Tertiary Development of Heavy Oil Sands through Thermal Stimulation in the Wilmington Oil Field, California: A Geological Perspective

Donald D. Clarke, Christopher Phillips, Michael J. Henry, Richard W. Strehle, and Linji An

In 1995, a DOE cost share project was initiated to extend thermal recovery in the Tar Zone, Fault Block II of the West Wilmington Oil Field, California. The project involved the collection of old oil well data and the construction of a modern digital data base in order to develop a deterministic geological model. The plan was to rigorously define the geology such that horizontal wells could be accurately placed within the sands containing heavy oil to facilitate gravity drainage. A detailed deterministic geological model was constructed using a state of the art 3-D mapping and modeling package.

Beginning in July, 1995, five observation wells were drilled. Data inconsistencies were revealed when core hole OB2-003 was drilled. It was discovered that the data used to make the maps was corrupted; as a result, the predicted coring point was missed by more than 20'. Significant modifications to the data base were required due to inaccurate subsidence corrections in the original data set. Horizontal wells were then laid out based on the revised data and the geological model was completely reconstructed. Detailed cross sections extracted from the model were use for geosteering. These cross sections proved to be highly accurate and five more wells are now planned for the target sands. This detailed deterministic model will be further refined and combined with our geostatistical mode or geological control in an advanced reservoir simulator. If successful, the thermal stimulation project will be expanded to other fault blocks.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California