Preparation and comprehensive performance evaluation of a temperature and salt-resistant gel system

Abstract

With the global development of oil and gas resources extending to deeper and more complex strata, high-temperature and high-salinity heterogeneous oil reservoirs have become an important area for increasing reserves and production. This type of oil reservoirs generally confront two core challenges: First, the high formation temperature and salinity cause traditional polymer gels to experience problems such as sudden strength drop and dehydration shrinkage due to thermal degradation of molecular chains and ion shielding effect. Second, the strong heterogeneity with permeability contrast greater than 10 leads to the bypassing of displacement fluid through high-permeability channels, resulting in the utilization rate of crude oil in low-permeability areas being less than 40%. The recovery rate of such reservoirs is 15-30% lower than that of homogeneous reservoirs, resulting in an annual production loss exceeding 10 million tons.Although existing chromium/aldehyde crosslinking systems exhibit certain temperature resistance, their green application is constrained by heavy metal pollution risks and the toxicity of aldehydes, necessitating the urgent development of environmentally friendly intelligent plugging and regulating materials. In recent years, organic-inorganic hybrid gels have become a research hotspot due to their designability, but their long-term stability under extreme conditions remains a bottleneck.