PYROLYSIS-GAS CHROMATOGRAPHY OF ASPHALTENES KEROGENS FROM SOURCE ROCKS OF THE GANDHAR-FIELD, CAMBAY BASIN, INDIA

Pyrolysis-gas chromatography of rocks from three exploratory wells in the Gandhar area of the Cambay Basin, India, reveals that the organic matter is dominated by input from higher land plants. The pyrograms of asphaltenes and kerogens demonstrate that the Hazad and Cambay Shale were deposited in different environments with the former being an over all regressive deltaic environment and the latter a marine transgressi ve sequence. Studies of TOC (values range from 1 to 2.6%), Rock-Eval ( HI values range from 70 to 183), pyrolysis-gas chromatography, vitrini te reflectance (R(o) range from 0.4 to 0.8), bitumen extracts and isot opic ratios demonstrate that both Hazad and upper Cambay Shale can act as effective source rocks wherever they are thermally mature.