火山岩压敏性的定量综合评价及其对气井产能影响

以往对于火山岩压敏性评价多限于定性分析且影响因素分析较片面，基于6块火山岩岩样的压力敏感性实验结果，结合岩石应力变形理论，建立了一种相对完善的定量化综合评价方法。分析了影响火山岩岩石压敏性的因素，其主控因素为裂缝发育情况和岩石孔隙结构。同时对影响岩石压敏性的影响因素进行了定量综合评价，其评价结果与实验结果的高度吻合(直线拟合R²为0.94)，验证了该评价方法的可靠性。火山岩压敏性的各影响因素的影响因子由大到小依次为裂缝类型、裂缝充填情况、岩石渗透率、岩石孔渗比、裂缝条数、裂缝宽度、岩石孔隙度、黏土矿物含量和井深。此外，还建立了压敏条件下火山岩气井的产能方程，给出一种预测不同地层压力下火山岩气井产能的方法，分析了压敏性对火山岩气井产能的影响，其结果表明：岩石压敏性越强，地层压力下降越多，压敏性带来的附加产能损失越大。

Quantitative Comprehensive Evaluation on Stress-sensibility of Volcanic Rocks and Its Influence on Gas Well Productivity

Previous evaluations on stress-sensitivity of volcanic rocks are limited to qualitative analysis, and the influence factors of the stress-sensitivity are not comprehensive. Basing on the results of stress-sensitivity experiment on volcanic rocks and the theory of stress-deformation, this paper has established a relatively comprehensive quantitative evaluation method. This paper has analyzed the factors that affect the stress-sensitivity of volcanic rocks, finding that fracture development situation and pore structure are the key factors. The result of stress-sensitivity experiments is highly consistent with the result of quantitative comprehensive evaluation on stress sensitivity of volcanic rocks with the 0.94 of linear fitting R², verifying the high reliability of this evaluation method. All the influence factors of stress-sensitivity are fracture type, fracture filling situation, permeability, the ratio of porosity to permeability, fracture number, fracture width, porosity, clay mineral content and depth in descending order. In addition, the volcanic gas well productivity equation with stress-sensitivity is established, which can forecast gas well productivity with stress sensitivity under different reservoir pressure. And the analysis result of the effect of stress-sensitivity on gas well productivity shows that the stronger the stress sensitivity is, the more the gas well productivity losses under the same condition.