Study on the time-variant rule of reservoir parameters in sandstone reservoirs development

Abstract

ABSTRACTAim at solving the problem on the time-variant of reservoir parameters such as permeability and porosity during the water flooding process of sandstone reservoirs and the lack of microscopic mechanism studies, which has an important impact on reservoir development. In this paper, based on the a network model typical unconsolidated sandstone reservoirs and a comprehensive consideration of the microscopic mechanisms of loss, trapping, and migration of micro-particles in the pore throat, a three-dimensional network simulation method of layer parameter variation was used to simulate and study the change law of physical parameters such as porosity and permeability under different conditions. Simulation results showed that: In the process of long-term water flooding, particles in the pore throat will fall off, and some particles will flow out of the reservoir with the injected fluid, resulting in a distribution of pore throat radius. There was a small change in the circumference, and the pore throat radius showed an overall increasing trend, and the reservoir connectivity was enhanced. The permeability and porosity gradually increased, and the increased amplitude gradually decreased. The strength of water injection and the degree of clay cementation affect the extent of changes in reservoir permeability and porosity by affecting the exfoliation rate of the particles. The study further reveals the time-varying microscopic mechanism of sandstone reservoir parameters, and provides a theoretical basis for the numerical simulation of time-varying reservoir parameters.