Patent Publication Number: US-7708076-B2

Title: Method of using a drill in sand control liner

Description:
FIELD OF THE INVENTION 
   The field of the invention is liners that are rotated to drill without a drill string and more particularly where the liners have openings with sand control devices and the openings are unsealed after drilling is complete. 
   BACKGROUND OF THE INVENTION 
   Saving trips into the well saves the well operator money. One such time saving technique that has been developed is running a liner with screens on a drill string so that as the bit advances so does the liner. When the desired location is reached, the drill string up to the bit is released from the bit that is rotatably mounted to the liner. The liner doesn&#39;t rotate as the bit turns. After the drill string is disconnected from the bit and removed, a swage can be run in to expand the screen or an isolation packer and a crossover can be run in and a gravel pack operation can be performed. This technique is illustrated in U.S. Pat. No. 7,108,083. The bit can be driven by a drill string or a downhole motor supported by coiled tubing. 
   Drill strings have been used with screens in the liner when running in liner while drilling the hole because of the need to deliver pressurized drilling mud to the bit nozzles to displace the drill cuttings and cool the bit. Since the screen is an open structure, it has not been practical to deliver liner while making hole without using a drill string inside the liner so that pressurized mud can be directly delivered to the bit while the drill string supports the liner in a manner where the liner doesn&#39;t see fluid pressure in advance of the bit. 
   In trying to eliminate the drill string and rotate a bit with a liner, particularly a liner that has screens or an array of slots, the problem that is confronted is the limited ability of such a structure to tolerate the applied torque from drilling and how to make the structure a conductor of pressurized fluid so that the bit nozzles could be supplied with cooling fluid and a means to get drill cuttings out of the way. Another consideration is to avoid perforation using explosives as it can cause damage to sensitive formations and the perforating guns can become stuck after detonation in low bottom hole pressure wells. The present invention solves these problems by providing a robust liner structure that can withstand the applied torque and drive the bit while still having the capability to convey pressure to the bit nozzles and when drilling is concluded to open passages with sand control features so that production can begin with the liner suspended and sealed to an existing and cemented well tubular. These and other features of the present invention will be more readily apparent from a review of the description of the preferred embodiment and the associated drawing while recognizing that the claims determine the full scope of the invention. 
   SUMMARY OF THE INVENTION 
   A liner rotates a bit to make more hole. The liner has openings with inserts in them to lend torque resistance to the liner. The inserts have a passage with a sand control media in the passage and a seal so that the liner can hold pressure for run in to get proper circulation through the bit. When a sufficient hole is made, the liner is hung off an existing cemented tubular and the seal for the passages within the sand control media is removed by a variety of techniques so that the formation can be produced in a single trip. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
       FIG. 1  is a section view of the tubular making hole with the bit at the bottom and a detailed view of an insert in one of the openings. 
       FIG. 1   a  is an enlarged view of the insert. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  shows a casing  10  that has been cemented in wellbore  12 . Wellbore  12  is drilled with bit  14  secured to liner string  16  in a manner where they rotate in tandem. Near the top  17  of the string  16  is a liner hanger  18  of a type well known in the art. When the wellbore  12  is drilled, the hanger  18  with its slips and seal can be actuated so that the string  16  is supported by the casing  10 . A run in string  20  delivers the liner string  16  through the casing  10  in drilling the hole  12  to drive the bit  14  by virtue of a releasably and rotationally locked latch connection  37  of a type well known in the art. 
   String  16  has an array of holes  22  with internal threads  24  to allow securing insert  26  at its threads in holes  22 . Inserts  26  can be welded into position but a threaded connection is preferred as it is cheaper to assemble and allows fast removal for replacement of any inserts  26  when needed. Each insert  26  has a passage  28  therethrough. Inside passage  28  is a sand control medium  30  that is preferably sintered metal beads compatible with the anticipated well fluids and conditions. Illustratively shown for a single opening but present in all openings  22  is a sealing material  32  so that pressurized drilling mud delivered through run in string  20  is retained in the liner  16  and communicated to bit  14  to allow it to drill. Bit  14  may be releasably mounted to the lower end  34  of the liner  16  and run in string  20  can have a gripping mechanism, shown schematically as  36  at its lower end. The gripping mechanism  36  can grab the bit  14  which can be of a collapsible design so that it can be retrieved back through the liner  16  when drilling is done. Alternatively, the run in string  20  can also include a swage, shown schematically as  38  so that at the conclusion of drilling, the liner  16  can be expanded in the same trip. If the liner is expanded, the bit  14  need not have a collapse feature to be removed through it after expansion. 
   In drilling the wellbore  12 , the run in string  20  and the liner  16  are rotated to turn the bit  14  to make the hole  12 . The sealing material  32  initially plugs the passages  28  so that pressurized drilling mud can be delivered to the bit  14  to carry away cuttings. Drilling continues until the proper depth is reached or until the pressures downhole get so high as to risk fluid loss into the formation and an inability to clear cuttings away from the bit. At that point the sealing material  32  is removed. Depending on what material is selected for sealing, it can be removed in a variety of ways without string rotation. It can be dissolved, chemically attacked or simply designed to go away after prolonged exposure to well fluids or conditions. It can also be removed with a stimulus such as heat applied in the well. The removal, either partial or total of the sealing material  32  allows production to come through the sand control medium  30  and into the liner  16 . The well fluids can go to the surface through a production string and packer that replace the run in string  20  or alternatively, production can be taken through the run in string  20  itself saving another two trips for removing the run in string  20  and replacing it with a production string and packer (not shown). If expansion of the liner string  16  is contemplated, it can be done before the sealing material  32  is removed or after but preferably before production to the surface is allowed to start. If the bit  14  is to be retrieved then it should be done before production begins. The liner string  16  can be set on bottom before production begins or it can have its lower end  34  closed off to flow by other means. 
   Those skilled in the art will appreciate that a liner string  16  is presented that has the strength in torsion to operate a bit  14  and has the capability of selectively retaining pressure during drilling so that fluid can be forced through the bit nozzles while drilling. Perforating the liner for production access is not required in this situation. The sealing devices  32  are made to go away when drilling is concluded to provide access to production in passages  28 . Expansion of the liner  16  is possible in a single trip as is the ultimate capture and retrieval of the bit  14  through the liner  16  regardless of whether the liner is expanded or not. The openings  22  can be threaded in the wall or welded. The interior wall  40  should preferably be smooth with no internal projections if expansion is contemplated. Various known swages and expansion techniques can be used. The number and layout of openings  22  as well as their size can vary depending on the anticipated production rates. 
   The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below.