Abstract

This paper describes a geomechanical work program carried out in Karamay heavy oil field, Xinjiang Province, China. Three mini-frac tests were conducted to measure the in-situ minimum stresses in the reservoir sands, shale interbed and caprock shales. Geomechanical triaxial tests under room- and high-temperature were completed to investigate the geomechanical properties of the reservoir sands. These works were motivated by repeating the success experienced in Alberta oilsands reservoirs which proactively use geomechanics to enhance the in-situ thermal recovery. One particular technology, i.e. using geomechanical dilation mechanism for early SAGD start-up was successfully demonstrated on one SAGD well pair in the Karamay reservoir. The results from the mini-frac tests and laboratory tests are presented and compared with the oilsands reservoirs in Alberta, Canada. Differences were discovered. Petrophysical and mineralogical measurements were made and geological origins are sought to explain the difference. Furthermore, relevant results from the dilation start-up demonstration are also shared to the end of this paper. Such success has proven again that geomechanics is equally important in the optimization of in-situ thermal stimulation of the heavy oil reservoirs in Karamay heavy oil field.

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