Producing hydrocarbon material from a layer of oil sand

Abstract

A method of producing hydrocarbon material from a layer of oil sand in an earth formation, the layer having a thickness and extending in an extension direction for more than its thickness comprises creating production borehole having a production borehole section extending in a production borehole direction, and a refill borehole having a refill borehole section extending in a refill borehole direction, wherein both the production and refill borehole directions deviate less than 45 degrees from the extension direction; creating a cavity in the layer of oil sand, the cavity being in fluid communication with the production borehole section; extending the cavity by operating fluid jetting means against a wall of the cavity; withdrawing the slurry from the cavity via the production borehole to a processing facility; and injecting refill material into the cavity via the refill borehole section, wherein the refill borehole section extends below the production borehole section.

1 . A method of producing hydrocarbon material from a layer of oil sand located in an earth formation, the layer of oil sand having a thickness and extending in an extension direction for more than its thickness, the method comprising:
 a) creating a borehole arrangement in the earth formation, including a production borehole having a production borehole section extending in a production borehole direction, and a refill borehole having a refill borehole section extending in a refill borehole direction, wherein both the production and the refill borehole directions are deviating less than 45 degrees from the extension direction;   b) creating a cavity in the layer of oil sand, the cavity being in fluid communication with the production borehole section;   c) extending the cavity by operating fluid jetting means to jet a stream of fluid against a wall of the cavity, to obtain a slurry comprising fluid, hydrocarbon material, and sand;
 withdrawing the slurry from the cavity via the production borehole to a processing facility for processing the slurry; and 
   d) injecting refill material into the cavity via the refill borehole section,   wherein the refill borehole section extends below the production borehole section.   
     
     
         2 . The method of  claim 1 , wherein the production borehole is a combined injection and discharge borehole. 
     
     
         3 . The method of  claim 1  wherein the production borehole is a discharge borehole, and wherein the borehole arrangement further includes an injection borehole having an injection borehole section extending in an injection borehole direction deviating less than 45 degrees from the extension direction, preferably wherein the discharge borehole section extends below the injection borehole section. 
     
     
         4 . The method according to  claim 1  wherein the pressure in the cavity, while the fluid jetting means is operated, is lower than the pressure in the pristine oil sand layer before creating the cavity therein, preferably lower than the bubble point pressure. 
     
     
         5 . The method according to  claim 1  wherein fluid is also injected into the cavity via the discharge borehole. 
     
     
         6 . The method of  claim 1  wherein no borehole in fluid communication with the cavity is arranged, which borehole is a vertical or near-vertical borehole. 
     
     
         7 . The method of any one of  claims 1 - 6 , wherein the production borehole is provided with a tubular of a length adapted to be changed, and wherein the length of the tubular is changed in correspondence with the extension of the cavity in the extension direction. 
     
     
         8 . The method of  claim 1  wherein the production borehole is provided with a pump for pumping the slurry via the discharge borehole to the processing facility and wherein the pump is sealed relative to an inner surface of the liner. 
     
     
         9 . The method of  claim 8 , wherein the pump is axially movable through the production borehole, and wherein the method further comprises axially moving the pump through the production borehole in correspondence with changing the length of the liner. 
     
     
         10 . The method of  claim 8  wherein the pump is driven by a stream of fluid pumped through a conduit extending through the production borehole, and wherein at least a portion of said stream of fluid is injected into the slurry of fluid and oil sand present in the cavity. 
     
     
         11 . The method of  claim 1  wherein at least one of the production borehole section and the refill borehole section extends substantially horizontal, preferably wherein both extend substantially horizontal. 
     
     
         12 . The method of  claim 1  wherein the refill material comprises tailings. 
     
     
         13 . The method of  claim 12 , wherein the refill material is transported from the processing facility to the cavity. 
     
     
         14 . The method according to  claim 1  wherein operating the fluid jetting means and inserting refill material are carried out simultaneously. 
     
     
         15 . The method of  claim 1  wherein inserting refill material into the cavity comprises, after extending the cavity for a selected length, perforating the casing within that length, and pumping refill material from the refill well through the perforations.