"A Super Giant, Part 1" - 3D Modeling to Enhance Field Development Strategies - Midway-Sunset Oil Field, California

PONEK, MICHAEL, JOHN HARRIS, PAUL HARNESS, JEFF HATLEN, MIKE LOGAN, and  KEITH SHOTTS , Texaco Exploration and Production Inc., Bakersfield, CA 

Thermal recovery at the Midway-Sunset Oil Field has been an economic success. However, understanding field wide oil depletion and remaining heat requirements has been a challenge in development of the Potter Sands. Early forecasted steam requirements were based on non-continuous geologic models developed by individual Reservoir Teams. In general, an integrated 3D geologic model was needed to better define the major controlling geologic features for steam migration and for estimating future heat requirements.

In early 1999, Texaco formed a Potter Study Team to develop an integrated geologic interpretation for the Potter Sands in the Midway-Sunset Oil Field. 3D tools such as EarthVision combined with Geolog and detailed surface mapping allowed for rapid and consistent structural framework definition. Over five thousand wells with wireline logs were compiled and normalized for usage in the 3D model. Standard wireline logs combined with geostatistical algorithms were used to develop Lithology, Vapor, and Temperature 3D models. Reservoir details such as desaturated zones, steam chests, and variable oil/water contacts were identified, leading to regional mapping, volumetric analysis and enhanced heat calculations.

Usage of the 3D models by the Reservoir Engineers has led to a much improved heat forecast, resulting in improved field economics. Steam chest volumes and surface areas can now be identified and utilized in the heat calculations. In addition, cold oil opportunities are easily identified and targeted for future oil development.

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