--> Abstract: Deep Gondwana Sediments of a Part of Krishna-Godavari Basin - A Potential and Prospective Area for Unconventional Gas Deposits, by Prasad V. Inupakutika, Negi S. Bharat, Saksena K. Amit, and Singh R. Ram; #90081 (2008)
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Deep Gondwana Sediments of a Part of Krishna-Godavari Basin - A Potential and Prospective Area for Previous HitUnconventionalNext Hit Gas Deposits

Prasad V. Inupakutika, Negi S. Bharat, Saksena K. Amit, and Singh R. Ram
Geochemistry, KDMIPE-ONGC, Dehradun, India

At present about 15% of the total gas production in USA is from Previous HitunconventionalNext Hit basin-centered (synclinal) gas Previous HitresourcesNext Hit. Basin Centered Gas Systems (BCGS) are large and wide synclinal accumulations of gas in deep abnormally pressured sequences. The paper presents geoscientific studies performed in Kavitam-Poduru High and surrounding area of Krishna-Godavari basin (India), which reveals several similarities with established BCG accumulations.

The Gondwana sediments comprising coal, carbonaceous shale and sandstone of Kommugudem (Permian) Formation is about 300-400m thick sequence that have undergone deeper burial varying from 2.8km in the flanks to a maximum of around 7km in different lows. It is identified to be an effective source rock for gas and condensate occurrences in Mandapeta as well as Mandapeta-West fields.

The results of 1-D basin modeling performed in the representative lows indicate that the Kommugudem (Permian) source rock has attained 98-99% kerogen transformation with critical moment corresponding to 50% transformation ratio (TR) at 110-80 Ma. The source rock units of Raghavapuram Shale (Early Cretaceous) have also attained kerogen transformation to the extent of 90% at the base with maturity of 1.5%VRo and TR: 12% at the top of the sequence.

The presence of continuous gas shows in a couple of deep wells, which penetrated the Mandapeta (Permo-Traissic) Formation indicate that the deep basinal lows may have conditions favorable for development of tight-gas sands as Basin Centered Gas Accumulations (BCGA) based on the evaluation of pressure data, shale density and sonic logs trends corroborating over-pressured sequences.

The probability of existence of the “sweet spots” in the Kavitam-Poduru high trend is likely because of the inversional features observed and large amounts of hydrocarbons generated from the Kommugudem source rocks .

Presentation GEO India Expo XXI, Noida, New Delhi, India Previous Hit2008Top©AAPG Search and Discovery