Abstract

The Olpad Formation marks the onset of sedimentation in Cambay basin over the Deccan basalt and was deposited as braided stream and lacustrine deposits in an overall alluvial fan complex during Paleocene. The sediments were essentially derived from the basalt terrain exposed all along the rifted eastern margin and thus comprise mostly basalt derivatives having variable thickness. Due to its proximity to the source rock facies in the overlying Cambay Shale Formation in the down dip lows, the hydrocarbon prospectivity of the Olpad Formation is quite encouraging and is one of the important objects of exploration. As the distribution of Olpad sediments was influenced by the basin architecture, there is large variation in its lithofacies characteristics in both time and space. Mapping of the facies heterogeneity and its petrophysical characteristic is thus a challenge in preparation of facies distribution map for the exploration of the Olpad Formation. The present paper provides details of application of an innovative non-seismic technique used for of calibration of the lithofacies heterogeneity with corresponding electrofacies in Olpad Formation which can act as guide for identification of lithofacies variations on the basis of logs over a large area and in preparation of the regional facies map.