页岩储层非稳态渗透率测试方法综述

为了研究页岩储层非稳态渗透率测试方法,对国内外脉冲衰减法和压汞法相关文献进行了广泛深入地调研。详细阐述了岩芯柱脉冲衰减法、岩屑脉冲衰减法、脱气法三种脉冲衰减渗透率测试方法的实验原理、数学处理方法、影响因素、适用条件和存在的问题。针对压汞法,给出了基于不同理论的预测模型。研究结果表明：岩芯柱脉冲衰减法具备较高的测试效率和精度,能够测试不同围压条件下的储层渗透率,为页岩储层原始条件下的渗透率测试和应力敏感性研究提供了有效手段;岩芯柱脉冲衰减法对实验仪器和样品制备要求严格,适用于室内对页岩等致密储层进行精密的渗透率测试,且数学处理上还需要进一步的研究,以区分基质和天然裂缝的作用。岩屑脉冲衰减法不受样品形状限制,缩小了样品测试尺寸,理论上能够避免天然裂缝的影响,为页岩储层基质渗透率测试提供有效手段。脱气法和压汞法精度相对较低,测试结果可作为参考数据。

The Review of Non-Steady Permeability Test in Shale Gas Reservoir

The domestic and international references related to the pulse-decay and mercury injection permeability measurement of tight reservoir were extensively reviewed to study the non-steady permeability measurement methods of shale gas reservoir. The experimental principles, mathematical treatments, influencing factors, applications and limitations of the core-plug pulse-decay, cutting pulse-decay and degassibility method were detailed presented. The permeability prediction models of the mercury injection based on different theories are also provided. The study shows that the core-plug pulse-decay measurement with high efficiency and precision is capable of measuring the permeability under different confining pressures, which will be beneficial to the study of shale gas reservoir stress sensibility. The core-plug pulse-decay experiment which has a strict requirement for the experimental apparatus and core plug preparation is applicable to the high precision permeability measurement. The mathematical treatment of the core-plug pulse-decay needs to be further studied to distinguish the properties of matrix and natural fracture. The cutting pulse-decay experiment has no limitation to the sample shape and reduces the sample size, which could theoretically avoid the impact of natural fracture in shale gas reservoir and measure the matrix permeability of shale gas reservoir more accurately. Due to the relatively low experimental precision, the permeability measurements of the degassibility and mercury injection methods are available as reference.