Self‐Healing Hydrogel Blocking Agent Based on Borate Bonding‐Hydrophobic Binding Dual Network

ABSTRACT Borehole wall instability is one of the most serious problems in drilling and completion, and the most common way to solve the problem is to stabilize the borehole wall with sealing materials. This work reports the synthesis, characterization, and evaluation of the double network self‐healing hydrogel containing acrylamide (AM), 2‐acrylamide‐2‐methylpropane sulfonic acid (AMPS), polyvinyl alcohol (PVA) and borax to use as a plugging agent for drilling fluids. The experimental results show that P (AM‐co‐AMPS‐co‐LMA)/PVA DN hydrogel has good temperature and salt resistance. There are a large number of holes in the interior, and the swelling ratio is as high as 217.33%. The mechanical properties test showed that the hydrogel had a high tensile strength of 0.57 MPa and elongation at break of 464.63%. The recovery efficiency of elongation at break is over 87%. Through the pressure plugging test, the steel model with crack widths of 0.5 mm and 1 mm was adopted. 0.8% P(AM‐co‐AMPS‐co‐LMA)/PVA DN hydrogel could withstand the pressure of 5 MPa at 70°C. This kind of hydrogel with good mechanical properties and certain self‐healing properties can be a new material to control leakage.