Abstract

Over the past 50 years, in-situ recovery methods for oil sands reservoirs have evolved and the patent literature is rich with different well designs, operating conditions, and recovery mechanisms. Here, the patent and literature has been analyzed to understand those features of in-situ recovery technologies that persisted through time. Over 250 hundred patents covering different well designs and injectants have been examined. A simple example of a persistent technology is the horizontal well: Steam-Assisted Gravity Drainage (SAGD) is enabled by horizontal well technology; the vertical equivalent of SAGD is not feasible as an economic recovery process. Cyclic steam stimulation (CSS) and steam-assisted gravity drainage (SAGD) are now over two decades old since invention and at this point there are few new technologies on the table which are being researched or evaluated. Most new technologies, for example, thermal-solvent, electrical heating with solvents, and toe-to-heel combustion are incremental adds on existing technology ideas proposed in the patent literature years to decades ago. Here, an analysis has been done to understand the evolution of in-situ oil sands recovery technology and what features have enabled economic recovery oil sands resources. The results reveal that a small number of features arising from the oil sands recovery process ideas dreamed, proposed, and developed over the past 50 years account for the success of current commercial oil sands recovery methods.

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