Horizontal directional drilling in wells

Abstract

A method and apparatus for horizontally drilling in wells utilizing a shoe assembly at the down hole end of upset tubing. The shoe assembly includes a fixed section and a rotatable section suspended below the fixed section. An electric motor and associated batteries and a gyroscope carried on the rotatable section enable an operator on the surface to selectively rotate and position the rotatable section to any desired angular location for drilling a hole in the well casing. After one or more holes have been cut in the casing, a drill assembly can be removed from the upset tubing and be replaced by a high pressure blaster nozzle to bore into the formation zones. The gyroscope enables the operator to accurately position the rotatable section to the same locations at which the holes have been cut. The drill assembly includes an electric motor with an associated battery, flexible drive shaft, and a hole saw.

1 - 25 . (canceled)  
   
   
       26 . Apparatus for drilling in a well, said apparatus comprising a shoe assembly, a hole saw, an electric motor operatively coupled to said hole saw, and a gyroscope, said shoe assembly being adapted to be lowered into a casing of the well and to direct said hole saw in a predetermined direction at a depth at which a hole or holes are to be cut in a casing wall of said well, said shoe assembly having a longitudinal pathway adapted to receive said hole saw therein, and a lateral pathway oriented at an angle relative to, and in fluid communication with, said longitudinal pathway, said lateral pathway being adapted to receive said hole saw from said longitudinal pathway and to direct said hole saw against said casing wall, said gyroscope being adapted to transmit a signal to indicate an angular location of said hole saw within said well casing.  
   
   
       27 . Apparatus according to  claim 26 , said hole saw comprising a hollow cylindrical body having, at a serrated end thereof, a serrated edge comprising a plurality of cutting teeth.  
   
   
       28 . Apparatus according to  claim 26 , said hole saw further comprising a solid base at a proximal end thereof opposite said serrated end.  
   
   
       29 . Apparatus according to  claim 26 , said casing having an inner surface and an outer surface, said cutting teeth at said serrated edge being effective to cut a circular groove in said inner surface of said casing during a drilling operation.  
   
   
       30 . Apparatus according to  claim 29 , said cutting teeth being further effective to cut a coupon out of said well casing during a drilling operation.  
   
   
       31 . Apparatus according to  claim 26 , said shoe assembly further comprising a support body for supporting said hole saw adjacent an angular location at which it is desired to form a hole in said well casing, said gyroscope being fixed relative to said support body, and being adapted to transmit a signal to indicate the angular location of the support body.  
   
   
       32 . Apparatus according to  claim 27 , said hole saw further comprising an arbor extending at least partly forward of said serrated edge of said cylindrical body.