纳米SiO2颗粒改善凝胶体系调堵性能室内研究OA

To effectively enhance the plugging effect of gel systems in high-permeability channels and their long-term stability in formations,a nano-SiO2-reinforced composite gel system was prepared using partially hydrolyzed polyacrylamide as the main agent,phenolic resin as the crosslinker,and modified nano-SiO2 as the stabilizer and reinforcing agent.This system exhibited shear resistance,high viscoelasticity,and high strength.The performance of the composite gel system,including its solution properties,plugging efficiency,and injection-production characteristics,was studied by using a rheometer and the experimental equipment for multi-dimensional physical simulation.Compared with conventional gel systems,the nano-SiO2-reinforced composite gel showed improvements in gel strength by 20%-50%,elastic modulus by 50%-150%,viscous modulus by 40%-80%,and shear resistance by 15%-20%.Physical simulation experiments demonstrated that the nano-SiO2-reinforced composite gel effectively could plug high-permeability layers and mobilize low-permeability layers,reducing the fractional flow rate in high-permeability layers from 98.3%to 2.5%and increasing the fractional flow rate in low-permeability layers from 1.7%to 97.5%,achieving a profile improvement rate of 96.8%.Under the conditions of a four-fold permeability contrast in a three-layer heterogeneous core,the oil recovery was increased by 6.9%,indicative of the effectively enhanced mobilization of medium-and low-permeability layers.The nano-SiO2-reinforced composite gel system could provide significant guidance for improving oil recovery in reservoirs with high-permeability channels.