The Reservoir Simulation of Oil Production using Enhanced Oil Recovery Technologies: Carbon Dioxide Injection, Water Altering Gas Injection and Nitrogen Injection in Cornea Field, Western Australia / Nurafiqah Binti Abdullah @ Chai Yew Tin

A thesis submitted in fulfillment of the requirements for the Degree of Doctor of Philosophy.

Abstract

The Cornea field on the Yampi Shelf of the North-Eastern Browse Basin, offshore Western Australia, was studied. There was a significant amount of hydrocarbon in the Cornea field with oil and gas samples; however, this reservoir field's productivity has not been proven. In addition, one of the challenges of deploying new technology completions to tackle the technical challenges presented by reservoir characteristics to extract and recover oil from this field must be overcome for the Cornea field to become commercially viable. Therefore, improvements in production techniques are essential in this field. Hence, this research is mainly focusing on filling the gap present from the previous study. The study aims to simulate advanced technologies in this field by simulating the Cornea field with CO, injection, water alternating gas (WAG) injection and N₂ injection, comparing oil production obtained from these simulated methods and determining the optimum simulated method in this field. The 3D model was constructed in PETREL software using the data obtained. Since faults are present surrounding this field, a fault model was constructed, and sensitivity analyses were conducted for investigation purposes only by varying fault permeability and fault displacement to thickness ratio to test the uncertainty in transmissibility. It shows that fault permeability at 100 mD and fault displacement thickness ratio 170 resulted in higher fault transmissibility. PVTi and ECLIPSE software were used for numerical simulation of CO₂, WAG and N₂ injections. The model comparing Minimum Miscibility Pressure (MMP) obtained from the simulation result with the MMP correlation method was validated. CO₂ injection reached its miscibility at 36.5 Bar while N₂ injection reached its miscibility at MMP above 27 Bar. The sensitivity analyses varying CO₂ and N₂ reservoir pressure, reservoir temperature and injection rate conducted. WAG ratios, WAG cycle time, and the first phase to be injected variable were also tested. From the result, it shows that N₂ injection is a more feasible method to be implemented in this field since it produces the highest cumulative oil production compared to CO₂ and WAG injections with lower miscibility pressure at 27 Bar and injection rate at 600 sm³/day. In addition, it is a cheaper method when compared with CO₂ injection and WAG injection.