Publications

The geologic study of the Jatibarang Field was performed in 199 lIl992 by Elf Aquitaine Indonesie. It was part of a three phase feasibility study into the utilization of horizontal drilling to improve production from the Jatibarang volcanics. The feasibility study concluded that drilling of horizontal wells would provide a new technology for better management of, and increased recovery from, the unique volcanic reservoir. The geologic portion of the feasibility study was aimed at determining reservoir types in which horizontal drilling and production techniques would lead to improved drainage, and at selecting areas best uited for engineering and drilling phase of the study. Geologic investigation included structural mapping, correlating of volcanic rock types and investigating the relationship between production performance and rock types. Review of test and production data of all wells indicated that the best production came from a volcanic section with a definite well log response. Existing detailed core and sample descriptions, supplemented by new thin sections of available cores, and computer generated mineral percentage logs, showed that the Jatibarang volcanics consisted of correlatable rockllog types. Two main log types were defined representing felsic tuffs and basalticfandesitic lavas. Correlations of log types were made across the entire field, and two main producing log type layers, representing tuff rock types, were defined and mapped. Production data and geologic investigation pointed to several areas in the field where the tuff layer was not as productive as expected due to difference in tuff composition and in effective fracturing. One of these areas was recommended for the engineering and drilling phases of the horizontal well feasibility study.