Simulation and Economic Screening of Improved Oil Recovery Methods with Emphasis on Injection Profile Control Including Waterflooding, Polymer Flooding and a Thermally Activated Deep Diverting Gel

Abstract

Abstract The large volumes of water produced during oil extraction presents a significant problem due to the high cost of handling and disposal in an environmentally friendly manner. On average, an estimated seven barrels of water is produced per barrel of oil in the US, and the associated treatment and disposal cost is an estimated $5-10 billion annually. Water production can be particularly problematic during waterflooding in highly heterogeneous reservoirs with vertical communication between layers leading to unevenness in the flood front, cross-flow between high and low permeability layers and early water breakthrough from high permeability layers. Some of the different technologies that can be used to counteract this involve reducing the mobility of water or using a permeability block in the higher permeability, swept zones. Selective permeability blockage, however, is particularly difficult where crossflow is possible. This research was initiated to evaluate the potential effectiveness of an approach to the latter method, known as deep diverting gels (DDG) to plug thief zones deep within the reservoir and far from the injection well. To evaluate the performance of DDG, its injection and placement was modeled, sensitivities run for a range of reservoir characteristics and conditions and a rudimentary economic analysis was performed. Performance of the DDG is compared to waterflooding and polymer flooding from a technical and economic perspective. A literature review was performed on the background of injection profile control methods, their respective designs and technical capabilities. Commercial software was used to simulate the behavior of these methods in a reservoir using simplified assumptions of reservoir characteristics and fluid properties. Simulation results were used to carry out economic analyses of the recovery methods. Results show that the largest impact on economics was incremental oil produced. Polymer flooding had the highest NPV in all case comparisons followed by DDG.