2.2.4 WAG ratio
The WAG ratio is the relation ratio between the fixed volumes of slugs of the water and gas that are alternately injected to the formation. According to WU (2004), WAG ratio can be also defined as the ratio of the volume of water injected within the reservoir compared to the volume of injected gas. The WAG ratio is considered an important parameter in attaining the optimum percentage of recovery factor. However, the WAG ratio selection depends on the reservoir distribution of permeability. Therefore, studies showed that there is a …show more content…
According to WU (2004) two studies were made where they involve one project of WAG process at the early age of the reservoir development plan, and the other is after an obvious miscible injection at breakthrough. The conclusion of the studies was that both cases had almost the same breakthrough time with a low production rate period. The production of both cases starts picking up significantly. However, based on simulation results, the early WAG process case had a slightly higher cumulative oil recovery that the late WAG process and it only shows when the injection pore volume reaches 1.2. Therefore, WU recommends the early WAG injection project right in the beginning of the reservoir development phase, to obtain the maximum oil recovery and maintain the average reservoir