Synthesis and Properties of High Elastic Dual Network Polymer Particle for Profile Control and Water Shutoff

In view of the problems of high water content, high temperature and high salinity of formation water in old oilfields, the elasticity and strength of conventional swelling particle profile control agent rapidly decline after swelling, and the ability of heat resistance and salt tolerance is insufficient, so it is difficult to meet the demand for high-strength plugging near wellbore areas. Therefore, a high elastic dual network polymer particle profile control and water shutoff agent was prepared by two-step polymerization. Firstly, 2-acrylamide-2-methylpropane-sulfonic acid (AMPS) was used as monomer and N, N’- methylene bisacrylamide (MBAA) was used as crosslinker to form the first cross-linked network product which is rigidity by photoinitiated polymerization; Then, the first cross-linked network product was immersed in a polymerization system composed of acrylamide (AM), crosslinker (MBAA) and initiator, and the polymerization system slowly diffused into the first gel network to make it fully swelling, and the second cross-linked network product which is flexibility was formed by photoinitiated polymerization; Finally, the high elastic dual network polymer particle profile control and water shutoff agent was prepared by freezing, drying, grinding and screening. The experimental results showed that when the molar ratio of AMPS to AM was 1:40, the initial temperature was more than 20 ℃, the dual network polymer with high elasticity, high strength, heat resistance and salt tolerance could be prepared. The elastic modulus of the polymer is more than 2000 Pa, and the tensile deformation can reach 345%, Under the condition of 90 ℃ with the salinity is 20 × 104mg/L, it can be stable for 120 days, the core plugging rate is greater than 94.4%, which meets the technical requirements of high-strength plugging near the well in high-temperature and high salinity reservoirs.