Patent ID: 6152356
Filing Date: 2000-11-28
Classification: E21B,E21C

Abstract:
A method for the hydraulic removal of bitumen from a tar sand deposit located beneath surface overburden comprising:a) forming a borehole through said overburden into the tar sand deposit;b) affixing a casing into the borehole said casing having a proximal end above the grade of said surface overburden and extending downward through said overburden into said tar sand deposit and terminating at a distal end, said casing having a central opening at said proximal end through which a mining tool may be inserted and having aggregate entry means and bitumen/diluent removal means adjacent said proximal end above grade through which aggregate material may be added to the casing interior and from which bitumen/diluent may be removed from said casing;c) inserting into said casing a mining tool comprising concentric inner and outer tubes, each having generally cylindrical walls and proximal and distal ends with the proximal ends extending above grade and above the proximal end of said casing, the interior of said inner tube forming a slurry outlet channel, the annular space between said inner and outer tubes forming an annular water/diluent inlet channel and the space between said outer tube and said casing further forming an annular mining cavity access channel, said mining tool further comprising walled ducts at the distal end of said outer tube and forming a continuation thereof and an interconnecting manifold extending distally from the distal end of said inner tube,i) said inner tube having connecting means at its proximal end above said casing for conveying a slurry out of said mining tool and having a distal floor separating said inner tube from said manifold said inner tube having intake grates in said cylindrical wall just above said distal floor for allowing entry of a slurry from a cavity being mined into said slurry outlet channel;ii) said outer tube having connecting means at its proximal end above said casing for conveying a water/diluent mixture into said water/diluent inlet channel, said outer tube merging into walled ducts at its distal end portion so as to expose said intake grates of said inner tube, said walled ducts extending distally beyond the distal end of said inner tube and feeding into said manifold;iii) said manifold being defined by said distal floor of said inner tube, a manifold floor and an interconnecting cylindrical wall, said cylindrical wall having inlet apertures in fluid communication with said walled ducts and having located adjacent said manifold floor outwardly extending high pressure nozzles for injecting jets of hot water/diluent passing from said water/diluent intake channel, through said walled ducts and into said manifold;said mining tool extending through said casing and into said borehole such that said intake grates and high pressure nozzles are in said tar sand deposit;d) adding aggregate through said aggregate entry means sufficient to cover said intake grates of said inner tube;e) alternately rotating said mining tool horizontally over at least 180.degree. rotation while injecting into said outer tube, under high temperature and pressure, a water/diluent mixture causing said water/diluent mixture to pass through said water/diluent inlet channel, walled ducts and manifold and out said nozzles under high pressure and temperature such that a cavity is formed in said tar sand deposit by the temperature of the hot water softening the tar sand deposit and the force of the water jets and impact of the aggregate scouring the tar sand to remove tar sand from a developing floor and walls of a water filled cavity being formed in the deposit such that the bitumen in the tar sand interacts with the diluent present in the hot water lowering the viscosity of the bitumen and separating it from the sand particles such that the bitumen/diluent rises to the surface of the water in the cavity thereby forming a bitumen/diluent upper phase and a water/sand slurry phase at the bottom of the water filled cavity,removing bitumen/diluent phase through said bitumen/diluent removal means in said casing, withdrawing through said intake grates a water/sand slurry phase along with residual bitumen/diluent remaining in said water/sand slurry phase into said slurry channel and which passes upwardly and out of said mining tool for processing or disposal;f) lowering said mining tool in said casing and borehole as the mining progresses such that the water/diluent passing through jets scours the floor of the developing cavity in said tar sand deposit and adding such aggregate as is necessary to optimize the scouring action of the combination of aggregate and high pressure water/diluent jets.