Reservoir Characterization & up Dip Darin-Hole Modeling for Improved Oil Recovery from Depleted L-III Reservoir; A Case Study of Mumbai High - Oil Field, India

Vijay K. Singh
Western Offshore Basin, O.N.G.C. Ltd, Mumbai, India

The Mumbai High field has been divided into two different block of separate hydrocarbon system, Mumbai High -North and Mumbai High -South based on gas-oil and oil -water contact, occurring at different level for the L-III reservoir.

Mumbai High - North field was put on production in 1976 and oil production gradually increased to a peak rate in 1982-84 by the initial field development.A peripheral water flood was initiated in 1984. In Mumbai High - South field, the development of L-III reservoir started in 1980 and the field produced oil at its peak rate during 1984 to 1991. A peripheral water injection started in March 1987 and followed by central and up-dip injectors.

By the end of nineties, the production from L-III reservoir has shown its declined trend, and re-development was needed to meet the domestic target of oil production. Re-development of feild started in 2000, by drilling more ERD, LDST/SDST wells with 6" drain-hole to enhance oil production from L-III reservoir. By end of 2004, 106 re-developments wells drilled in Mumbai High & oil production increases from 218,000 barrel per day to 270,000 barrel per day.

But, many wells showed negative reservoir behavior and produced more water cut within six month of its completion. Under this assumption that, the field has depleted and water cut is not unforeseen, is not the correct answer.

The present study is to bring out probable reason for such type of reservoir behavior, conjunction with well placement, reservoir characteristic and drain-hole modeling in Mumbai-High.

Under this preview, the basic field/well data of some successful re-development wells of Mumbai - High, were analyzed under the light of Hydrodynamic, Phase-behavior of reservoir and flow modeling. And, it is concluded that, the drilling of Up- dip drain hole model in is better option to improve oil recovery from sub-layer of L-III reservoir.

Presentation GEO India Expo XXI, Noida, New Delhi, India 2008©AAPG Search and Discovery