Abstract:
The Pattani Basin, Gulf of Thailand, is characterized by small, faulted, and vertically stacked fluvial reservoirs. The oil and gas reserves per well are small and are developed through low cost wells. Any additional investments, such as water injection pipelines and pumps are hard to justify. Water dump flood is proved technology, and it could be a viable IOR technique for small oil reservoirs. This study evaluates dump flooding in the Pattani Basin, Gulf of Thailand via finite difference numerical simulation and aims to identify parameters such the ratio of aquifer to reservoir size that yield successful dump flooding projects. This study evaluated the following scenarios: (1) comparing three wells producing under solution-gas drive mechanism against water dump flood from an edge well and a water dump flood from a center well, (2) comparing the performance of water dump flood as a function of the aquifer size, (3) evaluating the impact of well productivity index (PI) on the oil recovery for the water dump flood, (4) evaluating the impact of well injectivity index (II) on the oil recovery for the water dump flood, (5) studying viability and performance of water dump flood at reservoir depths of 4000, 6000, and 8000 ft TVDSS, (6) studying viability and performance of an underlying aquifer dump flooding, (7). Simulating more cases by changing oil gravity, and (8) performing simulation runs to study the optimal depletion point to begin the water dump flooding. The study found that dump flooding can increase the recovery factor up to 12 percent depending on the choice of well location and aquifer to reservoir size. The results of the study suggest that the best well locations are edge wells. The study suggests that there is an optimal aquifer to reservoir ratio around 43 RBL/RBL that maximizes oil recovery factor. Finally, the oil recovery efficiency for all different times to start water dump flood is higher than no water dump flood.
