Rio do Bu oil field, Recôncavo Basin: development, production strategy, and analysis of production zone II (Candeias Formation/Gomo Member)

Abstract

Located in the far nartheastern part of the Recôncavo basin, the Rio do Bu oil field has been almost entirely delineated. Covering an area of 4 km², the field contains sixty-five drilled wells and 10.76 x 106 standard m³ of exploitable original Gil in place. Its main Gil accumulations are found in the reservoir sandstones of the Gomo member, Candeias formation. Primary exploitation of the field has advanced to where some zones are already quite depleted. A secondary recovery project will soon be implemented, with water injection programmed for the Gil zone. It is expected that this will boost the recovery factor from 18% to 30%. Available data indicate that the predominant natural production mechanism in these reservoirs is gas in solution. There is also evidence that gravitational segregation is an acting mechanism in the northern compartament of the field, where beds dip southeastward sharply (about 20⁰). Maps of productian zone II indicate that the finest-quality reservoirs are found along the main axes of the turbidite fan system, while quality decreases toward the edges of the fan. This mapping is intended to guide the final stage of field development and implementatian af the secondary recovery project; in canjunctian with production records, it should yield a better understanding of reservoir behavior (i.e., praduction mechanisms, well productivity, pressure distributian, and drainage areas), thereby making it possible to tailor production network and injectian design to external and internal heterogeneities.