Research Areas & Highlights

Research Areas

Exploration of marine gas hydrates
Imaging sub-volcanic sediments
Understanding geo-tectonics of several provinces (onshore & offshore) of India, and
Expertise built in inversion, modeling, advanced processing and interpretation of seismic data

Research Highlights

Scientific Contribution on "Exploration of Gas-hydrates" by CSIR-NGRI

Various forms of unconventional and renewable energy resources are sought for energy-starving countries like India towards the energy security. Gas-hydrates that naturally occur in shallow sediments along the outer continental margins and permafrost regions are envisaged as one of the best alternatives, as their energy content is more than two times that of the total fossil fuels (oil, gas and coal). The amount of methane prognosticated in the form of gas-hydrates along the Indian margin is so huge that only 10% recovery can meet India's overwhelming energy requirement for about 100 years. Successful production tests in USA, Canada, Japan, and China provide great hopes that viable production of gas-hydrates for commercial use is not too far. Hence, delineation and assessment of gas-hydrates using various geo-scientific data have been very imperative. CSIR-NGRI has taken up this research, and established state-of-the-art Gas Hydrate Research Center with world-class facilities for inversion, processing, modeling & interpretation of seismic data for evaluating the resource potential of gas-hydrates along with laboratory facilities to understand the formation and dissociation kinetics aiming for providing inputs to develop suitable production technology. Salient features with references are described below:

Prepared gas hydrates stability thickness map along the Indian margin (Sain et al., 2011), and Illuminated gas-hydrates scenario within the Indian exclusive economic zone (Sain & Gupta, 2012; Sain, 2012).
Proposed new approaches for the delineation and characterization of gas-hydrates based on several seismic attributes (Satyavani et al., 2008; Ojha and Sain, 2009; Sain et al., 2009; Sain & Singh, 2011; Satyavani & Sain, 2015).
Developed innovative methods for quantitative assessment of gas-hydrates (Ghosh & Sain, 2008; Ojha et al., 2010; Ghosh et al., 2010a, b; Sain et al., 2010; Shankar et al., 2013, 2014; Ojha & Sain, 2013; Wang et al., 2013, 2014; Jana et al., 2016; Satyavani et al., 2015).
Identified prospective zones of gas-hydrates in Krishna-Godavari (KG), Mahanadi and Andaman offshore using available industry-standard seismic data, where gas-hydrates were later recovered by drilling and coring (Sain and Gupta, 2008).
Led a seismic cruise by designing a specific experiment using state-of-the-art acquisition system, and delineated new potential zones of gas-hydrates in KG and Mahanadi basins through processing and modeling of 7500 lkm of high-quality multi-channel and 440 lkm of ocean bottom seismic data (Sain et al., 2012).
Organized an International Workshop in India on the topic "Science & Technology of Gas Hydrates: When can they be produced efficiently and safely" that provides a glimpse of views/concerns often asked by people (Sain et al., 2015).

Fig.1: Summary of entire gas-hydrates activities. Left - The most prospective zones (Krishna-Godavari, Mahanadi and Andaman) and less-explored but potential zones (Kerala-Konkan, Saurashtra, Kerala-Laccadive and Cauvery) of gas hydrates superimposed on gas-hydrates stability thickness map along the Indian shelf with the EEZ boundary. Middle - Seismic section showing BSR, marker for gas-hydrates with recovered gas-hydrates samples at right-bottom corner. Right - Sonic log and estimated saturation of gas-hydrates as a function of depth

Scientific Contribution to Sub-basalt Imaging in India

Since the era of exploring easy oil/gas is almost over, the industry looks forward for the exploration of hydrocarbons in sub-basalt Mesozoic sediments where more than 50% of the global oil has been found. However, a vast tract of western India (both onshore & offshore) has been covered by high-velocity Deccan Flood Basalt (DFB) or that has made conventional near-vertical reflection technique incapable of probing low-velocity Mesozoics underneath due to inherent limitations. We have provided a solution to this industry-challenge by wide-angle seismic experiment, and delineated large-scale velocity structure in the Kutch, Saurashtra and Tapti basins using wide-angle seismic traveltime tomography (Sain & Kaila, 1996; Sain et al., 2002a; 2004; Rao et al., 2004; Sridhar et al., 2009; Prasad et al., 2013; Murty et al., 2016). We have also delineated sub-volcanic Gondwana sediments in the West Bengal and Mahanadi basins (Sain et al., 2002b; Murty et al., 2008). But these models lack in finer details or stratigraphic horizons of sediments, for which oil industries show much interests. It is the computationally intensive full-waveform inversion (FWI) that can exploit entire seismic data (traveltime, amplitude, frequency, phase etc) and provide still finer details (Sain et al., 2004). We have successfully demonstrated the application of FWI to field seismic data in Kerala-Konkan (KK) basin lying south of Mumbai offshore, the main oil-producing province of India, and is anticipated of having prospective Mesozoics below the DFB. We have procured the wide-angle ocean bottom seismic (OBS) data in KK offshore from ONGC, Mumbai, and delineated finer details (Fig.1) of Mesozoic sediments (LVZ), for the first time, sandwiched between the younger basalt and older basalt corresponding to an excellent data fit. From the experiments with theoretical and field data sets, we have observed that a very good starting model, preferably the traveltime tomography model, is required, and the inversion should be performed at a low frequency and subsequently to be switched over to higher frequencies.

Fig.1: FWI result at 16.0 Hz around Well-1 along a line in KK offshore with Mesozoic sediments (LVZ). 1-D extracted from 2-D FWI result matches reasonably with VSP data.