Feasibility Study on the Microspheres for Deep Profile Control Technology in High Permeability of High Temperature and High Salinity Reservoirs

In order to obtain polymer microsphere for profile control and water shutoff with good suspension, high temperature resistance and high salinity tolerance, micrometer DCA (divinylbenzene-co-acrylamide) microsphere which had a three-layer structure was synthesized by the monomer of acrylamide, initiator of azobisisobutyronitrile, crosslinking agent of divinylbenzene and emulsifier of ethoxylated lauryl alcohol sulfate. Basic performance of DCA microsphere was evaluated, including temperature resistance, plugging capacity, effect of profile control and water shutoff and method optimization. The results showed that the particle size of DCA microsphere ranged from 2 μm to 339 μm and the shell had a Nano porous structure. The temperature resistance of DCA microsphere was up to 300°C. The residual resistance coefficient of each segment along artificial homogeneous cylindrical core was still more than 2 with a strong deep plugging efficiency. After water flooding of oil in two-dimensional heterogeneous cores was carried out, the slug of DCA microspheres was injected. The amplitude of enhanced oil recovery was up to 10.18% in stage of the subsequent water flooding. On the basis of the subsequent water flooding, the recovery of carbon dioxide flooding was 19.64%. Feasibility methods which were the plugging of DCA microspheres and carbon dioxide flooding on deep profile control technology in high permeability of high temperature and high salinity reservoirs have been roposed.