Campos Basin Tertiary Reservoirs of Barracuda and Caratinga Fields: Development Strategy and Main Reservoir Management Issues

摘要

Barracuda and Caratinga fields, with 1.1 GBOE reserves, are one of the main deep-water discoveries of the late 80’s and early 90’s in Campos Basin, southeast of Brazil. At that time, as it is nowadays, the economic feasibility of deep-water development projects was very much dependent on the high productivity of the wells. In despite of the quite good petrophysical properties, the thickness of the reservoirs did not provide enough productivity to make such projects feasible. The horizontal wells technology came over to improve productivity indexes, making possible the development of these giant fields. The high quality of the seismic data would help the positioning and the geosteering of the horizontal wells. The reservoirs of the fields are sandstone turbidites and have quite distinct depositional styles and structural features. Hence, different well patterns and completion strategy were used for each one. The reserves will be produced by 32 wells and, to maintain the reservoir pressure, 22 water injection wells will be used. To reduce the reservoir uncertainty, a production anticipation project -Pilot Project- was planned. Eleven exploratory wells were completed on the main reservoir units and blocks. These would permit the observation of the reservoir behavior and the checking of the reservoirs hydraulic compartmentalization, once the development wells were drilled. At the end of the Drilling Phase, the results are honouring the project initial assumptions. The Original Oil in Place as well as the productivity / injectivity indexes were confirmed. The reservoir pressure dynamic data showed that the assumed hydraulic model to set the development plan was very close to the verified one, regarding the horizontal and vertical connectivities. This paper focuses on the key factors that enabled a successful project implementation and on the strategy used for the reservoir development of these deep-water offshore fields.