Numerical Study of Percolation Mechanism in Heavy-Oil, Unconsolidated Sandstone Reservoirs with Frac-Pack Wells

Abstract

Due to the faultiness of simulation in heavy-oil, unconsolidated sandstone reservoirs with frac-pack wells, a mathematical model was established considering reservoir stress sensitivity, start-up pressure gradient, and fracture flow conductivity failure. Based on the field data of one block in Bohai Bay, together with the numerical model, the percolation mechanism was studied. Results show that for heavy-oil, unconsolidated sandstone reservoirs with frac-pack wells, the sweep efficiency is enlarged and the reservoir pressure gradient is lowered, which result in better productivity and sand prevention results. The flow pattern is proved to be an intermediate of radial flow and bi-linear flow, which is characterized with the concept of fracture flow ratio. The lower the reservoir permeability, the higher the fracture flow ratio and more likely bi-linear flow pattern occurs, thus the advantage of the frac-pack fracture will become more apparent.