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Abstract: Impact of 4D Geostatistical Modeling on Heat Management Practices: Midway-Sunset Oil Field, CA

HARRIS, JOHN, Texaco Exploration and Production Inc., Bakersfield, CA; PAUL HARNESS, Texaco Exploration and Production Inc., Bakersfield, CA; MICHAEL PONEK, Texaco Exploration and Production Inc., Bakersfield, CA; JEFF HATLEN, Texaco Exploration and Production Inc., Bakersfield, CA; KEITH SHOTTS, Texaco Exploration and Production Inc., Bakersfield, CA; MIKE LOGAN, Texaco Exploration and Production Inc., Bakersfield, CA; IVAN TEREZ, Texaco Exploration and Production Inc., Bakersfield, CA; DEREK TAYLOR, Dynamic Graphics Inc., Alameda, CA 

Improved understanding of reservoir heat losses stemming from numerical modeling is responsible for dramatic (~30%) steam-rate cuts recently made in the Texaco operated properties of the Midway Sunset Oil Field. Beginning in the second quarter 1999, well log data reflecting the lithologic, thermal and saturation nature of a major Texaco reservoir were compiled, cleaned and spatially interpolated to define the limits and maturity of existing 'steam chests'. These models were interpolated from measured and calculated data using geostatistical algorithms, including ordinary and co-kriging. Due to the large magnitude of data, model rendering had to be optimized by redefining the models into primitive objects so that parallel-processing techniques could be applied. Upon completion of the 3D models, a neural-network was developed to identify the steam chest bounding surfaces using the lithology, temperature and vapor saturation models as inputs. Moreover, heat losses to over and under-burden were calculated for every grid node of the steam chest enveloping surface; the sum of these is the total heat loss from the steam chest to the surrounding rock. Combining these heat losses with other known heat losses (i.e. through vapor recovery facilities, and fluid production) yields that total heat required to sustain the steam chest volume. Since the completion of this modeling project Texaco teams have reduced steam injection by 30% and are expecting to make further cuts in 2000. Currently models are being updated dynamically using recent thermal data so as to further enhance heat management practices and cut costs associated with steam-injection.

HARRIS, JOHN, PAUL HARNESS, MICHAEL PONEK, JEFF HATLEN, KEITH SHOTTS, MIKE LOGAN, IVAN TEREZ, and DEREK TAYLOR

AAPG Search and Discovery Article #90911©2000 AAPG Pacific Section and Western Region Society of Petroleum Engineers, Long Beach, California