Experiment and numerical simulation on transportation laws of proppant in major fracture during slick water fracturing

When slick water fracturing is carried out, a fracture network with the major fracture as the trunk is formed in the reservoir by pumping fracturing fuid at high fow rate, so the laying situations of proppant in the major fracture has direct effect on the productivity of oil and gas wells. In this paper, the independently designed large visual plate fracturing device was used to investigate the transportation laws of proppant in the major fracture in the process of high rate pumping. The corresponding numerical model was established to simulate the laying form of sand bank in different time. And the infuential laws of turbulence on the laying form of proppant were analyzed. It provides the theoretical guide for the effective laying of proppant in the major fracturing in the process of slick water fracturing. It is indicated that the laying law of proppant in the major fracture during the slick water fracturing is different from that during low fow rate fracturing. The proppant frstly generates a lower sand bank at the entrance of the major fracture and a higher sand bank farther from the entrance, and then covers both sand banks periodically layer after layer until the balance height is ultimatelyreached. In the case of high fow rate fracturing, turbulence occurs easily and take the proppant which is temporarily settled at the entrance of the major fracture into the deep part of the fracture again. And consequently the settlement structure of approximate cirrus shape is formed. The numerically simulated laying form of proppant is consistent with the result of physical experiment. It is proved that the numerical model established is practical.