Abstract:For reservoirs with high shale content and low permeability, many reports have pointed out that shrinkage swelling agents can reduce pressure and increase injection, but there is no research report on the relevant mechanism. In this paper, the effect of DSJ-1 shrinkage swelling agent addition on anti swelling ratio and shrinkage swelling ratio was investigated, and the bentonite before and after treatment were characterized by XRD, XRF, zeta potential, thermogravimetry, particle size distribution and optical microscope. Through characterization, the anti swelling and shrinkage swelling mechanisms were analyzed. It was found that DSJ-1 was mainly adsorbed on the clay surface during the anti swelling treatment, and the adsorption amount and zeta potential had the greatest impact on the anti swelling rate. During the shrinkage swelling treatment, DSJ-1 was mainly adsorbed between crystal layers, and the particle aggregate size and zeta potential affected the shrinkage swelling rate.