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, the method comprising: an injection borehole having an injection borehole section extending in an injection borehole direction and a discharge borehole having a discharge borehole section extending in a discharge borehole direction below the injection borehole section, wherein both the injection and the discharge borehole directions deviate less than 45 degrees from the extension direction; creating a cavity in the layer, the cavity being in fluid communication with both the injection and the discharge borehole sections; extending the cavity by operating fluid jetting means via the injection borehole against a wall of the cavity to obtain a slurry; and withdrawing the slurry from the cavity via the discharge borehole to a processing facility.

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 an injection borehole having an injection borehole section extending in an injection borehole direction, and a discharge borehole having a discharge borehole section extending in a discharge borehole direction below the injection borehole section, wherein both the injection and the discharge 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 both the injection and the discharge borehole sections;   c) extending the cavity by operating fluid jetting means via the injection borehole to jet a stream of fluid against a wall of the cavity, to obtain a slurry comprising fluid, hydrocarbon material, and sand; and   d) withdrawing the slurry from the cavity via the discharge borehole to a processing facility for processing the slurry.   
     
     
         2 . 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. 
     
     
         3 . The method of  claim 1  wherein fluid is also injected into the cavity via the discharge borehole. 
     
     
         4 . The method of  claim 1  wherein no injection or discharge borehole in fluid communication with the cavity is arranged, which borehole is a vertical or near-vertical borehole. 
     
     
         5 . The method of  claim 1  wherein both the discharge borehole and the injection borehole are provided with a tubular of a length adapted to be changed, and wherein the lengths of both tubulars are changed in correspondence with the extension of the cavity. 
     
     
         6 . The method of  claim 5  wherein changing the length of at least one of the tubulars comprises operating a shortening device, in particular wherein the tubular is made of a non-metal, such as a plastics material. 
     
     
         7 . The method of  claim 1  wherein the discharge 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. 
     
     
         8 . The method of  claim 7  wherein the pump is axially movable through the discharge borehole, and wherein the method further comprises axially moving the pump through the discharge borehole in correspondence with changing the length of the liner. 
     
     
         9 . The method of  claim 1  wherein the pump is driven by a stream of fluid pumped through a conduit extending through the discharge borehole, preferably, wherein at least a portion of said stream of fluid is injected into the slurry of fluid and oil sand present in the cavity. 
     
     
         10 . The method of  claim 1  wherein at least one of the injection borehole section and the discharge borehole section extends substantially horizontal. 
     
     
         11 . The method of  claim 1  wherein the method further comprises inserting refill material into the cavity. 
     
     
         12 . The method of  claim 11  wherein the refill material is transported from the processing facility to the cavity. 
     
     
         13 . The method of  claim 11  wherein the borehole arrangement in the earth formation includes a refill borehole having a refill borehole section extending in a refill borehole direction deviating less than 45 degrees from the extension direction. 
     
     
         14 . The method of  claim 11  wherein the refill borehole section is arranged below the discharge borehole section. 
     
     
         15 . The method of  claim 11  wherein inserting refill material into the cavity comprises
 providing a refill borehole having a refill borehole section extending in a refill borehole direction deviating less than 45 degrees from the extension direction, the refill borehole section being provided with a casing; 
 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.