基于离散裂缝模型致密储层压裂直井动态分析

发布时间：2019-02-19 19:54

【摘要】：针对致密油藏渗流规律表现出的启动压力梯度和应力敏感等非线性特征,基于离散裂缝模型建立致密油藏压裂直井的不稳定渗流模型。由于有限体积方法具有物理意义明确的特点,易于计算压力梯度,方便考虑启动压力梯度的影响,采用该方法对模型进行数值求解,并对压力动态进行敏感性分析。结果表明:启动压力梯度与应力敏感的存在使得压力导数曲线上翘,启动压力梯度与渗透率模数越大,上翘幅度越大,流动阶段越难划分;与启动压力梯度不同,应力敏感使得边界响应段的压力导数曲线上翘;裂缝半长越短,启动压力梯度和压敏效应导致的曲线上翘越明显;裂缝导流能力对早期流动阶段的影响较大,随着裂缝导流能力的增大,压力导数曲线向下移动。
[Abstract]:Based on discrete fracture model, the unstable percolation model of fractured vertical wells in dense reservoirs is established in view of the nonlinear characteristics such as start-up pressure gradient and stress sensitivity in the percolation law of tight reservoirs. Because the finite volume method has the characteristic of definite physical meaning, it is easy to calculate the pressure gradient and consider the influence of the starting pressure gradient. The model is solved numerically and the sensitivity of the pressure dynamic is analyzed by this method. The results show that the existence of starting pressure gradient and stress sensitivity makes the curve of pressure derivative rise, the bigger the starting pressure gradient and permeability modulus, the bigger the upturn amplitude, the more difficult to divide the flow stage. Different from the starting pressure gradient, the stress sensitivity makes the pressure derivative curve of the boundary response section upwarp, and the shorter the crack half length, the more obvious the curve upwardness caused by the starting pressure gradient and the pressure sensitivity effect. The influence of fracture conductivity on the early flow stage is great. With the increase of fracture conductivity, the pressure derivative curve moves downward.
【作者单位】：中国石化胜利油田分公司勘探开发研究院;中国石油大学(华东)石油工程学院;
【基金】：国家自然科学基金青年基金(51504277) 山东省自然科学基金(ZR2014EL016) 中央高校基本科研业务费专项(16CX05018A)资助
【分类号】：TE331

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