Method of drilling from a shaft for underground recovery of hydrocarbons

Abstract

The present invention discloses a selection process for installing underground workspace in or near a hydrocarbon deposit that is an appropriate workspace from which to drill, operate and service wells applicable to any of a number of methods of recovering hydrocarbons. The present invention includes a number of innovative methods for developing workspace for drilling from a shaft installed above, into or below a hydrocarbon deposit, particularly when the hydrocarbon reservoir is at significant formation pressure or has fluids (water oil or gases) that can enter the workspace. These methods can also be used for developing workspace for drilling from a tunnel installed above, into or below a hydrocarbon deposit. The present invention also discloses a procedure for evaluating the geology in and around the reservoir and using this information to select the most appropriate method of developing workspace for drilling from a shaft and/or tunnel.

1 . An excavation method, comprising:
 (a) providing a substantially vertically inclined shaft, at least a portion of the substantially vertically inclined shaft being lined to inhibit entry, into an interior of the at least a portion of the substantially vertically inclined shaft, of a formation fluid from a hydrocarbon-containing formation;   (b) at a selected level of the at least a portion of the substantially vertically inclined shaft, forming, while maintaining a pressure and fluid seal between the shaft interior and the formation, a plurality of recess cavities extending approximately radially outward from the at least a portion of the substantially vertically inclined shaft, the selected level being adjacent to or near a hydrocarbon-containing formation; and   (c) drilling, while maintaining a pressure and fluid seal between the at least a portion of the substantially vertically inclined shaft interior and the formation to inhibit entry of the formation fluid into the shaft interior, at least one well outward from a face of each of the recess cavities, the at least one well penetrating at least a portion of the hydrocarbon-containing formation and wherein the seal is maintained continuously during the duration of formation and operation of the at least one well.   
     
     
         2 .- 3 . (canceled) 
     
     
         4 . The method of  claim 1 , wherein the drilling step (c) comprises:
 (c1) from the at least a portion of the substantially vertically inclined shaft, drilling through a flange positioned adjacent to a surface of the at least a portion of the substantially vertically inclined shaft to form a drilled hole extending outwardly from the at least a portion of the substantially vertically inclined shaft;   (c2) placing a cylindrical shield in the drilled hole;   (c3) securing the shield to the surface of the at least a portion of the substantially vertically inclined shaft; and   (c4) introducing a cementitious material into, an end of the drilled hole to form a selected recess cavity, wherein, when the cementitious material sets, the set cementitious material and shield will seal the interior of the cavity from formation fluid.   
     
     
         5 . The method of  claim 1 , wherein the drilling step (c) comprises:
 (c1) from the at least a portion of the substantially vertically inclined shaft, drilling, by a drill stem and bit, through a flange and sealing gasket, the flange and gasket being positioned on a surface of the at least a portion of the substantially vertically inclined shaft, to form a drilled hole extending into the hydrocarbon-containing formation;   (c2) while the hole is being drilled extending a cylindrical shield into the hole in spatial proximity to the drill bit, the shield surrounding the drill stem;   (c3) pumping a cementitious composition through the drill stem and into a bottom of the drilled hole;   (c4) securing the shield to the flange; and   (c5) after the cementitious composition has set, removing the drill stem from the hole to form a selected recess cavity, wherein, when the cementitious material sets, the set cementitious material and shield will seal the interior of the cavity from formation fluid.   
     
     
         6 . The method of  claim 1 , wherein the forming step comprises:
 stabilizing the hydrocarbon-containing formation by ground freezing and/or soil mixing;   while the formation is stabilized, drilling the recess cavity into the formation; and   installing a liner to seal the recess cavity interior from the formation.   
     
     
         7 . (canceled) 
     
     
         8 . The drilling method of  claim 1 , wherein the drilling step (c) comprises:
 (C1) from the at least a portion of the substantially vertically inclined shaft, drilling through a flange positioned adjacent to a lined surface of a selected recess to form a drilled hole extending outwardly from the at least a portion of the substantially vertically inclined shaft;   (C2) placing a cylindrical shield in the drilled hole;   (C3) securing the shield to the lined surface of the excavation; and   (C4) introducing a cementitious material into an end of the drilled hole to form a selected recess cavity, wherein, when the cementitious material sets, the set cementitious material and shield will seal the interior of the hole from formation fluid of the hydrocarbon-containing formation.   
     
     
         9 . The method of  claim 8 , wherein, in the drilling step (C1), a drill stem and attached bit, drill through a flange and the sealing gasket, the flange and gasket being positioned on the at least a portion of the substantially vertically inclined shaft surface and wherein the drilled hole extends into a hydrocarbon-containing formation. 
     
     
         10 . The method of  claim 8 , wherein, during the drilling step, (a) a cylindrical shield is extended into the hole in spatial proximity to the drill bit, the shield surrounding the drill stem. 
     
     
         11 . The method of  claim 10 , wherein the shield rotates in response to rotation of the bit. 
     
     
         12 .- 24 . (canceled) 
     
     
         25 . An excavation method, comprising:
 (a) providing a substantially vertically inclined shaft, at least a portion of the substantially vertically inclined shaft being lined to inhibit entry, into an interior of the at least a portion of the substantially vertically inclined shaft, of a formation fluid from a hydrocarbon-containing formation;   (b) at a selected level of the at least a portion of the substantially vertically inclined shaft, forming, while maintaining a pressure and fluid seal between the at least a portion of the substantially vertically inclined shaft interior and the formation, a plurality of recess cavities extending approximately radially outward from the at least a portion of the substantially vertically inclined shaft, the selected level of the at least a portion of the substantially vertically inclined shaft being adjacent to or near a hydrocarbon-containing formation, wherein each of the recess cavities has a diameter ranging from about 1 to about 2 meters and a length ranging from about 4 to about 10 meters; and   (c) drilling, while maintaining a pressure and fluid seal between the at least a portion of the substantially vertically inclined shaft interior and the formation to inhibit entry of formation fluid into the shaft interior, at least one well outward from a face of each of the recess cavities, the at least one well penetrating at least a portion of the hydrocarbon-containing formation and wherein the formation fluid seal is maintained continuously during the duration of formation and operation of the at least one well.   
     
     
         26 . The method of  claim 25 , wherein the recess cavities are lined with a formation fluid impervious liner, wherein the at least a portion of the substantially vertically inclined shaft comprises one or more spaced apart levels, and wherein each of the one or more spaced apart levels comprises a plurality of approximately radially outwardly extending recess cavities.