Abstract

The divers silicate technologies have been used more than 120 times in Hungary, Germany, Serbia and Oman for reservoir conformance improvements including water shut-off and profile correction in oil and gas wells, restriction of gas conning in oil reservoirs, blocking of gas leakage in gas storage and restriction of CO2 migration in a collapsed well. The advanced methods based on simultaneous application of polymers, urea, humates, etc. recognizing that the pure silicate gels have disadvantageous properties under reservoir conditions. The present efforts were focused on replacement of some additives in gel-forming solutions; meanwhile the efficiency of the method remained the same or even better under various formation conditions. Based on earlier results, it was proved that addition of water-soluble polymers to silicates improved significantly the stability and flexibility of such gels. Beside the beneficial effects, however, the polymer-containing silicate solutions may also have some drawbacks to placement and in-situ dispersion of treating fluids. These difficulties can be eliminated by replacing polymers with nanomaterials. The detailed laboratory studies focused on polymer free, but SiO2 and Al2O3 nanoparticle containing silicate solutions. Results of laboratory study of gelation mechanism, rheological properties, flow behavior, and nanoparticle sizing served to draw fundamental conclusions. It has been shown that these nanomaterials can replace completely the polymers, they are compatible with even low permeability porous, and fractured media, and less pH-controlling agent is necessary to catalyze gelation.

Recently, the efficient and flexible silicate technologies arouse high interest in oil and gas production. Their environment friendly solutions are particularly appreciated. Replacing the often-questionable synthetic polymers in gel-forming solutions with nanomaterials is the final step toward to use harmless chemicals in absolute sense. Based on the laboratory tests the silicate/nonmaterial method was tailored to oil producers operating in the largest Hungarian oil field. The pilot tests will be carried out in 2013. Combining silicates and nanomaterials, new and efficient method was developed for water shutoff and profile correction in various oil and gas fields and that may open new vistas in improvement of well performance of both producers and injectors.

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