Stress Sensitivity of Tight Sand Reservoir and Its Influence on Productivity of Well

In order to study the stress sensitivity of tight sand reservoir and evaluate their impact on the productivity, physical and mathematical simulation is carried out under the scanning electron microscopy (SEM), the casting thin sections and the stress sensitivity test technology. The results show that porosity and permeability decreases with pressure, the damage mode of porosity and the permeability can be described as "Falling quickly then falling slowly." The relative loss rate of porosity is from 4.88% to 8.46%, meanwhile, permeability has stronger stress sensitivity and the relative loss rate of permeability is from 63.86% to 86.14%. The porosity stress sensitivity is connected with the microscopic pore structure, pore size and rock particles compressive capacity, and permeability is mainly affected by the pore distribution and pore size distribution. A productivity equation of tight reservoir in which the stress sensitivity of the porosity and permeability is considered shows that as the reservoir properties become worse, the stronger the rock sensitivity, the higher the degree of impact on the production. This study provides reference for reducing sensitivity damage in tight sandstone reservoirs and improving gas recovery.