Computerization of the directional surveys for the Huntington Beach offshore field aided materially in successful secondary-recovery operations under adverse conditions. A very detailed and accurate geologic study of the reservoirs was necessary for waterflooding and steam-stimulation operations in the thick, intensely faulted sandstone sections.

The computer was used to recalculate the directional surveys, interpolate the geologic markers, and establish

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a data file. Angle averaging was chosen as the most practical and accurate method of computing the survey. Programs were written to plot tops for maps and to project the tops into a vertical plane for cross sections. The final result was a geologic interpretation that was consistent for 5 maps and 43 cross sections.

The computer also was used to plot the well courses. Many wells had to be redrilled for the secondary-recovery program. The courses have to be controlled closely to avoid collisions and to make effective completions. The data file is searched for wells that might interfere with the proposed course. These are plotted so the drilling engineer will be aware of potential problems.

The software development and computer costs were minor compared with charges for conventional engineering and geologic studies and for data preparation. The method is practical and easy to use, and has been applied to other fields in California.

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