Mechanically robust and rapidly degradable hydrogels for temporary water plugging in oilfields

Abstract Hydrogels have been widely used for in‐depth water control and water plugging in most mature oilfields; however, the poor mechanical properties as well as non‐degradable characteristics severely limit their applications. Herein, a multifunctional macromolecular cross‐linker (GA) based on a natural macromolecule, gelatin, is fabricated and used to prepare polyacrylamide hydrogels. Cross‐linking with GA leads to a special network involving physical entanglements that dissipate energy and topological cross‐links that distribute stress. Therefore, the hydrogels manifest remarkable mechanical strength, toughness and tear‐resistance. At the same time, GA can be readily degraded at high temperature, leading to disintegration of the hydrogels. The flow model in porous media reveals that the hydrogels present a significant ability of water plugging and rapid degradation, where the plugging ratio and degradation ratio reach 99% and 100%, respectively. Such mechanical properties and degradation performance enable the hydrogels to serve as a novel temporary water plugging agent for heterogeneous reservoirs of oilfield.