Multifunctional Composition Based on Surfactants and a Complex of Buffer Systems to Enhance Oil Recovery of High-Viscosity Oil Deposits

Abstract

To enhance oil recovery of high-viscosity oil deposits in the temperature range of 20-210 °C, a multifunctional composition with adjustable viscosity and high oil-displacing ability has been developed based on surfactants, aluminum and ammonium salts, an adduct of inorganic acid, carbamide and polyol. High buffer capacity of the composition in a wide pH range, 2.5-10 units pH, is provided by a complex of buffer systems: in the acidic range of pH, 2.5-4.0, the system “polyolboric acid and its salt”, in the alkaline range of pH – anammonia-borate buffer system. The composition has a low interfacial tension, a prolonged reaction with carbonate rocks, prevents the precipitation of insoluble reaction products, and increases the permeability of reservoirs. The composition is both oil-displacing and flow-diverting, it provides an enhance in the oil recovery factor, both due to the increase in the displacement factor and the the reservoir sweep by waterflooding or thermal steam stimulation

Efficiency of maintaining reservoir pressure in oil wells during the development of carbonate reservoirs

“…Considering the fact that large volumes of injected water go to a water-bearing part of the formation, the solution of this task is almost impossible without geological and technological measures. High inhomogeneity, lenticular state and reservoir compartmentalization affected the rapid growth of water content in certain sections and the unevenness of reserve recovery [15][16].…”