METHOD OF INSTALLING TUBING INTO A LATERAL BOREHOLE

Abstract: A method of installing tubing (2) into a lateral borehole (4) which extends from a primary borehole (6), wherein the primary borehole is provided, at a point below the intersection of the primary and laterally boreholes, with a support device (8), comprises: running into the primary borehole a deflector device (10) until the deflector device is engaged with the support device with the deflector face (12) of the deflector device orientated to deflect tubing into the lateral borehole; surrounding the upper portion of the deflector device with an elongate tubular member (14) having a pre-formed window (16) in register with the mouth of the lateral borehole; sealing between the elongate tubular member and the casing (18) of the primary borehole at a location above the intersection between the primary borehole and the lateral borehole; and running a length of tubing through the elongate tubular member to be deflected by the deflector device through the pre-formed window into the lateral borehole.

Description: METHOD OF INSTALLING TUBING INTO A LATERAL BOREHOLE This invention provides improvements in and relating to the completion of laterals or branch boreholes. Our patent application 9614976.0 describes certain techniques for the formation and lining of branch boreholes or laterals. The present invention relates to improvements in these techniques According to one aspect of the present invention a method of installing tubing 2 into a lateral borehole 4 which extends from a primary borehole 6, wherein the primary borehole 6 is provided, at a point below the intersection of the primary and laterally boreholes, with a support device 8, comprises, running into the pπmary borehole 6 a deflector device 10 until the deflector device 10 is engaged with the support device 8 with the deflector face 12 of the deflector device orientated to deflect tubing 2 into the lateral borehole 4, surrounding the upper portion of the deflector device 10 with an elongate tubular member 14 having a pre-formed window 16 in register with the mouth of the lateral borehole 4, sealing between the elongate tubular member 14 and the casing 18 of the primary borehole at a location above the intersection between the primary borehole and the lateral borehole; and running a length of tubing 2 through the elongate tubular member 14 to be deflected by the deflector device 10 through the pre-formed window 16 into the lateral borehole 4. According to the preferred embodiment of the present invention a branch borehole is formed, lined and completed by the following sequence of steps: 1 Prepare well for setting packer and whipstock, typically carry out a drift and scraper run. 2 Run in hole, orient and set packer, in this application the packer should have a maximum ID for communication to the lower well bore, as various assemblies will be located in the packer bore from time to time, and during production a restriction may be left in the packer bore. RECTIFIED SHEET ( RULE 91 ) - 1 a - Check orientation of riser slot in the packer to confirm if desired. Make up and orient whipstock to anchor latch assembly, include RECTIFIED SHEET (RULE 91 ) - 2 - debris barrier between whip and anchor latch to catch junk (cuttings etc). Note that the whipstock and assembly is to be recovered, therefore the assembly is retrievable by means such as an overshot, die collar, special retrieving tool on whip face or other such means. Run in hole on the starter mill (or running tool) and latch into packer Check engagement, shear off starter mill (or running tool) and mill cut out in the casing The window milling assembly could belong to a single trip system where the window is milled in one continuous run, excluding a definitive starter mill run. Pull out of hole, lay down starter milling assembly and pick up window milling assembly Run in hole and mill the window including a rat hole in the formation Pull out of hole Lay down milling assembly. Pick up retrieving tool, run in hole and recover the whipstock, debris barrier and anchor latch assembly. Lay equipment out on surface. Check the direction of the window by comparative means assessing the wear pattern on the whip face Record any offset relative to the lug on the anchor latch assembly as this will affect the orientation of the deflector face to the anchor latch relative to the window just milled. Make up the deflector assembly 10', typically consisting of an anchor latch, debris barrier, centraliser and telltale, and deflector The space out of the deflector will be such that it will be just below the bottom of the maximum opening of the window which is calculated to allow the maximum OD liner out through the window without fouling the formation. A special milling assembly will be run to ream the window to allow the drilling assembly through. Run in hole on running tool or special milling assembly. Latch into packer bore and release running tool or milling assembly. If milling assembly in hole, ream through the window and open casing and formation, if running tool, pull out and change for milling/reaming assembly. The pilot or taper mill must be under gauge to pass through the window and have a stinger to allow it to enter the rat hole whilst RECTIFIED SHEET ( RULE 91 ) - 3 - guiding the reamer (watermelon mill) through, and not make a new hole in the formation Pull assembly out of hole, lay down Make up drilling assembly and drill well to depth, (TD) Pull out of hole circulating well clean Run liner into hole leaving a centralised protrusion of the liner in the well bore and cement into place displacing cement up through the annulus and across the junction to seal the window around the liner Pick up washover assembly, including integral stabilised washpipe and run in hole, wash down over the liner protruding into the well bore (which is a smaller OD than the ID of the well bore casing) and slice it off, at the same time removing any surplus cement from the ID of the casing If the liner is protruding too high in the well bore as a result of not being able to get it to depth, it may be necessary to mill it down to an acceptable depth for washing over Continue washing over till the liner is cut, and if possible down over the deflector and centraliser The cut off piece of the liner may at this point cause a peak in torque preventing wash down to this depth, in which case the washover assembly should be recovered and the liner protrusion recovered using an overshot or spear, (conventional means of recovery) Rerun washover assembly to ensure cement is clear of the deflector assembly Pull out of hole and lay assembly down Recover the deflector assembly, including the anchor latch Clean up the well bore Pick up new deflector assembly 10 which when run will be slightly higher up the well bore 6 in the window 20 when latched into the packer 8 This will allow a smaller OD liner 2 to be run into the new liner 22 which has just been sliced off The deflector 10 will be made up to an anchor latch 24 as previously, but there is no requirement for a debris barrier The deflector 10 will have a through bore 26 and flow ports 28 below the scalloped face 12, the through bore 26 will not interfere with the completion that RECTIFIED SHEET R E 91 is to be deflected off this face 12 The completion may restrict the flow area through the scalloped face 12 thus the need for the ports 28 The lower well bore 30 will be able to communicate with the upper well bore 32 through the deflector The deflector 10 will have a means 34 of locating and sealing a piece of casing 36 which will extend from it upwardly in the well bore 6 and which shall be attached to the bottom of another big bore packer 38, effectively creating a sealed element across the iateral junction In addition the piece of casing 36 will have a pre-formed window 16 cut into it which when placed in the assembly will locate adjacent to the window 20 and iateral well bore 4 with the liner 22 in place The upper big bore packer 38 will be located in sound casing above the window 20 to effect the aforementioned seal Effectively the assembly will be tied in length and orientation relative to the lower big bore packer 8 and liner 22 in the window By way of example, the original window 20 could be cut in 9VB" casing 18, an BVY hole drilled, a 7" liner 22 run, upper packer 38 with 8Vβ" casing 36 and pre-cut window 16 latched into lower packer 8 and set, a 4>2" or 5" tubing completion 2 run and set in the upper packer 38 with a sliding sleeve side door 40 set within the δ'/β" casing 36, extending through into the 7" liner 22 with another packer and seal assembly to isolate it in the 7" liner The SSSD 40 would then be closed to allow production from the 7" liner 22 through the AVz" or 5" completion 2, but being isolated from the lower well bore 30, and when the SSSD is opened production or communication from the lower well bore in addition to the Iateral and therefore co-mingling of the produced zones Pick up new deflector assembly 10, ensuring desired space out is achieved Make up to casing 36 with pre-cut window 16, check orientation and lock, ensure seal 34 is in place Make up to upper big bore packer 38 Run in hole and latch into lower packer 8, set upper RECTIFIED SHEET (RULE 91 ) - 5 - packer 38. Pull running-assembly out of hole, lay down Run and set packer in 7" liner, (deflecting off deflector through pre-cut window) Make up completion, (AVz ' or 5") with SSSD placed such that it is preferably above the deflector sub 10 Run in hole and set in top packer, this point being sealed as well, the completion will extend through the packer and seal assembly in the 7" having also been deflected into the 7" liner. RECTIFIED SHEET ( RULE 91 )

Claims: - 6 CLAIMS 1 A method of installing tubing into a Iateral borehole which extends from a pπmary borehole, wherein the primary borehole is provided, at a point below the intersection of the pπmary and laterally boreholes, with a support device, the method comprising running into the primary borehole a deflector device until the deflector device is engaged with the support device with the deflector face of the deflector device orientated to deflect tubing into the Iateral borehole; surrounding the upper portion of the deflector device with an elongate tubular member having a pre-formed window in register with the mouth of the Iateral borehole, sealing between the elongate tubular member and the casing of the pπmary borehole at a location above the intersection between the primary borehole and the Iateral borehole, and running a length of tubing through the elongate tubular member to be deflected by the deflector device through the preformed window into the Iateral borehole 2. A method according to claim 1 wherein the deflector device and the elongate tubular member are pre-assembled and run into the well together 3 A method according to claim 1 or claim 2 wherein there is a sliding seal between the deflector device and the elongate tubular member 4 A method according to any preceeding claim wherein the tubing run into the Iateral borehole includes a valve to permit selective communication between the interior of the tubing and the interior of the elongate tubular member 5 A method according to claim 4 wherein thge valve is a sliding sleeve side door 6 A method according to any preceding claim wherein the deflecting device includes through passages which provide communication between the portion of RECTIFIED SHEET (RULE 91 ) the primary borehole located below the support device to the interior of the elongate tubular member. 7. A method according to any preceding claim wherein a seal is established between the deflector device and the casing of the primary borehole below the location of the intersection of the primary and Iateral boreholes. 8. A method according to any preceding claim wherein the elongate tubular member is secured to the casing of the primary borehole above the location of the intersection RECTIFIED SHEET (RULE 91 )

Inventors: BRUCE RONALD JAMES, MCGARIAN BRUCE, BRUCE, RONALD, JAMES, MCGARIAN, BRUCE
Applicants: BRUCE RONALD JAMES, MCGARIAN BRUCE, SMITH INTERNATIONAL, BRUCE, RONALD, JAMES, MCGARIAN, BRUCE, SMITH INTERNATIONAL, INC.
Application year: 1997
Main classification: E21B43
IPC codes: E21B41, E21B43