Integrated Geoscience and 4D Technology Defines Reservoir Compartments to Extend Production Life of the Ravva Field, K-G Basin, India

McClenaghan, Ray; Saika, Kausik; Mishra, Susanta; Rao, Challapalli; Reddy, Kondal; Gupta, Menal; Guttormsen, Joel; Joysula, Sivasankar; Burley, Stuart D.
Subsurface, Cairn Energy India, Gurgaon, India.

The Cairn India operated Ravva Field is located offshore of the Godavari Delta, within the KG Basin, on the east coast of India. Oil and gas reserves were discovered in 1987 by the well R-1, which penetrated the then proposed middle Miocene turbidite sandstones. These Miocene sandstones have been deposited in a NW-SE oriented wave dominated, lower to upper shoreface setting. During the Pliocene to recent times the basin underwent several episodes of tectonic movement which has re-activated pre-existing faults. Several tilted and rollover fault blocks provide the trapping mechanism in the field. The exceptional quality Miocene reservoirs, comprising high porosity and multi-darcy sands, are sealed by overlying early Pliocene shales.

Within the initial phase of field development all litho-biostratigraphic, bore hole image together with strati-structral dip data have provided the opportunity to construct the depositional and palaeogeographic model, reflecting a depositional setting of a wave dominated deltaic environment. Reservoir management is via a series of up-dip producer wells with pressure maintenance from associated injectors. Exploitation of the field was undertaken based on extensive simulation studies and an on-going dynamic reservoir surveillance program (comprising production logging, reservoir saturation monitoring, tracer injection) to ensure that reservoir performance is optimised. The Ravva Field JV commitment to excellence in reservoir management is evident in the production performance of the field. Plateau production has been extended, and current 4D results, when incorporated with new reservoir characterisation studies described here, will be instrumental in future well planning and extending field life. To date Cairn India and partners have produced in excess of 200 mm bbls from the Ravva Field.

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012