Abstract: Prospecting and Developing Carbonate Reservoirs Under Excessive Pressures in Fields of PreCaspian Depression Taken as an Example

Ray Leonard, Vasily Perepelichenko, Anatoly Shilin

All large sub-salt hydrocarbon fields of the PreCaspian depression are connected with carbonate reservoirs and are characterized by abnormally high reservoir pressures of different origin.

Exploratory drilling in fields under excessive pressures is very much complicated. To reduce the probability of disastrous absorptions and blowouts there has been developed special drilling-in technology with constant bottom-hole pressure control.

To avoid fractures healing, to provide hydrocarbon phase state control, and to achieve maximum oil recovery there has been worked out a new technology of oil field development. According to this technology oil should be recovered first from the lower peripheral parts of the pool. This technology (taking into account the abnormally high reservoir pressures) provides gradual decreasing of reservoir pressure in the process of field development.

AAPG Search and Discovery Article #90951©1996 AAPG International Conference and Exhibition, Caracas, Venezuela