Abstract: Integrated Reservoir Characterization Using Geostatistics and 3D Visualization in the Kern River Field, Bakersfield, California

THOMPSON, TERRY W., and PAUL E. HARNESS, Texaco Exploration and Production, Inc.

In the Kern River field, geostatistical models are generated for key reservoir attributes, including resistivity, temperature, and oil saturation. Identification of bypassed oil and monitoring of steam distribution in the context of an accurate geologic model is achieved through integrated 3D visualization. Operational activities, such as infill or horizontal drilling, focused steam stimulation, or pattern steam-flooding, are guided by this analysis.

Open-hole well log resistivity is used to define the structural and stratigraphic framework of the complex, multi-layered fluvial deposits of the Kern River formation. Digital resistivity control is provided by about 10,000 wells having an average spacing of 150 feet. The distribution of heat and steam in existing thermal projects is based on cased-hole temperature surveys, obtained quarterly in dedicated temperature observation (TO) wells. Approximately 400 TO wells, with an average spacing of 750 feet, are distributed throughout the field. Cased-hole carbon/oxygen (C/O) logs also are run in the TO wells. Accurate and verifiable oil saturation is derived from the annually acquired C/O data.

Using Texaco's 'GridStat' geostatistical program, 3D grids are generated from the resistivity, temperature, and oil saturation well data. These grids are used directly in GridStat and as a source for other 3D visualization applications. The independent grids are integrated to reveal important relationships between lithologic flow units, heat, and oil saturation. Because reservoir surveillance data is acquired on a regular basis, dynamic changes in steam distribution and oil saturation can be measured and compared in a 4D sense. This information is utilized by asset team members to develop specific operational plans for individual wells, steamflood patterns, and projects.

AAPG Search and Discovery Article #90935©1998 AAPG Pacific Section Meeting, Ventura, California