Methods and systems for drilling from underground access tunnels to develop subterranean hydrocarbon reservoirs

Abstract

A method for accessing a hydrocarbon reservoir in a subterranean formation from a subterranean tunnel system includes (a) drilling a first bore between an upper tunnel and a lower tunnel. In addition, the method includes (b) drilling a second bore downward from the lower tunnel.

What is claimed is: 
     
         1 . A method for accessing a hydrocarbon reservoir in a subterranean formation from a subterranean tunnel system including an upper tunnel and a lower tunnel, the method comprising:
 (a) drilling a first bore between the upper tunnel and the lower tunnel; and   (b) drilling a second bore downward from the lower tunnel.   
     
     
         2 . The method of  claim 1 , further comprising:
 (c) drilling a third bore downward from the second bore.   
     
     
         3 . The method of  claim 2 , further comprising:
 performing (a) and (b) at a first location in the lower tunnel with a first drilling rig; and   performing (c) at a first location in the upper tunnel with a second drilling rig.   
     
     
         4 . The method of  claim 3 , wherein the first drilling rig is disposed in the lower tunnel and the second drilling rig is disposed in the upper tunnel. 
     
     
         5 . The method of  claim 4 , wherein (c) comprises:
 lowering a drill string from the second rig through the first bore and the second bore.   
     
     
         6 . The method of  claim 5 , further comprising:
 installing casing in the first bore with the first drilling rig;   installing casing in the second bore with the first drilling rig; and   installing casing in the third bore with the second drilling rig.   
     
     
         7 . The method of  claim 6 , wherein the drill string forms the casing in the third bore. 
     
     
         8 . The method of  claim 2 , further comprising:
 lowering a first segment of coiled tubing from a coiled tubing drilling rig in the upper tunnel through the first bore, the second bore, and the third bore.   
     
     
         9 . The method of  claim 8 , further comprising drilling with the first segment of coiled tubing to the hydrocarbon reservoir. 
     
     
         10 . The method of  claim 8 , further comprising lowering a second segment of coiled tubing from a service rig in the upper tunnel through the first bore, the second bore, the third bore, and the first segment of coiled tubing. 
     
     
         11 . The method of  claim 3 , further comprising:
 moving the first drilling rig to a second location in the lower tunnel;   performing (a) and (b) at the second location in the lower tunnel with the first drilling rig;   moving the second drilling rig to a second location in the upper tunnel;   performing (c) at the second location in the upper tunnel with the second drilling rig.   
     
     
         12 . A method for accessing a hydrocarbon reservoir in a subterranean formation from a subterranean tunnel system including an upper tunnel and a lower tunnel, the method comprising:
 (a) drilling a plurality of vertical first bores from the lower tunnel to the upper tunnel with a first drilling rig disposed in the lower tunnel;   (b) drilling a plurality of second bores downward from the lower tunnel with the first drilling rig;   (c) drilling a plurality of third bores with a second drilling rig disposed in the upper tunnel, wherein each third bore extends downward from one of the second bores;   (d) installing casing in each of the first bores with the first drilling rig;   (e) installing casing in each of the second bores with the first drilling rig; and   (f) installing casing in each of the third bores with the second drilling rig.   
     
     
         13 . The method of  claim 12 , further comprising:
 drilling a plurality of fourth bores with a third drilling rig disposed in the upper tunnel, wherein each fourth bore extends downward from one of the third bores;   installing casing in each of the fourth bores with the third drilling rig.   
     
     
         14 . The method of  claim 13 , further comprising:
 drilling a plurality of fifth bores with a fourth drilling rig disposed in the upper tunnel, wherein each of the fifth bores extends downward from one of the fourth bores;   installing a liner in each of the fifth bores with the fourth drilling rig.   
     
     
         15 . The method of  claim 14 , wherein the fourth drilling rig is a coiled tubing drilling unit. 
     
     
         16 . The method of  claim 14 , wherein the liner extends into the hydrocarbon reservoir. 
     
     
         17 . The method of  claim 14 , further comprising:
 injecting coiled tubing from the upper tunnel through one of the first bores, one of the second bores, one of the third bores, and one of the fourth bores.   
     
     
         18 . A system for accessing a hydrocarbon reservoir in a subterranean formation, the system comprising:
 an upper tunnel extending through the formation;   a lower tunnel extending through the formation below a portion of the upper tunnel;   a first drilling rig disposed in the lower tunnel and configured to drill a first bore from the lower tunnel to the upper tunnel and drill a second bore downward from the lower tunnel; and   a second drilling rig disposed in the upper tunnel and configured to drill a third bore downward from the second bore.   
     
     
         19 . The system of  claim 18 , wherein the first drilling rig is configured to install tubular casing in the first bore and the second bore; and
 wherein the second drilling rig is configured to install tubular casing in the third bore.   
     
     
         20 . The system of  claim 19 , further comprising a control system at the surface, wherein the control system is configured to remotely operate the first drilling rig or the second drilling rig. 
     
     
         21 . The system of  claim 20 , wherein first drilling rig is disposed on a rail car moveably coupled to a track in the lower tunnel; and
 wherein the second drilling rig is disposed on a rail car moveably coupled to a track in the upper tunnel.   
     
     
         22 . The system of  claim 18 , further comprising:
 a third drilling rig disposed in the upper tunnel and configured to drill through the second bore and the third bore with coiled tubing.