Title: Hot-gas injection in Asphalt Ridge tar sand
Abstract: Bench-scale experiments were conducted in a one-dimensional reactor to evaluate the potential of hot-gas injection for the in situ recovery of oil from tar sand. The use of hot gas was examined both as a preheating technique before a steamflood and as an alternative oil recovery process utilizing bitumen pyrolysis. Process results were compared with results from previous thermal recovery experiments utilizing steam displacement and reverse combustion. Hot-gas injection can be successfully used to preheat tar sand provided a reasonably slow heating rate is maintained. Preheat temperatures up to 500/sup 0/F (260/sup 0/C) can be achieved producing a viscous oil bank, which could form a liquid blockage and plug the tar sand matrix. The oil recovery from the subsequent steamflood experiment approached 42 wt. % of the initial bitumen, which is identical to the oil recovery from previous electrically preheated steamflood tests and indicates that the bitumen was not adversely affected by extended preheating periods at low heating rates. Oil yields from hot-gas injection improved with increasing temperatures, ranging from 9 to 73 wt. % of the initial bitumen as process temperatures were increased from 520/sup 0/F (270/sup 0/C) to 1040/sup 0/F (560/sup 0/C). Since bitumen pyrolysis was not observed more » at temperatures below about 600/sup 0/F (315/sup 0/C), the oil yield below the pyrolysis temperature was probably caused by the viscosity reduction and thermal expansion of the bitumen. Steamflooding appears to be the least efficient thermal process evaluated for the recovery of oil from Asphalt Ridge tar sand, whereas reverse combustion and hot-gas pyrolysis yield greater net gains in energy production. 12 refs., 2 figs., 5 tabs. « less
Publication Year: 1985
Publication Date: 1985-05-01
Language: en
Type: article
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