Methods For Containment and Improved Recovery in Heated Hydrocarbon Containing Formations By Optimal Placement of Fractures and Production Wells

Abstract

A method for containing and capturing liquids and gases generated during in situ pyrolysis that migrate through pyrolysis generated or natural fractures includes placing a row of horizontal hydraulic fractures above and below the heated zone and completing production wells within the horizontal hydraulic fractures. The method serves at least two purposes: 1) provides a local zone of weak mechanical strength to blunt the propagation of vertical pyrolysis generated fractures and 2) provides a drainage point for fluids to relieve pressure in the formation and improve recovery. Preferably, the organic-rich rock formation is an oil shale formation.

What is claimed is: 
     
         1 . A method for producing hydrocarbon fluids from an organic-rich rock formation, comprising:
 completing at least one heater well in a heated zone in the organic-rich rock formation;   completing a production well;   heating the heated zone of the organic-rich rock formation from the at least one heater well, thereby pyrolyzing at least a portion of the organic-rich rock into hydrocarbon fluids and thereby creating thermal fractures in the organic-rich rock formation due to thermal stresses created by heating;   placing a barrier to decrease the propagation of the thermal fractures wherein placing the barrier comprises placing hydraulic horizontal fractures above and/or below the heated zone from the production well; and   producing hydrocarbon fluids from the production well.   
     
     
         2 . The method of  claim 1 , wherein the organic-rich rock formation is an oil shale formation. 
     
     
         3 . The method of  claim 2 , wherein the thermal fractures are substantially vertical. 
     
     
         4 . The method of  claim 2 , further comprising:
 performing geomechanical modeling to determine the direction and extent of thermal fractures.   
     
     
         5 . The method of  claim 2 , wherein the step of hydraulically fracturing is performed before the step of heating the oil shale formation. 
     
     
         6 . The method of  claim 2 , wherein the step of hydraulically fracturing is performed after the step of heating the oil shale formation has begun, but before the substantial formation of thermal fractures. 
     
     
         7 . The method of  claim 2 , further comprising:
 determining a distance from the production well in which to form the one or more hydraulic fractures in order to provide fluid communication with anticipated thermal fractures.   
     
     
         8 . The method of  claim 2 , wherein the thermal fractures intersect at least one of the hydraulically fractures within one year of initiating heating. 
     
     
         9 . The method of  claim 2  wherein the step of heating results in at least a portion of the oil shale formation reaching a temperature of 270° C. or greater. 
     
     
         10 . The method of  claim 2 , further comprising introducing a proppant material into one or more of the hydraulic fractures. 
     
     
         11 . The method of  claim 2 , wherein the hydraulic fractures are placed in the organic-rich rock formation. 
     
     
         12 . The method of  claim 2 , wherein the hydraulic fractures are placed in a formation above or below the organic-rich rock formation. 
     
     
         13 . The method of  claim 2 , wherein the production well is horizontal.