now has a gravel packing assembly30that for the most part has conventional elements such as a screen assembly32, a crossover11and an isolation packer34among other stock components. An inner string36extends through the assembly30and through a new component in the assembly30which is a disconnect38that will be described in detail below. The inner string36, apart from supporting the assembly30also supports a main bore packer40and a spacer42that allows the proper placement of the seal bore44associated with the disconnect38in the lateral10and the main bore packer40in the main bore14. A running and setting tool46is associated with the main bore packer40for setting it and releasing from it. Isolation packer34is conventionally set such as by dropping a ball on a seat, not shown, and pressuring up. In fact both packers34and40can be set at the same time that way. The gravel packing of the lateral10begins after it is ascertained at the surface that the inner string36is clear to move relative to the outer assembly that includes the screens32and the isolation packer34that supports the screens32. The gravel slurry can be deposited outside the screens32with the carrier fluid forced into the formation in the lateral10. Excess gravel can be reversed out after the disconnect48is parted and the main bore packer40is released in a procedure that is known in the art. The purpose of the main bore packer40is to isolate the main bore14from the lateral10during the gravel packing.

InFIG. 3the inner string36has been raised to release the disconnect48and then the packer40while leaving packer34set. The inner string36now takes with it the packer40and the upper half of the disconnect48leaving exposed a seal bore44.FIG. 4shows the exposed seal bore44after the packer40and part of the disconnect48are removed with the inner string36. InFIG. 5a string52supports a retrieval tool50to attach to a window in the whipstock26to remove it and expose a seal bore54.

FIG. 6illustrates a junction60having a leg62initially stabbed into seal bore44and through the use of known positioning tools the other leg64is stabbed into seal bore54. The hanger/packer70having a seal bore72is shown in the set position and the running string that delivered the junction60has been removed. A production string can be stabbed into seal bore72and the main bore14and/or the lateral10can then be produced individually or together.

FIG. 7shows the disconnect80having an upper portion82and a lower portion84. Dogs86are in windows88in the upper portion82and extend into conforming recesses90in the lower portion84. A sleeve92has a groove94in which resides a snap ring96that is biased into a surrounding groove98in the upper portion82. A portion of the inner string36passes through the sleeve92and has a shoulder100that on upward movement engages the sleeve92for tandem movement. Such tandem movement breaks shear pins91and brings surface102even with the dogs86to allow them to move out of groove90as shown inFIG. 8. At the same time the snap ring96snaps into groove104to lock the position of sleeve92in theFIG. 8position. At this point the inner string36continues moving up where a shifting member on it that is not shown will eventually release the main bore packer40and continued upward movement of the inner string separates the upper portion82from the lower portion84while seal bore44just below the lower portion84will now be exposed to accept leg62of the junction60when delivered in the next trip. The disconnect80, also referred to as38inFIG. 2, transmits torque from upper section82to lower section84using ridges106on the upper section82that mesh into slots108in the lower section84as shown inFIG. 9. The arrangement can be reversed or differently designed to avoid transmission of torque through the dogs86.

Those skilled in the art will appreciate that in a single trip a gravel packing can be accomplished in a lateral without the junction in place so that a larger completion can be run. The main bore packer can then be released from the isolation packer in the lateral with a disconnect so that the inner string can take with it a part of the disconnect to expose a seal bore in the lateral and the main bore packer. The junction can then be run and tagged into seal bores in the main bore and in the lateral for production through the main bore or the lateral or both using a production string tagged into a packer delivered. The method saves an extra step of individually removing the main bore packer by using a disconnect to allow removal of the main bore packer with the inner string that releases not only the disconnect but also the upper packer so they can be removed in tandem.