广安地区须家河组低阻气层形成机理

川中广安地区上三叠统须家河组低电阻率气层的形成受多方面因素的影响。分别对各个影响因素进行分析后认为，其中最主要的因素为：高束缚水饱和度、高地层水矿化度；再者，该地区普遍发育的菱铁矿、黄铁矿也对此有很大的影响；而粒度、黏土含量等因素则影响较小。最终将该地区须家河组低电阻率气层的类型定义为具高矿化度-高束缚水饱和度且含特殊导电矿物的低电阻率气层。

Formation Mechanism of Low-resistivity Gas Reservoirs in Xujiahe Formation of Guang'an Area

The Xujiahe formation low-resistivity gas payzones were formed by many factors in the Upper Triassic of Guang'an area, Central Sichuan Basin. This paper reckons after study that high SWB (saturation of water irreducible) and high WS (formation water salinity) are two main reasons leading to low-resistivity gas pay, on which the well-developed siderite and pyrite in this area have great impact, whereas the size of granularity and the content of clay have little effect. Therefore the Xujiahe formation gas pay in this area should be a kind of low-resistivity gas-bearing reservoirs with high degree of mineralization and high SWB, containing special conductive minerals.