Study on Gel Plugging Agent and Plugging Mechanism Based on Hydrophobic Association

lost circulation has long been a major challenge affecting the safety and efficiency of drilling operations.​ In this study, a gel plugging agent (LAS) was synthesized via free radical polymerization using ​lauryl methacrylate (LMA)​ as the hydrophobic monomer and ​acrylamide (AM), ​2-acrylamido-2-methylpropanesulfonic acid (AMPS), and ​acrylic acid (AA) as hydrophilic monomers. The mechanical properties of the gel were enhanced by the coordination interaction between Al³⁺ metal ions and carboxyl groups on the polymer molecular chains. The results demonstrated that the LAS gel exhibited ​re-crosslinkable characteristics, along with excellent ​plugging performance​ and ​self-adaptive properties​ under high-temperature and high-pressure conditions. Under conditions of ​120℃ and 6 MPa pressure, the leakage volumes of 2% LAS gel for simulated fracture sand beds with particle sizes of ​20-40 mesh, ​40-60 mesh, and ​60-80 mesh​ were ​69.5 mL, ​58.3 mL, and ​41 mL, respectively. This plugging performance significantly surpassed that of conventional gels and traditional plugging agents. Additionally, the LAS gel demonstrated superior ​swelling and rheological properties​ across varying temperatures and salinity levels. It could form a stable plugging layer under formation temperature activation, effectively reducing leakage volume. The ​dynamic re-crosslinking capability​ of the LAS gel ensured robust plugging effects even in extreme high-temperature and high-pressure environments, highlighting its potential for application in ​workflow leakage control.