| Gel placement within fractured zones of the reservoir is a technique that has been employed to decrease water production. In order to utilize this technique more effectively, the technique of gel placement and its performance within fractures must be established.; Previous experiments have shown that Cr3+ ions diffused from the gelant placed within the fracture to the brine residing in the adjoining matrix. As a result, insufficient crosslinker was available for the formation of a stable gel. It was concluded that gelants could only form stable gels if they were placed with forced gelant leak-off into the matrix, or if they were injected in the form of matured gel.; In this study, fractured Berea sandstone slabs are used to create a fractured system. In order to obtain a stable gel in the fracture without gelant leak-off, two techniques are studied. Firstly, a technique by which the chromium concentration in the gelant is overloaded (polymer concentration remaining the same) is proposed and investigated as to whether a stable gel could be formed. Results show that significant gelation occurs upon increasing the chromium concentration from 2 to 5 times the initial concentration (polymer concentration remains the same) and significant permeability reduction occurs. Gelants with 5 times the chromium concentration resisted gel washout. (Abstract shortened by UMI.)... |
