Structural Division Talk

3D Seismic Estimates of the Anisotropic Stresses in the Athabasca oil Sands Reservoirs for Caprock Integrity

Speaker: Carmen C. Dumitrescu,  Terra-IQ Ltd.

February 06, 2020
Schlumberger Canada, Province Conference Rooms 2nd floor Palliser One Building, 200, 125 9th Avenue SE 

12:00pm: Talk Starts


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Everyone is aware that caprock integrity is a safety issue in thermal production of the oil-sand reservoirs. In the Athabasca Oil Sands basin, the Lower Cretaceous McMurray Formation reservoir is overlain by the Clearwater Formation. The formation shales form the reservoir caprock and have the role of blocking the vertical migration of the steam by confining the stresses and the deformations induced during the thermal oil recovery process. Accurate knowledge of the stress distribution in the subsurface is necessary and most of the time this is obtained from mini-frac tests who provide localized information.

A new method to integrate all our data from cores, piezometers, dipole sonic wells and multicomponent seismic surveys to deliver accurate and thorough three-dimensional estimates of the anisotropic stresses in the overburden will be presented along with workflow and results. Estimates of the total and effective stresses are available because the formation pore pressure is considered.

The formation pore pressure is modelled from local pressure measurements which show values below the normal hydrostatic regime in the Clearwater Formation. The predicted magnitudes of the three principal stresses (vertical, minimum and maximum horizontal) indicate correctly that the Clearwater Formation is under a normal stress regime. There is excellent consistency between the minimum horizontal stress calculated with this method and mini-frac values. This good agreement shows that, for the case study, this new method successfully aids in a deeper understanding of the in-situ anisotropic stress field, which is critically important for the assessment of caprock integrity. 


Dr. Carmen Dumitrescu is the owner and founder of Terra-IQ Ltd., an independent consulting company specialized in providing oil companies with expertise in leading-edge geophysical technologies for reservoir characterization and seismic data interpretation (

Carmen was involved in a variety of projects to estimate reservoir properties of 2D and 3D seismic data in clastic, carbonate, and heavy oil, using conventional, multicomponent and time-lapse seismic data. She has presented and published numerous papers at the CSEG, EAGE and SEG Annual Meetings. Carmen has a degree in Geology, Geophysics and Engineering from University of Bucharest, Romania and has a Ph.D. in geophysics from the University of Calgary, Canada. She is an active member of CSEG, SEG, EAGE, SPE and APEGA and the Chair of the SEG Meeting Review and Planning Committee.