Publications

This paper presents the successful application of the advanced mud gas analysis in one recently drilled development wells in the “A” field, East Java Basin. The targeted reservoirs are stacked platform carbonates with multiple hydrocarbon bearing zones and large uncertainties in fluid type, contacts and reservoir connectivity. The uncertainties are partly as a result of insufficient well log data, such as pressure and fluid sample due to the difficulty in obtaining them during the wireline operations. The advanced mud gas acquisition and analysis was carried out as a mitigation plan to reduce the fluid uncertainties. The acquisition process involved the use of membrane-based probe extraction and delivered the gas through 3 m conditioner gas line to the high speed measurement chromatograph system which could provide high quality and accurate C1-C8, Benzene, Toluene, CO2 and N2 gases content. Several cross plots of gas ratio utilizing the gas components and aromatic were run and the result was validated by correlation and comparison with offset well logs, well tests and PVT data. The result of the analysis supports the wireline log evaluation process by highlighting the main zones of interest and reduce the uncertainties in selection of intervals for testing. Four (4) intervals that have not been tested in the previous wells were found to be encouraging and hydrocarbon bearing reservoirs were later confirmed with DSTs. The method has proven to be reliable in this case and would also be considered in the upcoming exploration and development wells.