Geochemical characterization and hydrocarbon potential of Cambay Shale in the south Cambay Basin, India: implications to unconventional resource development

• Published in: Arabian journal of geosciences 2022-03, Vol.15 (5), Article 452
• Main Authors: De, Sanjukta, Aastha, Sengupta, Debashish
• Format: Article
• Language: English
• Subjects: Analysis; Comparative analysis; Comparative studies; Earth and Environmental Science; Earth science; Earth Sciences; Geochemistry; Hydrocarbons; Kerogen; Oil; Oil and gas exploration; Oil exploration; Organic carbon; Original Paper; Peak oil; Petrography; Petrology; Pyrolysis; Reflectance; Resource development; Rocks; Saturation; Saturation index; Sedimentary rocks; Shale; Shales; Total organic carbon; Unconventional resources
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-022-09738-4

In the present study, 130 shale samples of Cambay Shale were selected from two wells of the south Cambay Basin in the Jambusar-Broach block, India, to evaluate their source rock potential. Analysis with an integrated approach has been carried out using organic petrography, mean random vitrinite reflectance (R̄r), total organic carbon (TOC) estimation and Rock–Eval (RE) pyrolysis techniques. The variation of the TOC (wt%) values of the selected samples is in the range of 0.9–5.3% with an average value of 2.5%. Organic petrography of the shale samples reveals vitrinite as the major maceral type followed by liptinite and inertinite. The analysis of RE data of the shale samples also indicates the prevalence of type III as the dominant kerogen type. Based on the results of TOC estimation, hydrogen index and generation potential, the analysed samples are indicative of good to excellent source rocks with poor to good potential to generate hydrocarbon. R̄r (0.53–0.88%), T max (413–467 °C) and production index (0.02 to 0.5) indicate that thermal maturation of the shale samples lies from immature to peak oil window. Analysis of oil saturation index and oil crossover effect indicates a substantially higher risk of production of oil from the Cambay Shale based on geochemical consideration. The variability of source rock quality of the Cambay Shale in different blocks has been analysed. A comparative study of the Cambay Shale in the studied region with some of the producing shale plays in the world has been done based on organic geochemical characteristics.