Smart water flooding: An economic evaluation and optimization

Smart water (or low salinity water) flooding has been an emerging technology in the petroleum industry since last two decades. Low capital cost and operating expenses of this flooding make it attractive for the petroleum industry. This paper examines the economic feasibility of the injection of smart water and compares with other conventional water flooding techniques. Optimization has also been done with different dilution schemes through particle swarm optimization. This study analyzes the effect of smart water and sequential dilution of injected sea water through reservoir modeling. A three-dimensional black oil reservoir model is developed by using ECLIPSE 100. In addition, this study presents the economic feasibility of the injection of smart water and compares with other conventional water flooding techniques. The study is divided into four cases: i) oil is produced without water flooding, ii) formation water is injected in the reservoir, iii) sea water is injected in the reservoir, and iv) water injection is taken place by sequential dilution of high salinity water. In each case, economic evaluation is completed by calculating the costs and revenues generated by water injection, and oil prod uction. The results show that sea water injection did not give additional oil recovery compared to formation water injection for our case. However, additional results show that sequential dilution flood recovers more oil than sea water and formation water injection. Moreover, five main parameters are optimized such as number of cycles of different salinities, duration of various cycles, salinity values for different cycles, injection rate and production rate. Optimization results show even better results than sequential dilution. The optimization also shows that the additional oil recovery is achieved when the dilution sequence is altered. This outcome illustrates that increased oil recovery is not only dependent on step wise reduction of sea water salinity but also with the variation of dilution pattern. This paper presents a novel technique for the reservoir engineers to study smart water flooding with different perspective. Sequential dilution has been an acceptable technique for increasing oil recovery. However, change of the dilution pattern could be a good alternative and thus provides a cost-effective technique as compared to sequential dilution.