Evaluation of Carbonate Reservoirs for Thermal Bitumen Recovery
Authors: N. Edmunds, K. Barrett, M. Cimolai, and A. Mai - Laricina Energy Ltd.
Source: This paper was prepared for presentation at the 2010 Heavy Oil Development International Seminar in Panjin City, China, September 15-17, 2010
The oil sands of Alberta, Canada, have become a major new source of world supply, especially with the commercial application of steam-assisted gravity drainage (SAGD) to the McMurray Formation. For example, Canadian oil sands now make up the largest component of US oil imports. Continued expansion of the production capacity of this resource, the world’s largest single hydrocarbon accumulation, will continue for many decades to come.
To date, this development has occurred only in clastic reservoirs. There are, however, additional major accumulations in underlying carbonate reservoirs, notably over 400 billion barrels in the Grosmont Formation alone, and these are now beginning to receive attention for development.
This paper reviews the general principles of carbonate reservoir geology, followed by a review of SAGD principles and a discussion of key petrophysical properties for thermal evaluation as well as SAGD physics in dual porosity systems. Implementation in stratified reservoirs, where regional barriers may isolate adjacent pay zones is also reviewed.
Steam/oil ratio determinants are reviewed to demonstrate the (non-linear) sensitivities to critical formation parameters, such as porosity; and then various heavy-carbonate reservoirs are compared across typical parameters. Carbonates are demonstrated to present viable thermal recovery candidates under appropriate conditions, while holding significant opportunities with developing technologies.