Master of Science (MS)
Surfactants have a variety of applications in the petroleum industry due to their remarkable ability to lower the oil-water interfacial tension and alter wettability. However, surfactant adsorption on rock surfaces has severely crippled this means of improving oil recovery due to the high cost associated with the large quantities of surfactant needed. A previous experimental study by Ayirala (2002) reported the development of mixed wettability using a nonionic surfactant. At this mixed-wet state he was able to recover about 94% of the original oil in place. The underlying motivation of this study was to achieve such high recoveries without using large quantities of surfactants. A new surfactant enhanced waterflood method is proposed as the means to accomplish this task. This improved waterflood method consists of soaking the area around the production or injection well with an optimally concentrated surfactant slug prior to conducting a waterflood. Four variations of this novel process were investigated. The first two variations examined two surfactant slug sizes (0.2PV and 0.3PV) soaked around the production well prior to conducting a waterflood. The third variation explored the idea of soaking the area around the injection well instead of the production well prior to a waterflood. After soaking the area around the production well with a surfactant slug, the fourth variation used a low concentration (LC) surfactant solution to flood the reservoir instead of water. The main objective of this study was to evaluate whether these proposed improved waterflood methods are technically feasible, and also determine their effectiveness when compared to a conventional waterflood. In addition, simple cost analysis calculations were carried out to show the economic feasibility of the proposed improved waterflood variations, especially when compared to a conventional waterflood. All the experiments utilized the same rock and fluid properties, as those used by Ayirala in his coreflood experiments. A surfactant (Tomadol™ 91-8) with similar properties and recovery to that used by Ayirala was used in this project. This project was divided in four sets of experiments. This study found that all four improved waterflooding variations were technically feasible, and were more effective in improving oil recovery than a conventional waterflood. In addition, the proposed improved waterflood variations accomplished the task of significantly improving oil recovery with small quantities of surfactant.
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Mwangi, Paulina Metili, "An experimental study of surfactant enhanced waterflooding" (2010). LSU Master's Theses. 2021.
Rao, Dandina N.