Abstract Oil sands geomechanics plays an important role in the oil sands recovery processes, such as surface mining, cyclic steam stimulation and SAGD, which are widely applied in the development of oil sands resources in Alberta, Canada. Coupled reservoir geomechanical simulation techniques have been developed and used for the design of in situ recovery processes, particularly for SAGD. Thus, a realistic geomechanical model of oil sands material is a critical component in these reservoir geomechanical simulations. This paper presents the development of an oil sands model based on the analysis of laboratory testing results provided by different researchers, including Oldakowski, Samieh and Wong, and Touhidi-Baghni. On the basis of this analysis, 25 numerical experiments were conducted to match these laboratory tests, including the stress paths, as those applied in the laboratory experiments. Consequently, a comprehensive geomechanical model of oil sands material was established based on these numerical experiments. The proposed strain softening model parameters, such as the modulus of elasticity, peak and post-peak friction angle, and dilation angle, can be applied in the coupled reservoir geomechanical simulations of thermal recovery processes, including the SAGD process.
INTRODUCTION The development technology of oil sands reserves in Alberta, Canada, introduced a series of issues associated with the geomechanical properties of oil sands material. The surface mining technology and in situ recovery processes, such as cyclic steam stimulation (CSS) and steam assisted gravity drainage (SAGD), are both widely applied. Oil sands geomechanics has been studied in these areas, such as the improvement of surface mining efficiency, reservoir deformation regarding in situ thermal recovery, hydraulic fracturing during the cyclic steam stimulation process, and the prediction of in situ recovery performances.
The geomechanical properties of oil sands have been stud\ied extensively since 1970s(1) (2) (3) (4) (5) (6). With increasing experience in sampling and testing, good quality data can be obtained from lab testing. In this paper, the most recent laboratory testing results from Oldakowski(4), Samieh and Wong(5), and Touhidi-Baghini(6), are analyzed and simulated in order to obtain a representative geomechanical model of oil sands material.
Laboratory Testing on Oil Sands Oldakowski's Lab Tests. Oldakowski(4) conducted a series of triaxial compression tests with different stress paths based on relatively undisturbed oil sands cores to characterize the stress-strain relationships of oil sands material. These oil sands cores were obtained from wells drilled at the AOSTRA Underground Facility Test Phase A site in 1987. In total, 23 oil sands samples were obtained from wells AT3 and AGI4 at two stratigraphic units, E and D, which consist of the richest oil sands at the UTF site.