Investigation of Blocking Characteristics by Particles in Heterogeneous Reservoir

Abstract

A mathematical model of suspension filtration in porous media has been established based on mass conservation principle and characteristics of particles depositing and blocking. On this basis, percolation rules and blocking characteristics of suspension in heterogeneous reservoir were investigated. It is showed that suspension injection could remarkably reduce the permeable ratio and improve the heterogeneity significantly. Low-speed and low-viscosity injection could achieve shallow profile control, and high-speed and high-viscosity injection could achieve deep profile control. Adjusting the injection rate or viscosity of carrying fluid slug at the right time to make the particle retention concentration profile in thief zones and the water-flood front keep consistent could achieve dynamic profile control. For the reservoirs without a good interlayer, the optimum injection rate and viscosity of carrying fluid were chosen based on the connectivity of layers, and in the reservoirs with good interlayers the injection rate and viscosity should be lowered appropriately under the field permitting conditions. When the suspension concentration was constant, the instantaneous fractional flow of high permeable layer first decreased sharply and then ramped up with the increasing injection volume. Initial percolation coefficient is the basis of a high utilization of suspension and a good result in profile control. Key words: Heterogeneous reservoir; Suspension; Percolation; Profile control; Retention concentration; Blocking characteristics