Abstract

The Lower Barmer Hill (LBH) source rocks deposited in the syn-rift grabens within Barmer Basin, western India has substantial unconventional shale potential. The organic-rich shales deposited during a major transgressive event in a deep lacustrine setting during Eocene times. Unlike North American Shale plays deposited in passive margin and/or intercontinental marine setup, Barmer Basin source rock is deposited in the syn-rift grabens and each graben behave as a separate sub-basin, with different lithofacies and heat flow history. Potential target areas have been assessed on a play-based approach and volumetric approach have been used to estimate hydrocarbon in-place (HIP) and technical recoverable resources (TRR). Each of the grabens and thereby plays and sub-plays have been ranked based on the opportunities, uncertainties and risk assessments. Here we demonstrate the results of first unconventional well drilled in the graben and its implication on the unconventional opportunities within the graben. The pilot vertical well V&V UC-1 proved 4.8 mmboe/km2 of HIP. The well encountered Hybrid interbedded turbiditic play and pure shale play analogous to Uteland Butte member in Uinta Basin, north Wyoming, USA. Petrophysical interpretation of wireline logs constrain the net pay thickness within the sub-play segments. The total organic content (TOC) measurement in the organic rich shales reaches upto 4 wt%. Rock eval and vitrinite reflectance data quantifies the thermal maturity of the source rock in the graben. The results show the uncertainty in thermal maturity measurements and however it ranges black oil to late volatile oil window suitable for unconventional systems. Further core studies integrating the V&V-UC-1 results is critical to determine optimal location for well testing as next steps of exploring the unconventional potential