RESERVOIR EVALUATION OF EOCENE AND PALEOCENE SEQUENCE IN SELECTED WELLS OF POTWAR SUB BASIN, PAKISTAN

Abstract

The study area is located in Potwar Sub Basin. To determine the hydrocarbon prospects of the Eocene and Palaeocene strata, petrophysical analysis of Chorgali, Sakessar and Lockhart formations is carried out using a complete suite of wireline logs. The petrophysical results show good porosity ranging from 11 % to 3 % for Sakessar Formation, 7.5 % to 6 % for Chorgali Formation and 11.2 % to 3.5 % for Lockhart Limestone and volume of shale ranging from 6 % to 12 % for Sakessar Formation, 7.6 % to 11 % for Chorgali Formation and 13 % to 21 % for Lockhart Limestone in the studied wells. All of these three wells turned out to be hydrocarbon saturated. The gas effect approves the reservoir capabilities of the formations. The sequence stratigraphic results reveal that two sequences are found in all the under investigated wells, showing the deposition of reservoir formations in two cycles of transgression and regression. Sequence stratigraphic analysis from logs have showed two facies associations in the Eocene and Paleocene sequences. The GR log determines an inner to middle shelf environment for the Chorgali, Sakessar and Lockhart formations. From the correlation of reservoir intervals in the three wells, it can be inferred that the overall reservoir capability increases to the south.