Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

A. K. Dwivedi ¹, A. K. Bajpai ¹, H. C. Srivastava ², R. K. Thakur ¹, N. K. Lal ¹

Affiliations
1 KDM Institute of Petroleum Exploration, ONGC Ltd. Dehradun, IN
2 Geo-Science Division, ONGC Ltd. Jorhat, IN

Abstract

The use of seismics to recognise and map stratigraphic traps is becoming an important phase of exploration activity in mature hydrocarbon provinces, world over. The stratigraphic wedge-outs have provided excellent trapping mechanism in some of the giant fields of the world. Surat depression is known to be the main kitchen for the hydrocarbon occurrences in Bombay High and around. Commercial accumulations have been encountered in Mid-Tapti and South Tapti fields of Surat depression. These accumulations are in structural traps. However, further updip, over Saurashtra shelf, the exploratory efforts have remained limited due to the absence of any structural prospects, The present paper deals with the interpretation of close grid seismic data with an objective to: i) identify seismic sequences and the depositional environments and ii) to map stratigraphic trap at levels equivalent to Eocene sands with oil indications encountered in the earlier drilled exploratory wells.

Keywords

Surat Depression, Sequence Analysis, Seismic Markers, Bombay Offshore.

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N. K. Lal ¹, A. Siawal ², Anil K. Kaul ²

Affiliations
1 310, Lane 9, Mohit Nagar, Dehradun - 248 001, IN
2 KDMIPE, Oil and Natural Gas Corporation Ltd., Dehradun – 248 195, IN

Abstract

The evolution of east coast of India is discussed within the ambit of clearly identifiable four major tectonic stages which had a profound effect in shaping the tectonic grain of the east coast basins. The evolutionary process began with rift related crustal extension between India and Sri Lanka as a consequence of Africa-Antarctica rifting and development of Natal Basin. An arm of this rift led to initial extension in the Cauvery Basin and failed. Later, the IndiaWest Australia rift propagated further in southwesterly direction initiating Mahanadi and Krishna-Godavari Basins. This extension was an oblique one with Nayudupeta high acting as pivot. The oblique extension followed by asymmetric seafloor spreading developed transpression along India-Sri Lanka and Antarctica junction, resulting in a NNW-SSE trending transcurrent fault along which Antarctica moved southward. Subsequently, entire east coast evolved through a more or less uniform post rift stage.

Keywords

Plate Tectonic Reconstruction, Transcurrent Fault, East Coast of India.

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