Novel Scalechem Programe for Monitoring and Enhancing Dissolution of Scale Deposits Near Wellbore

DOI : http://dx.doi.org/10.13005/msri/040204

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The phenomena of desalination processes of the waters containing a considerable amount of calcium occurs both in cases of the pressure-driven membrane and electro- membrane processes, and is usually referred to as membrane scaling. Formation of mineral scale deposits is undesirable in various industrial processes where water and water treatment are involved, such as cooling systems, boilers, heat exchangers, filtration, mineral processing, oil and gas production, and geothermal systems. Common water formed scales include calcium carbonate, calcium sulfate, and barium sulfate. Most of scale found in Egyptian oil reservoirs was formed by direct precipitation from the formation water in high temperature and salinity reservoirs (Gulf of Suez Area), or from chemical incompatibility between injection water and formation water. In this study, ScaleChem software and laboratory Jar-testing were applied to evaluate the scale tendency of two Egyptian oil reservoirs existed in Gulf of Suez area. The two reservoirs were characterized by high temperature of 90-127 oC, and high salinity of 100,000-230,000 ppm. The salinity of injected water was 35,000 ppm. Both of theoretical software and laboratory Jar-testing results were comparing using an ion chromatograph (IC). Results ensured that the scales formation of calcium carbonate, calcium sulfate, barium sulfate and strontium sulfate, and their relative quantities have been functions of pressure, temperature and mixing ratio. Validity of ScaleChem software results has been checked by conducting Jar test at reservoir conditions. The produced scales formed from the Jar test have been analyzed using X- ray diffraction (XRD) and their results have been compared with the output data of ScaleChem software. It have been found that an excellent agreement obtained between results of ScaleChem software and Jar test, in addition the results of Jar test have been founded to be in a good agreement with field observations.

Desalination, scale deposition; scale prediction; OLI system and ScaleChem program