October field is a large oil field located in North Gulf of Suez (N-GoS) of Egypt. The reservoir was discovered in the mid-1980s. More than 20 wells have been drilled in the reservoir, revealing considerable complexity and heterogeneity. Until late 1999, the production mechanism was natural depletion above bubble point. At that time water injection was started and has since been extended to all the field.
Based on pressure performance data, the reservoir could be divided into five relatively independent producing areas. In initial field development, material balance techniques were used to evaluate group "5" performance. Using graphical techniques, a dynamic STOIIP close to the mapped STOIIP was obtained. However, due to reservoir heterogeneity, material balance techniques were not adequate for providing reliable predictions under water injection.
A reservoir model that could accurately predict future production had to include reservoir heterogeneity. Within an integrated subsurface team environment, a geological static model was constructed and a numerical reservoir simulation study was performed.
This model led the team to conclude that this area was affected by water injection wells in the adjacent block and that the current reservoir pressure could be about 400 psi higher than previously expected. As a result, an immediate static survey was run that confirmed the simulation results. A recommendation was made to return previously shut-in wells to production resulting in an oil gain of 1,500 BOPD.