Stakeholders in the in-situ oilsands development take the caprock integrity issues very seriously. The industry is faced with the challenge of determining an optimal operating pressure in the reservoir. In general, the pressure should stay low enough to ensure the caprock integrity while being high enough for enhanced oil production and economics. This paper presents a comprehensive work program on the subject for a shallow oilsands play.

Caprock integrity is concerned about the induced stress and deformation in the caprock during the thermal stimulation of the oilsands reservoir. A mini-frac test program was undertaken to define the original in-situ stress state. Laboratory tests were carried out to measure the deformation and strength properties. Simulations were run to calculate the induced stresses and evaluate them against the mechanical strength. Consequently, a factor of safety is delivered for a given operating pressure. This paper will cover all these geomechanical work components. Both field data and theoretical considerations are included to augment the technical descriptions.

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