Divalent metals cations present in injection\r\nwater can significantly influence the performance of alkaliââ?¬â??\r\nsurfactantââ?¬â??polymer (ASP) flooding. These cations such as\r\ncalcium and magnesium react with the added chemicals to\r\nform their insoluble salts as precipitations. In this paper, an\r\nin situ precipitation inhibitor known as sodium acrylate is\r\nused to overcome the precipitation problems prevalent with\r\nASP flooding. Fluidââ?¬â??fluid compatibility tests were performed\r\nto examine the performance of the in situ precipitation\r\ninhibitor using hard brine having large quantity of\r\ndivalent metal cations. The effect of the precipitation\r\ninhibitor on interfacial tension was also investigated using\r\nvarious inhibitor concentrations. The in situ precipitation\r\ninhibitor showed an excellent performance in preventing\r\ncalcium and magnesium precipitations and the solutions\r\nremained clear for 45 days at 80 C. Further, as the\r\ninhibitor concentration increased to an optimal value, an\r\nultra-low interfacial tension of 0.04 mN/m could be\r\nachieved. The advantage of the in situ inhibitor is the use of\r\nhard brines without the need for softening the injection\r\nwater.
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