Preparation and Performance Evaluation of Alkali-resistant Gel-type Deep Profile Agent

Currently, most profile control agents would be degraded in strong alkaline condition. They could not be applied in ASP (alkaline, surfactant and partially hydrolyzed polyacrylamide) flooding. To solve this problem, a new kind of alkali-resistant gel for deep profile has been studied. Based on the profile control mechanism of profile agent and the crosslinking mechanism of the polymer, the selection of the chemical agent with different type and concentration was carried out in strong alkaline (pH=12), using ordinary polymer as the main agent, organic and inorganic chemical crosslinking agent. The performance evaluation, residual resistance factor and displacement experiment for the prepared profile agent were carried out. The results show that the profile agent weakly affected the interfacial tension of the ASP flooding. The gelation time could be tuned by adjusting the concentration of the delayed coagulant. The alkali-resistant profile agent with good plugging performance was suitable for deep profile control. When this profile agent was applied in the process of ASP flooding, it could adjust the liquid producing profile and improve the oil displacement efficiency, the recovery ratio was about 4% higher than ASP flooding. The field test of alkali-resistant gel-type profile agent shows that, this alkali-resistant profile agent can achieve good effect, it can enhance oil recovery by 3%.