Geo-microbial and geochemical evidences in the near surface soils of Jamnagar sub-basin, Saurashtra, Gujarat, India: implications to hydrocarbon resource potential

摘要: The Jamnagar sub-basin of Saurashtra, Gujarat is considered geologically prospective for hydrocarbons by Directorate General Hydrocarbons (DGH), India. However the major part covered Deccan Traps, hindering exploration Mesozoic hydrocarbon targets. In India, significant finding in stratigraphic sequence has not been established, as sediments underlying Traps. Detection and mapping below Trap a long-standing complex geophysical problem facing oil industry. vast sheet volcanic cover, which overlies acts shield inhibit effective use conventional seismic techniques. Surface geochemical techniques based on microseepage from subsurface accumulations, have potential to evaluate prospects petroleum exploration. view this, surface survey adsorbed soil gas microbial analysis was conducted sub-basin, total 150 near samples were collected evaluation resource Basin. Microbial revealed high bacteria counts methane (1.32×106 cfu/gm), ethane (8.50× 105 propane (6.86×105 cfu/gm) butane oxidizing (5.70×105 sub-basin. bacterial concentration distribution maps show three distinct anomalies study area, indicating at these places. investigations showed presence gases (C1) 1 518 ppb Ethane plus (ΣC2+) 977 respectively. Further, carrying out integrated geo-microbial geo-chemical studies with anomalous zones nearby Khandera, Haripur, Laloi areas could probably aid assess true On basis prospecting area appears be warm zone needs detailed investigation other geo-scientific methods. Integrated shown that Saurashtra sediment thickness Traps can future corroboration light gaseous suggests its efficacy one tool hydrocarbons.