Accelerated start-up in sagd operations

Abstract

A method of initiating or accelerating the establishment of fluid communication between horizontal wells located in a formation of very limited fluid mobility, such as an oil sand at original temperature or an infill well completed in an immobile hydrocarbon region located between surrounding well patterns in which a gravity-dominated recovery process is or has been operated.

1 . A method wherein a selected amount of solvent is injected at sub-fracturing conditions (pressure or rate or both) and ambient temperature into a first horizontal well located in an immobile formation or reservoir, so as to accelerate fluid communication in the formation or reservoir between the first horizontal well and a second horizontal well with which the first horizontal well is not in fluid communication. 
     
     
         2 . The method of  claim 1 , wherein the solvent is xylene, benzene, toluene, phenol or mixtures or derivatives thereof. 
     
     
         3 . The method of  claim 1 , wherein the solvent is injected into either the first horizontal well or the second horizontal well, or into both the first horizontal well and the second horizontal well. 
     
     
         4 . The method of  claim 1 , wherein the immobile formation or reservoir is an oil sand reservoir at original conditions. 
     
     
         5 . The method of  claim 4 , wherein the original conditions includes a bitumen or heavy oil density of about 12° API or heavier. 
     
     
         6 . The method of  claim 5 , wherein the bitumen or heavy oil density is about 15° API or heavier. 
     
     
         7 . The method of  claim 1 , wherein the selected amount of solvent is a volume less than ten times the volume of the first horizontal well completion. 
     
     
         8 . The method of  claim 1 , wherein a further selected amount of solvent is injected at sub-fracturing conditions and ambient temperature into the second horizontal well. 
     
     
         9 . The method of  claim 8 , wherein the further selected amount of solvent is a volume less than ten times the volume of the second horizontal well completion. 
     
     
         10 . The method of  claim 8 , wherein the total of the selected amount of solvent and the further selected amount of solvent is a volume less than ten times the volume of the total of the first horizontal well completion and the second horizontal well completion. 
     
     
         11 . The method of  claim 1 , wherein the solvent is displaced into the immobile formation or reservoir using a displacing fluid sufficient to displace substantially all of the selected volume of solvent into the formation or reservoir. 
     
     
         12 . The method of  claim 11 , wherein the displacing fluid is a non-condensing, non-oxidizing gas. 
     
     
         13 . The method of  claim 12 , wherein the displacing fluid is substantially nitrogen. 
     
     
         14 . The method of  claim 1  wherein the injected solvent is allowed to remain resident in the immobile formation or reservoir for a selected period of time before a subsequent recovery process is implemented. 
     
     
         15 . The method of  claim 14 , wherein the solvent is displaced into the immobile formation or reservoir using a displacing fluid sufficient to displace substantially all of the selected volume of solvent into the formation or reservoir after the selected period of time before the subsequent recovery process is implemented. 
     
     
         16 . The method of  claim 1  whereby, following application of the method to establish inter-well communication, a subsequent recovery process is implemented. 
     
     
         17 . The method of  claim 16 , wherein the subsequent recovery process is SAGD or other gravity-dominated recovery processes that involved the use of solvents, either thermally or non-thermally. 
     
     
         18 . The method of  claim 1  wherein the first horizontal well is an infill well that is completed in an immobile hydrocarbon region located between surrounding well patterns of a gravity-dominated recovery process. 
     
     
         19 . The method of  claim 18  wherein the immobile hydrocarbon region is in a bypassed region, remaining between adjacent mobilized hydrocarbon regions of a gravity-dominated recovery process. 
     
     
         20 . The method of  claim 18  wherein fluid communication is established between the first horizontal well and an adjacent mobilized hydrocarbon region of a gravity-dominated recovery process. 
     
     
         21 . The method of  claim 18  wherein fluid communication is established between the first horizontal well and an adjacent common mobilized hydrocarbon region of a gravity-dominated recovery process.