Abstract: The Impact of New Geoscience Technology on Growing Heavy Oil Production at Cold Lake, Alberta, Canada

Costello, Russell - Imperial Oil Resources Ltd.

Development of non-conventional resources such as oil sands represents both an enormous opportunity and technology challenge. The Cold Lake Production Project (CLPP), Canada's largest thermal recovery operation, uses the cyclic-steam- stimulation process (CSS) to produce 10 API gravity bitumen from the Cold Lake Oil Sands deposit. CLPP started as a small pilot in 1964 and has advanced through successively larger phases of development to the current production level of 130,000 bpd. The key to successful growth and improved economic viability is the development of new technologies that 1) reduce development costs, and 2) increase recoveries. New geoscience technologies are major contributors to meeting these challenges at CLPP.

The reservoir at Cold Lake is the Clearwater Formation, a deposit of unconsolidated fluvial and tidal sands with a total thickness of 40-50 meters and a burial depth of only 450 meters. The Clearwater Formation contains twelve stratigraphic sequences, nine of which are incised valleys. The valleys are filled with either thick, clean, fluvial sands or muddier tidal-bar sands. Near the center of the Cold Lake leases, five of the lowstand incised valleys are stacked one on top of another to produce a thick succession of continuous sands (30-40 meters) with excellent reservoir quality. The use of high frequency, sequence stratigraphy to identify the incised valley complexes is a key technology that provides the template for continued phased development of large, quality opportunities at Cold Lake. The delineation of large opportunities provides the economies of scale that drives down development costs.

A second key area of geoscience technology leverage at Cold Lake has been the development of a relationship between the reservoir lithologies and expected recovery, and the assurance that there is no step-change to sharply lower recoveries as reservoir quality gradually diminishes. Based on production data for 5-10 years on 70 producing pads and for the full range of developed incised valley lithologies, a performance characterization model has been established that accurately predicts EUR to within 10 percent based solely upon lithological characteristics. The performance model eliminates the risk of developing non-economic reservoir.

The increase in recovery factors at CLPP from 13 to 25 percent between 1978 to 1996 has greatly improved project economics. The associated geoscience technology breakthrough has been the use of 4D seismic monitoring to visualize the state of depletion of the reservoir and the location of the remaining unheated bitumen. Attribute analysis is used to seismically differentiate heated and non- heated reservoir and image areal steam conformance. Vertical steam conformance is analyzed using post-stack inversion. The real-time visualization of the 3D reservoir conformance has led to continuous improvements in thermal depletion strategies at CLPP as well as the selective investments in new, follow-up recovery techniques.

AAPG Search and Discovery Article #90933©1998 ABGP/AAPG International Conference and Exhibition, Rio de Janeiro, Brazil