Elemental characterization of thermal-hydraulic-mechanical-chemical properties of caprock and interbedded shale under SAGDOX process in Athabasca oil sands

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Steam assisted gravity drainage (SAGD) is a commercially available in-situ recovery process for bitumen from clean oil sands reservoirs in Alberta, Canada. In low-quality oil sands reservoirs, the spatial extent of the steam zone and the gravity drainage are significantly impeded by interbedded shale layers in the reservoir. SAGD becomes uneconomical, particularly in the current low oil price environment, in low-quality reservoirs. A post SAGD oxidation process (SAGDOX) is one of the potentially viable in-situ recovery processes to improve the recovery for low-quality oil sands reservoirs. In SAGDOX process, oxygen gas is co-injected with steam in every other SAGD horizontal parallel injector well, and the oxidation temperature at the reaction front may be in the range of 400-600 C, which are higher temperatures than those encountered in SAGD of 200-300 C. At such high temperatures, interbedded shales may disintegrate, and the drainage efficiency may be enhanced to increase steam growth and oil drainage. To ensure the success of SAGDOX and protection of the environment, the caprock must be able to withstand the high temperatures and pore pressures encountered in the field. To date, there is limited understanding of high temperatures and pore pressures on the structural and hydraulic properties of caprock and interbedded shale materials. The overall objective of the proposed research is to develop a strong scientific knowledge base to advance our understanding of the effect of high temperatures on behaviour of caprock and interbedded shale in thermal recovery processes. The research outcomes include new knowledge and new models, all of which will enable energy operators and regulators to understand, predict and manage the heavy oil recovery processes. Oil sands in Alberta is one of the largest natural resources in Canada. In-situ thermal recovery processes such as SAGD and other hybrid SAGD are increasingly important to the recovery of accessible vast resources in Canada. The work of this research moves SAGD recovery forward, supporting the development of recovery methods that are feasible, economical, safe and sustainable.