Cyclic Same-Well Enhanced Oil Recovery - Gas EOR Assessment for a Horizontal Multi-Fractured Well

Abstract

Demand for petroleum hydrocarbons in the world is still high but the proven conventional reserves has decreased progressively. Alternative power resource in the form of unconventional reservoir eventually has become a prime target for development. Since numerous challenges are encountered in this resource s development, many ways to improve oil recovery have also been performed. Nowadays, shale oil reservoir as one of unconventional resource gains much attention in the oil industry. The common technique used to produce shale oil reservoir is by occupying stimulated horizontal well with hydraulic fracturing optimization. However, the capability produced by this existing method is still very small, with final oil recovery factor generally in the range of only a few percent. However, many challenges are faced associated with more expensive development costs and low world oil prices which make the exploitation and learning curve for this reservoir was very slow. Optimum development strategy by maximizing oil recovery and minimizing the investment cost is urgently required to overcome current challenges. This study addressed the key importance of implementing EOR gas injection to shale oil reservoir. Then, its implementation by using the principles make the most out of what we have was proposed and studied in every aspect. Cyclic gas injection strategy is the development idea for improving recovery and minimizing operating cost, which are the main focus to be evaluated in this study. In the research, this study used numerical simulator to predict the performance. The analysis showed that the cyclic gas injection EOR has very good potential to be applied in shale oil reservoir. Sensitivity study against various uncertain environment as well as technical operating scenario were examined in this study. Range of typical value of these parameters were systematically investigated. It is shown that the higher improvement to connectivity between fractures result in higher oil recovery factor. It was also observed that the lower cycle time gives promising oil recovery, although there is an optimum value which will incorporate the needs of improving oil recovery as well as controlling the gas injection efficiency. Monte Carlo simulation to assess the more reliable probability was also performed to further assure this strategy. From all simulated cases, it was shown that the implementation of same-well cyclic injection strategy is highly recommended to be applied in shale oil reservoir.