Abstract

Drilling new / side track wells into a depleted reservoir is a challenge. Many times, total mud losses are encountered and this combined with shale swelling makes the well bore extremely unstable and prone to failure. Such operational problems warrant the immediate lowering of casing liners with out recording open hole logs. This is the case with Mumbai High carbonate reservoir which is one of the biggest Middle Miocene hydrocarbon reservoirs in India. The Mumbai High field which is on production since 1976 has been producing oil from this multi-layered reservoir. Each layer of the limestone is encapsulated in shale/Marl. Logging after casing lowering brings the possibilities of evaluating the formation with out jeopardizing the stability of the well bore.