关键词: 固结模型, 渗流变化, 压力梯度, 数值分析, 近井带

Abstract: The physical properties in actual developed reservoirs change under the stimulation of low-frequency vibration. However, no change in porosity and pressure is usually assumed in classic consolidation model. The analysis of solid deformation is often based on a one-dimensional physical model with constant pressure (or pressure gradient) condition. Therefore, it is usually inadequate to simulate the effect of seismic production technology near the wellbore in actual developing reservoirs, which are with varying flow velocities and pressure gradients, with the classic mathematic model and one-dimensional physical model. The control equations of consolidation model for low permeability porous media are re-derived from the continuity equations of fluid and solid. Considering different assumptions of variation extents of porosity and pressure, three consolidation models are given. Numerical simulation is then carried out with one-dimensional (with constant pressure gradient) or radial (with changing pressure gradient) physical model. The effect of seismic production technology as well as its sensitivity under different fluid and vibration parameters are evaluated with different consolidation models. Because of the influences of the inertia effect of initial flow and the strong stress sensitivity in low permeability reservoir, the increases of pressure, flow velocity, and porosity are found to be lower under vibration than the case without vibration in one-dimensional model. However, the wave-induced effect behaves differently in radial physical model. The increases of pressure and porosity are both higher under vibration than the case without vibration, and the increase of flow velocity becomes lower under vibration. As the vibration parameter increases, the volatility of values representing the wave-induced effect becomes stronger when simulated with radial physical model and different consolidation models. The results reflect that it is necessary to carry out a dynamic analysis on the complex effects of artificial seismic technology in actual developing reservoirs.

Key words: consolidation model, seepage change, pressure gradient, numerical analysis, nearby wellbore