Reservoir Heterogeneity Delineation through Colored Inversion of High Resolution Seismic Data in Mangala Field, India

Abstract

Summary The Mangala Field is located in the northern part of the onshore Barmer Basin in Rajasthan, India. The primary reservoir is the Upper FM1 member of the Fatehgarh Formation, composed of single-storey and multi-storey stacked, meandering channel sands. Individual sand thicknesses vary from 3m to 7m, with net-to-gross ranging from 18% to 78%. Correlation of the fluvial channel sands and floodplain shales based on well data in such a heterogeneous system poses a major challenge for reservoir characterization. The conventional 3-D seismic data with dominant frequency of 25Hz does not resolve the thin stratigraphic units in FM1. High resolution Sparse Layer Inversion was performed to enhance thin sand definition. This paper demonstrates how Colored Inversion of high resolution 3-D seismic data has helped in mapping the distribution of thin FM1 channel sands in Mangala Field. Results of inversion have also provided greater understanding of the connectivity and lateral continuity of these thin fluvial reservoir sands. The band-limited relative P-impedance guided reservoir model provides improved results in terms of overall reservoir pressure and well productivity, leading to a more reliable production forecast.