A Comparative Simulation Study of WAG and Surfactant EOR Methods Applied to Norne field E Segment

Abstract

The production of oil by primary and secondary recovery methods can only recover up to 35% of originally oil in place, that means 65% of oil remains trapped in the reservoir, therefore there is the need to research for more advanced ways on how we can improve the recovery efficiency especially in the depleting reservoir through suitable enhanced oil recovery (EOR) methods such as Water Alternating Gas (WAG) injection, Surfactant Flooding, and other chemical EOR methods.

Norne E-segment is in the decline phase and is facing major challenges concerning the amount of the oil by-passed due to water flooding. Water flooding alone cannot recover most of the oil in the reservoir, thus it requires the application of EOR techniques that would reduce residual oil saturation to minimum. Two EOR techniques such as Water Alternating Gas (WAG) and Surfactant Flooding were simulated for the Norne E-segment.

The main objective of this study was to do a comparative simulation study of Water Alternating Gas (WAG) and Surfactant Flooding in the Norne E-segment to evaluate the effectiveness of these two EOR techniques compared to conventional water flooding in terms of incremental oil recovery (IOR). At the end of the simulations, one of the EOR techniques was to be chosen for the Norne E-segment based on the incremental oil recovery.

Based on the simulation results, WAG injection was found to be better than surfactant flooding in terms of incremental oil recovery. The incremental oil recovery for WAG injection was 3.3% over the conventional water flooding and that for surfactant flooding was 1.7% over the conventional water flooding. Finally, it was recommended to find out the right surfactant structure that would be compatible with fluid and rock properties of the Norne E-segment.