Method and apparatus for casing and directional drilling using bi-centered bit

Abstract

In one aspect, the present invention provides an apparatus to drill a borehole with a casing string. The casing string has affixed thereto a directional drilling assembly and a bi-centered cutter assembly. The bi-centered cutter assembly has a first cutting surface and a second cutting surface that are spaced apart by an offset. The bi-centered cutter assembly is configured to drill the borehole at a gauge diameter.

1 . An apparatus to drill a borehole with a drillstring, the drillstring having an internal bore and an external diameter, the apparatus comprising: 
 the drillstring having a directional drilling assembly connected at a distal end;    said directional drilling assembly having a rotary steerable system, a mud motor, and a bi-centered cutter assembly;    said bi-centered cutter assembly having a first cutting surface and a second cutting surface, wherein said first and said second cutting surfaces are spaced apart by an offset; and    said bi-centered cutter assembly configured to drill the borehole at a gauge diameter.    
   
   
       2 . The apparatus of  claim 1  wherein the drillstring is a casing string, said casing string having a inner casing diameter and an outer casing diameter.  
   
   
       3 . The apparatus of  claim 2  wherein said casing string has a casing latch installed at said distal end between said casing string and said directional drilling assembly, said casing latch having a pass-through diameter smaller than said inner casing diameter.  
   
   
       4 . The apparatus of  claim 3  wherein said bi-centered cutter assembly is configured to be retrieved through said pass-through diameter of said casing latch.  
   
   
       5 . The apparatus of  claim 4  wherein said gauge diameter is larger than said pass-through diameter.  
   
   
       6 . The apparatus of  claim 1  wherein said directional drilling assembly further has directional measurement equipment.  
   
   
       7 . The apparatus of  claim 6  wherein said directional measurement equipment is selected from the group consisting of measurement while drilling tools, accelerometers, magnetometers, and gyroscopes.  
   
   
       8 . The apparatus of  claim 1  wherein the mud motor is a positive displacement mud motor.  
   
   
       9 . The apparatus of  claim 1  wherein the mud motor is a turbine mud motor.  
   
   
       10 . The apparatus of  claim 1  wherein said rotary steerable system and said mud motor are contained within a single housing.  
   
   
       11 . The apparatus of  claim 1  wherein said rotary steerable system is a push the bit rotary steerable system.  
   
   
       12 . The apparatus of  claim 11  wherein said rotary steerable system has at least one synchronous and sequentially actuated peripheral pad to press against the borehole and push the bi-centered cutter assembly in a desired direction.  
   
   
       13 . The apparatus of  claim 11  wherein said rotary steerable system has at least one peripheral pad in a non-rotating, sliding sleeve assembly provided to press against the borehole and push the bi-centered cutter assembly in a desired direction.  
   
   
       14 . The apparatus of  claim 1  wherein said rotary steerable system is a point the bit rotary steerable system.  
   
   
       15 . The apparatus of  claim 14  wherein said rotary steerable system has a geostationary angular orientation device to point said bi-centered cutter assembly in a desired direction.  
   
   
       16 . The apparatus of  claim 1  wherein said first cutting surface is a standard drill bit located on a central axis of said directional drilling assembly.  
   
   
       17 . The apparatus of  claim 16  wherein said second cutting surface is located on a peripheral surface of said directional drilling assembly, wherein a center of rotation of said peripheral surface is displaced from said central axis by said offset.  
   
   
       18 . An apparatus to drill a borehole with a casing string, the casing string having an internal diameter and an external diameter, the apparatus comprising: 
 a directional drilling assembly connected at a distal end of the casing string;    a casing latch installed at said distal end between the casing string and said directional drilling assembly, said casing latch having a pass-through diameter smaller than the internal diameter of the casing string;    a bi-centered cutter assembly, wherein said bi-centered cutter assembly is configured to be retrieved through said pass-through diameter of said casing latch;    said bi-centered cutter assembly having a first cutting surface and a second cutting surface, wherein said first and said second cutting surfaces are spaced apart by an offset; and    said bi-centered cutter assembly configured to drill the borehole at a gauge diameter, wherein said gauge diameter is larger than said pass-through diameter of said casing latch.    
   
   
       19 . The apparatus of  claim 18  further comprising a mud motor.  
   
   
       20 . The apparatus of  claim 19  wherein said mud motor is selected from the group consisting of positive displacement mud motors and turbine mud motors.  
   
   
       21 . The apparatus of  claim 18  wherein said directional drilling assembly has directional measurement equipment.  
   
   
       22 . The apparatus of  claim 21  wherein said directional measurement equipment is selected from the group consisting of measurement while drilling tools, accelerometers, magnetometers, and gyroscopes.  
   
   
       23 . The apparatus of  claim 18  wherein said directional drilling assembly has a rotary steerable system.  
   
   
       24 . The apparatus of  claim 23  wherein said rotary steerable system is a push the bit rotary steerable system.  
   
   
       25 . The apparatus of  claim 24  further comprising at least one synchronous and sequentially actuated peripheral pad to press against the borehole and push the bi-centered cutter assembly in a desired direction.  
   
   
       26 . The apparatus of  claim 24  wherein said rotary steerable system has at least one peripheral pad in a non-rotating, sliding sleeve assembly provided to press against the borehole and push the bi-centered cutter assembly in a desired direction.  
   
   
       27 . The apparatus of  claim 23  wherein said rotary steerable system is a point the bit rotary steerable system.  
   
   
       28 . The apparatus of  claim 27  further comprising a geostationary angular orientation device to point said bi-centered cutter assembly in a desired direction.  
   
   
       29 . The apparatus of  claim 18  wherein said first cutting surface is a standard drill bit located on a central axis of said directional drilling assembly.  
   
   
       30 . The apparatus of  claim 29  wherein said second cutting surface is located on a peripheral surface of said directional drilling assembly, wherein a center or rotation of said peripheral surface is displaced from said central axis by said offset.  
   
   
       31 . The apparatus of  claim 30  wherein said first cutting surface is rotated by a mud motor.  
   
   
       32 . A method to drill a borehole with a drillstring, the method comprising: 
 attaching a drilling assembly to a distal end of the drillstring, the drilling assembly having a rotary steerable system and a bi-centered cutter assembly;    rotating and axially loading the casing string and attached bi-centered cutter assembly to drill a first section of the borehole;    orienting the bi-centered cutter assembly with the rotary steerable system;    sliding the drillstring deeper into the borehole as it is drilled.    
   
   
       33 . The method of  claim 32  wherein the rotary steerable system is a push the bit rotary steerable system.  
   
   
       34 . The method of  claim 33  further comprising pressing at least one synchronous and sequentially actuated peripheral pad against the borehole to push the bi-centered cutter assembly to drill a second section of the borehole in a desired direction.  
   
   
       35 . The apparatus of  claim 31  wherein said rotary steerable system has at least one peripheral pad in a non-rotating, sliding sleeve assembly provided to press against the borehole and push the bi-centered cutter assembly in a desired direction.  
   
   
       36 . The method of  claim 32  wherein the rotary steerable system is a point the bit rotary steerable system.  
   
   
       37 . The method of  claim 36  further comprising pointing the bi-centered cutter assembly with a geostationary angular orientation device to drill a second section of the borehole in a desired direction.  
   
   
       38 . The method of  claim 32  wherein the bi-centered cutter assembly has a first cutting surface and a second cutting surface, wherein the first and the second cutting surfaces are spaced apart by an offset.  
   
   
       39 . The method of  claim 38  wherein the first cutting surface is a standard drill bit located on a central axis of the drilling assembly.  
   
   
       40 . The method of  claim 38  wherein the second cutting surface is located on a peripheral surface of the drilling assembly, wherein a center of rotation of the peripheral surface is displaced from a central axis of the drilling assembly by the offset.  
   
   
       41 . The method of  claim 32  wherein the drillstring is a casing string wherein the casing string has a inner diameter and an outer diameter.  
   
   
       42 . The method of  claim 41  further comprising installing a casing latch at the distal end between the casing string and the drilling assembly, the casing latch having a pass-through diameter smaller than the inner diameter of the casing string.  
   
   
       43 . The method of  claim 42  comprising retrieving the bi-centered cutter assembly through the pass-through diameter of the casing latch.  
   
   
       44 . A method to install a casing string into a borehole while drilling, the method including: 
 attaching a drilling assembly to a distal end of the casing string, the drilling assembly releasably connected to the casing string by a casing latch having a pass-through diameter wherein the pass-through diameter is smaller than an inner diameter of the casing string;    connecting a bi-centered cutter assembly to a distal end of the drilling assembly, the bi-centered cutter assembly configured to drill the borehole at a gauge diameter, wherein the gauge diameter is larger than an outer diameter of the casing string;    drilling a first section of the borehole;    sliding the casing string further into the borehole as it is drilled;    releasing the drilling assembly from the casing latch;    retrieving the drilling assembly and the bi-centered cutter assembly through the casing latch and the casing string; and    cementing the casing string in place.    
   
   
       45 . The method of  claim 44  including rotating the bi-centered cutter assembly with a mud motor.  
   
   
       46 . The method of  claim 44  including rotating the casing string, drilling assembly, and attached bi-centered cutter assembly from the surface.  
   
   
       47 . The method of  claim 46  wherein the drilling assembly includes a rotary steerable system.  
   
   
       48 . The method of  claim 47  wherein the rotary steerable system is a push the bit rotary steerable system.  
   
   
       49 . The method of  claim 48  further including pressing at least one synchronous and sequentially actuated peripheral pad against the borehole to push the bi-centered cutter assembly in a desired direction to drill a second section of the borehole.  
   
   
       50 . The apparatus of  claim 48  wherein said rotary steerable system has at least one peripheral pad in a non-rotating, sliding sleeve assembly to press against the borehole and push the bi-centered cutter assembly in a desired direction.  
   
   
       51 . The method of  claim 47  wherein the rotary steerable system is a point the bit rotary steerable system.  
   
   
       52 . The method of  claim 51  further including using a geostationary angular orientation device to point the bi-centered cutter assembly in a desired direction to drill a second section of the borehole.