The effective source rocks in the north Cambay Basin, India

Source rock screening reveals five laterally extending potential sources (P S) in the Paleogene. The PSs are SR5 and SR6 in dominantly marine early Eoc ene to late Paleocene Cambay Shale formation, and SR7, SR8/9, and SR11/12 i n dominantly freshwater early Paleocene Olpad formation. Only 3 PSs, SR11/1 2, SR8/9, and SR7 have attained vitrinite reflectance of 0.75% at 45, 7, an d 2 mybp, respectively. Chromatographic and isotope data of oils and PS sam ples suggest that mainly the Olpad source rocks: SR7 and SR8/9 contributed to the discovered oils. The Cambay Shale source rocks, SR5 and SR6, contrar y to the prevalent view, possibly have no significant contribution towards the accumulated oils. (C) 2001 Elsevier Science Ltd. All rights reserved.