Chevron and Pdvsa-Intevep jointly conducted an evaluation of improved oil recovery (IOR) opportunities for the Boscán field to increase oil recovery and to help maintain future production rate. The shallower, northern area of the field was the target of this evaluation. Based on process screening results of Phase I, steam injection, waterflooding, and diluent/solvent injection were selected for a more detailed evaluation in Phase II.
During Phase II, fine-grid, geological models were built for the northern part of the field. In addition, laboratory experiments were conducted to obtain necessary data. The geologic model and input data were first validated using primary production data from representative wells. Numerical simulation studies for steam injection and waterflooding were conducted on three different segments to capture geologic variability. Effects of operating conditions and important uncertainties of input parameters on production forecast were obtained.
Results show that IOR processes have significant upside oil recovery potential. However, considerably smaller well spacing (well spacing of 290-m or pattern spacing of 54-acre or less) will be needed for floods. Only cyclic process can work at current spacing. Steamflooding results in the highest recovery (up to 43% OOIP). Cyclic steaming provides opportunity for accelerated recovery prior to steamflooding. Laboratory diluent injection appears promising but needs further evaluation.