SUBSTANTIATION OF SELECTIVITY OF GEL-FORMING COMPOSITION DURING WATER-SHUT TREATMENT IN RESERVOIR OF FRACTURED-POROUS TYPE

Abstract

The article is devoted to one of the main problems of oil production industry – high level of watering. Several methods of water control are investigated, but the accent is made on selective methods and materials, that increase filtration resistance in water-saturated part of a layer. Water shutoff agent based on sodium silicate is developed for selective restraining of water inflow in fractured-porous reservoir. Laboratory research of the developed gelling agent helped to establish interdependence of gel strength and period of gellation between agent concentration and temperature. It is revealed, that addition of polyatomic spirit in water shutoff agent leads to the increase of hydrophilicity if related to water-saturated rock and decrease of hydrophilicity if related to oil-saturated rock. Furthermore, high wettability of the waterproof agent in relation to water-saturated rock in comparison with oil-saturated rock proves the selective characteristic of the developed agent – when the plugging material gets to the water-saturated part it makes firm insulating barrier due to better contact with rock. Besides the change of wettability the addition of polyatomic spirit in water shutoff agent improves operational characteristic of developed plugging material in account of increasing of interionic forces and expands the exploitation temperature range. The filtration tests proved the effective influence of inorganic gel on core sample of fractured porous reservoir from the eastern part of Orenburg oil-gas-condensate field. Also, permeability of water-saturated core samples decreases better than of oil-saturated ones. This fact proves the selectivity of the developed agent.