Heavy Oil Special Interest Group Luncheon:
Geomechanical Effects on SAGD Productivity & Wellbore and Caprock Integrity
Date: Tuesday, 27 February 2018
Speaker: Dr. Mazda Irani, Ashaw Energy Ltd.
Location: Calgary Petroleum Club
Time: 11:30 am – 1:00 pm
Cost: $45 SPE Members, $55 Non-members, $15 Students
In the SAGD recovery process, the injection of high-pressure, high-temperature steam causes significant stress changes at the edge of the heated zone or steam chamber. These stress changes include shear dilation which can both enhance the absolute permeability and result in horizontal and vertical formation displacements. The importance of considering geomechanical effects in thermal recovery processes has been extensively discussed in the literature, but the prediction and surveillance of the resulting effects, such as the impact on production enhancement and reservoir displacement, have in many cases been neglected. Furthermore, issues related to these geomechanical effects on thermal production have been the subject of considerable debate in the industry with no concluding, meaningful assessments on its effect on reservoir deliverability and production, or on the associated risks which such geomechanical effects have on wellbore and caprock integrity.
This study will focus on identification of the main findings from an extensive monitoring program conducted on the original Steam Assisted Gravity Drainage (SAGD) pilot project conducted at the Underground Test Facility (UTF) in the late 1980s and a seismic program conducted over the last several years by a SAGD operator at a commercial thermal recovery project. The measured displacements and identified dilation shear zones in these applications were compared with a Mohr-Coulomb analytical dilative model. This paper illustrates some of the pros and cons of using such analytical models through comparison of the results based on field evidence of the dilation and shearing effects, and how these mechanisms impact both reservoir productivity (revenue) as well as wellbore and caprock integrity. While the discussion on the geomechanical effects in thermal recovery processes will no doubt continue, this study will provide field-supported results to illustrate both beneficial and potentially challenging impacts which these geomechanical effects can have in a thermal recovery project.
Dr. Mazda Irani is the director of Ashaw Energy Ltd. Dr. Irani has over 15 years of experience to a wide range of thermal activities. He is currently engaged in the design and optimization of different solvent/steam processes, assisting operators in verifying and optimizing their solvent/steam concepts and pilot projects. Dr. Irani was previously employed in technical and supervisory roles with Suncor Energy, RPS Energy and C-FER Technologies. He has published and presented more than 30 technical papers on different aspects of SAGD operation. Dr. Irani holds PhD degrees in petroleum engineering (U of C 2017) and geomechanics (U of A 2012) and three masters degrees in petroleum engineering (MEng), geotechnical engineering (MSc 2003) and structural engineering (MSc 2005).
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