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 SiO 2 . 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.