Abstract: 3D Seismic Imaging of the Shallow Tulare Sandstone at South Belridge Field, CA - Results and Impact on Reservoir Development

MYERS, G. A., WRACHER, M.D., and CARLSEN, M.M., AERA Energy LLC, Bakersfield, CA

In early 1997, AERA Energy began an aggressive development program to increase heavy oil production at the South Belridge field. A 4.2 square mile 3D seismic survey was acquired to better understand geologic risks and guide the development. A decision tree spreadsheet was used to determine the economic impact, in terms of risked NPV, that 3D seismic would have on this project.

The shallow depth of the Tulare (700-1500 feet) required a very high source and receiver effort (1,100 and 2,225 per square mile, respectively) to build fold to acceptable levels and achieve the required resolution. Intensive first break analysis and iterative application of static solutions, as well as detailed velocity analysis were also keys to imaging this shallow target.

Interpretation of the 3D data set resulted in the identification and mapping of a series of northwest-southeast trending, primarily normal offset, faults which bound a subsidiary high west of the main structural crest. A set of orthogonal crossfaults offset the bounding faults and the structural high itself, resulting in a structural style similar to Kettleman Hills. Comparison to an adjacent development area drilled without the benefit of seismic illustrates the value of the 3D data set. 3D seismic data provided a sign)ficant improvement in structural imaging and fault location prediction leading to better 1) horizontal well design, 2) pay completed/drilled lateral feet, 3) steam injector strategy, and 4) volumetric determinations.

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