Modeling and Simulation of Smart Gels for Conformance Improvement in Waterflooding

Abstract

Recent studies have shown that enhanced oil recovery will be the focal point for approximately 50% of the global oil production in the upcoming two-three decades. According to the several ballpark studies conducted on EOR techniques, results show that for reservoirs with oil viscosities ranging from 10 to 150 m Pa.s., polymer flooding seems to be an ideal development strategy. However, when the oil viscosities exceed 150 m Pa.s., polymer injectivity and pumping efficiencies can turn out to be major inhibiting factors, thereby limiting the range of oil viscosities for which polymer flooding can be utilized. The core reason for this is that the values of viscosity for the injected water containing polymer, calculated for the beneficial mobility ratio, can lead to the inhibiting factor stated above. Previously conducted lab studies have shown that supramolecular systems are very resistant in high temperature - high salinity systems. To be able to achieve the easier injection, the injected supramolecular viscosity will be kept at lower values and then increased to the levels right before or upon contacting the oil in the reservoir. The core difference between conventional polymer systems and supramolecular polymer systems is that the latter disassemble and re-assemble as opposed to degradation when exposed to extreme shear stress and temperatures. It can therefore be said that supramolecular polymer systems are self-healing in nature. The phenomenon has been observed in cases where polymers with high molecular weight are forced through narrow flow channels. Though molecular division takes place, supramolecular systems have shown a tendency of reassembly later on. Therefore, adaptability of these systems to bounded or restricted environments can be established. This study will add the modeling and simulation components of supramolecular systems which can be effectively utilized in high temperature-high salinity conditions through adjustments to viscosities and interfacial properties of these assemblies. This will help compare the displacement efficiency of supramolecular systems which efficiently perform in a wide range of reservoirs such as thin zones, and reservoirs within permafrost conditions. This can significantly benefit the oil and gas companies worldwide in preparing a technically feasible, but also, a cost effective EOR development strategy, whenever polymer injection is of consideration.

Review on Microemulsions for Conformance Improvement Technology: Fundamentals, Design Considerations, and Perspectives

“…Initially, Winsor I formation is favored at very low salt concentrations. However, as the salt content increases gradually, surfactants form strengthened “direct + reverse” micelles to form MEs above a certain salinity level known as the “lower critical salinity limit”, which induces a state of equilibrium between oleic and aqueous phases. , This phase behavior, referred to as Winsor III, persists until the “upper critical salinity limit” is reached . Beyond this limit, hydrophobicity of surfactant/emulsifier molecules increases and the surfactant tends to diffuse into the oleic phase, resulting in the formation of Winsor II.…”

“…90,91 This phase behavior, referred to as Winsor III, persists until the "upper critical salinity limit" is reached. 90 Beyond this limit, hydrophobicity of surfactant/emulsifier molecules increases and the surfactant tends to diffuse into the oleic phase, resulting in the formation of Winsor II. Salts result in the "thinning" and partitioning effect of the electrical double layer at the oil−water interface, which alters the intermicellar distribution of direct/reverse micelles in the microemulsion phase.…”

“…ME composition must be chosen depending upon the temperature profile of the producing zone. In comparison to conventional polymers and foams, which are sensitive to a high temperature, MEs retain their structural integrity under varying conditions of temperature and pressure within a desirable range. , High-temperature conditions may influence the stability of conformance control fluids to operate for long-term projects. , …”

Benefits of the Tracers Test Technique in Improving the Performance of Group Wells

“…Thrasher et al (2016) stated that the high reservoir heterogeneity generally restricts the execution of water-flood. This process is known as the conformance problem, and it affects the poor volumetric sweep efficiency of a conventional water flood (Temizel et al, 2018).…”