Enhanced oil recovery: Potential for oil production development in Fang oilfield, Thailand

Abstract Fang oilfield is a small onshore reservoir in Thailand containing oil with gravity ranging from 20-40 °API and viscosity of approximately 10-120 cp. The depth of this field is from 300-1,200 meters and the sand thickness is varied from of 1 to 7 meters. For over 60 years of natural production, the field has low oil recovery. The difficulty has been attributed to the unfavorable production. Waterflooding, a secondary recovery, has been studied and the results show that the recovery can increase 4-6%. However, the production can be enhanced more with the tertiary recovery methods or enhanced oil recovery (EOR) which are recommended to increase oil production in this challenging field. However, the proper technologies have not been studied for commercial production yet. These technologies can be thermal recovery, gas injection, microbial enhanced oil recovery and chemical methods. Therefore, it will be the objective of this work to review and screen the EOR method to fit well with oil production in Fang oilfield in order to increase oil production. From this EOR screening, the main results from this study reveal that chemical injection is more appropriate for this field than other techniques because of reservoir characteristics and reservoir fluids. Based on the types of oil and composition in the oil, adding alkaline solution and surfactant can improve oil recovery because they can reduce interfacial tension of oil and to make the mobility higher. On the other hand, for other techniques, thermal recovery can increase mobility because of wax formation but it has higher cost. CO 2 injection can increase more oil production. Nevertheless, the sources of CO 2 has less supply and is expensive. Now, microbial enhanced oil recovery is on the beginning state and can provide the good potential. Consequently, based on the revision and screening method, the chemical method provide the higher commercial potential and feasibility to enhance oil production in Fang oilfield and the result of this study can be applied to design the plan of oil production operation in the oilfield in the future.