低渗火山岩气藏可动流体百分数及其影响因素

针对火山岩储层成岩机制与常规沉积储层差异大、岩性种类繁多、储层孔隙结构复杂等特点，综合使用离心
实验、核磁共振、恒速压汞及CT 成像等实验技术，对大庆徐深、吉林长岭和新疆滴西3 个火山岩气田可动流体百分数
及其影响因素进行了对比研究。实验结果表明，气水离心标定低渗致密火山岩气藏可动流体百分数使用的离心力应
为2.76 MPa，不同渗透率级别火山岩储层可动流体微观分布规律具有明显差异，渗透率越大，较大喉道控制的可动流
体比例越大，气藏开发难度越小，渗透率越小，较大喉道控制可动流体比例越小，0.100 mD 是可动流体微观分布规律
发生明显变化的临界渗透率。108 块岩芯可动流体百分数平均值为23.62%，长岭气田可动流体百分数最大，滴西气田
可动流体百分数最小。CT 成像与恒速压汞实验结果表明，孔喉大小及其匹配关系和裂缝发育程度是影响火山岩储层
可动流体百分数大小的主要因素。

Study on the Movable Fluid Saturation and its Influencing Factors ofLow Permeability Volcanic Gas Reservoir

In view of the factors that the diagenetic mechanism of volcanic reservoir is different from the conventional depositional
sandstone reservoir，the micro-pore structure of the volcanic is more complex than that of sandstone reservoir. The movable
fluid saturation of Xushen，Changling and Dixi volcanic gas reservoirs were systematically studied by using the centrifugal
experiment，NMR，constant-rate mercury injection and CT technology. The experimental results indicate that the suitable centrifugal
force used to obtaining the irreducible water saturation in centrifugal experiment is 2.76 MPa. The micro-distribution
feature of the movable fluid corresponding to different permeability reservoir is different. The larger the permeability，the
greater the proportion of the movable fluid controlled by the larger throat. 0.100 mD is one of the critical permeability values
when the reservoir permeability larger or less than it，the micro-distribution feature of the movable fluid is different. The average
of the movable fluid saturation of the three gas reservoir is 23.62%. The CT image and constant-rate mercury injection
experimental results suggested that the reservoir fracture and pore-to-throat ratio are the main factors affecting the movable
fluid saturation.