大量研究表明,低渗透变形介质油藏存在压敏效应和启动压力梯度.针对低渗透油藏特征,基于Terzaghi有效应力和岩石本体有效应力的应力敏感指数,根据稳定流理论,引入动态启动压力梯度,推导建立了低渗透变形介质油藏的油井径向压力预测方程；并通过实例分析研究各参数对动态启动压力梯度影响.研究结果表明:基于Terzaghi有效应力计算渗透率和动态启动压力梯度的减小或增加幅度较大；而基于岩石本体有效应力计算的减小或增加幅度较小.基于Terzaghi有效应力动态启动压力梯度,渗透率越小,变形系数越大,有效应力变化对其影响越显著；而有效应力对基于岩石本体有效应力动态启动压力梯度的影响不大.针对两种有效应力计算的动态启动压力梯度影响差异大,需进一步的研究.%A lot of results indicate that there is the pressure sensitive effect and start-up pressure gradient in the low permeability deformation reservoirs. In view of the characteristic, based on the Terzaghi s effective stress and the primary effective stress, based on the steady seepage theory, creating a dynamic start-up pressure gradient, the radial pressure distribution prediction model was established for the low permeability deformation reservoir. The result shows indicate that the decreasing or increasing extent of the penetration and dynamic start-up pressure gradient based on the Terzaghi's effective stress is much bigger then the penetration and dynamic start-up pressure gradient based on the primary effective stress. The smaller the permeability, the bigger the distortion coefficient, the effect stress changes have a significant effect on the dynamic start-up pressure based on the Terzaghi's effective stress, but the effect stress changes have a little effect on the dynamic start-up pressure based on the primary effective stress.
展开▼
