Prediction on the reservoir dilatation results by squeeze preprocessing in SAGD wells

The super heavy oil reservoirs in Fengcheng Oilfield, Xinjiang are characterized by high viscosity and strong heterogeneity, so the preheating period of SAGD development is generally long. The squeeze dilatation of reservoirs before the steam injection for preheating can shorten the preheating period effectively and reduce economical and environmental cost. In order to optimize the squeeze design plan, it is firstly necessary to predict the squeeze dilatation effect of reservoirs. In this paper, the Drucker-Prager constitutive model was used to conduct fluid-solid coupling finite element analysis on the squeeze process of one SAGD well in Zhong 1 Block, Fengcheng Oilfield on the basis of the previous rock mechanical experiment results. And accordingly pore pressure, porosity, vertical strain, Mises stress and distribution of equivalent plastic strain after the squeeze were obtained. It is indicated that the pressure difference leads to the vertical seepage of injected fluid into the deep zones of reservoirs, the vertical uplifting of reservoirs, and the distribution of pore pressure and porosity in the shape of semi-ellipse with the injection/production well as the long axis. The tensile dilatation of pore elasticity is dominant in the reservoirs, so the strain shear dilatation of plastomer only occurs quite close to the screen pipe. The research results can not only provide the theoretical guidance for the optimization of squeeze plan, but also the geological mechanical parameters for the numerical reservoir simulation in the stages of preheating and production.