A New Self‐Healing Green Polymer Gel with Dynamic Networks for Flow Control in Harsh Reservoirs

Abstract

Hydrogels are widely used in flow control of underground reservoirs, a self‐healing in situ cross‐linked polymer gel system with a dynamic covalent adaptive network and dynamic disulfide bond is designed and constructed with cystine hydrochloride containing disulfide bond as a green cross‐linking agent. The polyacrylamide/cystine system can form a gel at temperatures above 110 °C, the dynamic disulfide bonds in the gel network make the hydrogels have excellent toughness and self‐healing properties and the maximum toughness value of the self‐healing gel is 57.5 MJ m−3, and the self‐healing efficiency can reach 88%. At the same time, the storage modulus of the gel can reach more than 2000 Pa with the addition of nano SiO2. The cross‐linked gel formulated using formation water is stable at 170 °C for more than 270 days. The modulated flooding experiment results show that the new gel system can effectively reduce the water content and increase the recovery rate by 32.2%. At the same time, the formation damage test shows that the average plugging rate of the gel is 95%, and the permeability damage is less than 15%. This new self‐healing green gel system can replace existing toxic gel systems and prioritize fluid flow control in harsh reservoir conditions.