Abstract:In order to solve the problems of large frictional resistance at the front end and low viscosity at the tail end of volumetric fracturing in shale reservoirs. The steric hindrance of twin tail monomers with different carbon chain lengths, mean square terminal distance and mean square displacement (MSD) of the polymer materials were studied based on molecular dynamics. The drag reducer LMA-AM-DiC12AM (LAD) was synthesized by micellar polymerization with Lauryl methlacrylate (LMA), Acrylamide (AM) and N,N-dodecyl acrylmaide (DiC12AM). The rheological properties, drag reduction and sand carrying properties of LAD solution were studied by rheometer and friction tester. The results show that DiC12AM monomer has small steric hindrance, the best chain flexibility of polymer materials molecules, the best ability to bind water molecules, and the great drag reduction potential. LAD has good shear stability (viscosity is 75mPa·s) and shear recovery performance. It can withstand a temperature of 60℃ at present. Its drag reduction rate reach 67.4%. The average sedimentation rate of 40/70 mesh ceramsite is 2.05×10-4 mm/s. The polymer materials agent has both drag reduction and sand carrying properties, which is basically consistent with the simulation results.