Chemical Enhanced Oil Recovery Pilot Design for Heglig Main Field-Sudan.

Abstract

Chemical enhanced oil recovery (CEOR) is emerging as a vital method to increase recoverable oil from aging reservoirs. The previous studies in screening of EOR methods for the Sudanese oil fields show that Heglig Main oil field is suitable candidate for CEOR operation. The Stock Tank Oil Initial in Place (STOIIP) for this field is about 577.95 MMSTB where only 22.2 % was produced. The objective of this research is to design the CEOR pilot for Heglig Main oil field using Computer Modeling Group (CMG) software. The main objectives of the Pilot in general; are to ascertain the alteration in oil saturation, injectivity, chemical absorption, chemical breakthrough time etc for CEOR in the field, and to obtain pilot results in order to further refine the CEOR full-field model. There are a lot of advantages of pilot mode, it lower the cost by utilizing the existing wells, and also least production disturbance by selecting the poor/medium performing wells, it should have sufficient time to observe pilot response time by selecting well spacing of 200-350 m which can be considered as main factors to select pilot well area in order to conduct sector modeling and check the flooding behavior, continuity, predict the production performance and incremental oil recovery, as well as to predict CEOR response and breakthrough time. In this research Seven (7) scenarios of five spot pattern in sector model from Heglig main has been conducted by using CMG software and three cases have been selected to study the sensitivity analysis and optimization in order to choose the best case. The result shows that a combination of 0.4% Alkaline, 0.1% Surfactant, and 0.1% of Polymer (ASP) concentration can increase the recovery factor of Heglig main up to 43.54%.