Abstract

The Mabee Field is one of three fields currently targeted for enhanced oil recovery utilizing CO₂ by Texaco in the Permian Basin. The purpose of the individual CO₂ groups was to provide an accurate reservoir description that would not only support the past history of the field, but would predict future reservoir performance and recoveries along with providing for the monitoring of the CO₂ miscible flood after its initiation.

One of the major tasks in the reservoir description was to determine the original oil in place utilizing all available log and core data. The purpose of this paper is to describe the method which was used to calibrate modern porosity logs to core and to normalize old neutron logs in order to obtain reservoir height or PHI*H.

The Mabee Field has 650+ old neutron logs of which about 75 cannot be used at all because they were stimulated with nitroglycerine. The Mabee Field also has about 150 modern porosity logs. In addition, approximately 85 wells have been cored at the Mabee Field, of which only 35 wells have the core report and no actual core for description. All of the logs and core data have been digitized. Before the logs were sent out for digitization, all pertinent information such as logging company, tool model no., hole size, casing point, casing size and weight, source to detector spacing, etc. were recorded and entered on to a spreadsheet to be used in calibrating the logs to core porosity.

The log analysis, mapping and data base management necessary to obtain PHI*H were done on a personal computer. It could not have been accomplished within the incurred time constraints without it.