ABSTRACT

The most important Brazilian deep water reservoirs are located in the Campos Basin, at present day water depths ranging between 600 and 2,600 m. All of these reservoirs are turbidites of Upper Cretaceous to Miocene age.

The Tertiary reservoirs are poorly consolidated sandstones with very high porosity and permeability, which contain oil with density between 16 and 25°API. The Cretaceous reservoirs are better consolidated, with good porosity and permeability and containing oil with density of about 30°API. The deep water reservoirs are usually large, day free, have good continuity and are drained by high productivity wells. Sand production control is usually required.

Following a new discovery, a multidisciplinary team starts to work in an integrated way to optimize the project Seismic analysis has shown to be a very important tool for mapping and for helping to reduce the number of appraisal wells. Early production with a “mini project” is usually planned to obtaining reservoir behavior and production operation information.

For giant fields, the development project is divided into phases or modules, which permits a decrease in risk, distribution of investments over time and development of the appropriate technology for the field. Well spacing is usually large and horizontal wells have been preferred in order to increase productivity and reduce the number of wells. Water injection is used for improved oil recovery (IOR), because of low cost and good recovery efficiency. The maximum recovery efficiencies range from 15% to 40%, depending basically on the oil viscosity.

The main deep water production challenges are drilling and completion of non-conventional wells, IOR methods, 4-D seismic for monitoring water-oil system, subsea pumping and boosting, and production at water depths around 2,000 in by the year 2000.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah