Drilling Method and Apparatus

Abstract

Apparatus for drilling a borehole from a first subterranean location to a second subterranean location, comprises a casing ( 4 ) extending longitudinally inside a borehole, a conduit ( 6 ) extending longitudinally inside casing ( 4 ), and capable of being in sealing relationship therewith, at least one entry line ( 23,24 ) for liquid into the apparatus, a first annulus ( 22 ) between the casing ( 4 ) and conduit ( 6 ), at least one entry for liquid in the conduit, a tubing ( 14 ) having a first end and a second end ( 16 ), a remote controlled electrically powered drilling device ( 12 ) and remote controlled electrically powered pump, the device and pump being capable of being in fluid contact with the first end of the tubing ( 14 ), the second end ( 16 ) of the tubing ( 14 ) being inside the conduit ( 6 ) at a location more remote from the drilling device ( 12 ) than the entry for liquid in the conduit ( 6 ), with the conduit ( 6 ), tubing ( 14 ) and first end and second end ( 16 ) of the tubing ( 14 ) being adapted to provide routes for liquid contact between conduit ( 6 ) and drilling device ( 12 ), the routes being respectively internally and externally of the tubing ( 14 ).

1 . Method of drilling a borehole from a first subterraneous location to a second subterranean location, which method comprises
 (i) passing liquid into an apparatus in at least one location, said apparatus comprising a casing ( 4 ) extending longitudinally inside a borehole, a conduit ( 6 ) extending longitudinally inside said casing, and capable of being in sealing relationship therewith, a first annulus ( 22 ) between said casing and said conduit, entry for said liquid in said conduit, tubing ( 14 ) having a first end present in said first location and a second end ( 16 ) present inside said conduit above said entry for liquid in said conduit, a remote controlled electrically powered drilling device ( 12 ) located in said first subterranean location and a remote controlled electrically powered pump;   (ii) passing a first stream of said liquid into said conduit below said second end;   (iii) passing a second stream of said liquid from inside the casing to said drilling device in said first location;   (iv) drilling said borehole in the present of said liquid to produce a slurry of drill cuttings in said liquid;   (v) passing said slurry along said tubing from said first end to said second end where said slurry is emitted into said first stream of said liquid moving upwardly in said conduit from said entry.   
   
   
       2 . A method according to  claim 1 , wherein the liquid enters the apparatus at a non-subterranean location. 
   
   
       3 . A method according to  claim 1 , wherein the liquid passes into said first annulus and at least a part thereof passes into said conduit. 
   
   
       4 . A method according to  claim 3 , wherein substantially all the liquid passes through the wall of the conduit. 
   
   
       5 . A method according to  claim 4 , wherein the liquid passes into the conduit via at least one perforation or slot ( 21 ) in its wall. 
   
   
       6 . A method according to  claim 5 , wherein the wall of the conduit ( 6 ) has a first perforation or slot ( 21 ) through which the liquid passes and at least one further perforation or slot located more remote from said drilling device than said first perforation or slot, each further perforation or slot being sealed but capable of being unsealed. 
   
   
       7 . A method according to  claim 4 , wherein the liquid passes into the conduit via a slot in its wall, which slot is reversibly covered with a sliding sleeve. 
   
   
       8 . A method according to  claim 3 , wherein the liquid divides into 2 streams, one passing up the conduit and the other passing towards the drill device. 
   
   
       9 . A method according to  claim 3 , wherein the liquid passes through the first annulus to the bottom of the conduit, and divides into a first stream and a second stream, said first stream passing into the conduit to the second end of the tubing and said second stream passing around said tubing outside the conduit and to said drill device. 
   
   
       10 . A method according to  claim 1 , wherein said liquid flows directly into said conduit, without access of said liquid into said annulus. 
   
   
       11 . A method according to  claim 1 , wherein said borehole being drilled is a lateral or side track borehole from a main borehole. 
   
   
       12 . A method according to  claim 11 , wherein the lateral or sidetrack borehole is in an oil bearing formation and the main borehole is a producing well. 
   
   
       13 . A method according to  claim 11 , wherein the lateral or sidetrack borehole is in a water formation and the main borehole is a water injection well. 
   
   
       14 . A method according to  claim 1 , wherein the borehole is drilled into a formation barren of water or oil. 
   
   
       15 . A method of producing hydrocarbons from a lateral or sidetrack well in a subterranean oil bearing formation, which has been at least partly drilled by a method according to  claim 6 , wherein the flow of aqueous liquid is stopped, said other perforations or slots in said conduit are unsealed and gas is passed down said annulus through at least some of the perforation or slot and other perforations or slots in a gas lift operation to aid movement of oil from said formation into said well and hence into said conduit. 
   
   
       16 . Apparatus for drilling a borehole from a first subterranean location to a second subterranean location, which apparatus comprises a casing ( 4 ) extending longitudinally inside a borehole, a conduit ( 6 ) extending longitudinally inside said casing, and capable of being in sealing relationship therewith, at least one entry line ( 23 , 24 ) for liquid into said apparatus, a first annulus ( 22 ) between said casing ( 4 ) and said conduit ( 6 ), at least one entry for liquid in said conduit, a tubing ( 14 ) having a first end and a second end ( 16 ), a remote controlled electrically powered drilling device ( 12 ) and a remote controlled electrically powered pump, said drilling device and pump being capable of being in fluid contact with said first end of said tubing ( 14 ), said second end ( 16 ) of said tubing ( 14 ) being inside said conduit ( 6 ) at a location more remote from said drilling device ( 12 ) than said entry for liquid in said conduit ( 6 ), wherein tubing ( 14 ) and first end and second end ( 16 ) thereof are adapted to provide two routes for liquid contact between said conduit ( 6 ) and said drilling device ( 12 ), said routes being respectively internally and externally of said tubing ( 14 ). 
   
   
       17 . Apparatus according  claim 16 , wherein the entry line ( 23 ) for liquid is into said first annulus ( 22 ), and said conduit ( 6 ) and said first annulus ( 22 ) are capable of being in liquid contact. 
   
   
       18 . Apparatus according to  claim 17 , wherein the first annulus ( 22 ) comprises a packer ( 7 ) sealing it from liquid flow there through, and liquid contact between said conduit ( 6 ) and said first annulus ( 22 ) is through the wall of said conduit. 
   
   
       19 . Apparatus according to  claim 18 , wherein said liquid contact is via at least one perforation or slot ( 21 ) in said wall of said conduit. 
   
   
       20 . Apparatus according to  claim 19 , wherein said wall has a first perforation or slot ( 21 ) opened to provide said liquid entry and at least one further perforation or slot located more remote from said drilling device than said first perforation or slot ( 21 ) and each further perforation or slot are sealed but capable of being unsealed. 
   
   
       21 . Apparatus according to  claim 18 , wherein said conduit ( 6 ) wall has a slot therein reversibly covered with a sliding sleeve capable of allowing or denying liquid contact through said wall of said conduit. 
   
   
       22 . Apparatus according to  claim 16 , wherein said first annulus ( 22 ) and said conduit ( 6 ) are capable of being in liquid contact past the lower end of said conduit. 
   
   
       23 . Apparatus according to  claim 16 , wherein said entry of liquid is a tube ( 25 , 26 ) entering said conduit ( 6 ) directly without access of said liquid to said first annulus ( 22 ).