Print this pageABSTRACT: Rock and Oil Properties Used to Confirm and Differentiate Proven Pay and Low Resistivity Pay in a Well Drilled with Oil-Base Mud, Offshore Gulf of Mexico
SCHAFER, DANIEL, ARCO Oil and Gas Company, Houston, TX
Wells drilled with oil-base mud pose increasing problems relative to confirmation of oil and gas pays during and after drilling of the well. Rock properties and oil geochemistry are used to confirm proven pay and low resistivity pay in two sandstone intervals in a well drilled with oil-base mud in the offshore Gulf of Mexico. Oil-base drilling fluid makes the differentiation between oil, gas, and logged resistivities difficult without some additional rock and oil signature support. Thin section, XRD, and SEM rock analyses, in conjunction with RFT results, were used to support the low resistivity pay acknowledged in one of the sands vs. high porosity and permeability pay seen in the second sand. These rock analyses suggest that the phenomena of diagenetic cessation after hydrocarbon em lacement may have been observed. Additionally, oil geochemistry from RFT samples confirmed the presence of reservoir hydrocarbons significantly different from the oil signature of the oil-base mud system in both sand intervals.
AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)