川西地区川主庙剖面泡砂岩中流体运移规律研究

Study on the Fluid Migration of the Bubble Sandstone in the Section of the Main Temple in the West of Sichuan Basin

摘要: 流体的运移方向及规律是研究油气运移方式及路径的重要内容，只有对流体运移方向及规律建立起运移模型，从而更有效指导油气勘探。此次研究区为马林岩向斜北西翼的名山组泡砂岩层，岩性特征为砂岩层与泥岩层交替出现的互层，向斜翼部以砖红色中–厚层砂岩为主，夹薄层泥岩；向斜核部的位置泥岩层以砖红色泥岩为主，夹粉砂岩和细砂岩。由于名山组泡砂岩孔隙流体在向斜内部的运移模式还没有不太清楚，通过对泥岩层裂缝充填物特征研究和元素分析，了解裂缝与流体之间的关系，进行流体运移痕迹研究，得出流体运移期次和运移规律，从而来建立流体在向斜泥岩层中的运移模型。研究表明，该区泥岩层中裂缝整体较发育，流体运移呈现出规律性：向斜翼部地层应力较小，裂缝发育较少，流体做顺层方向运移；向斜中部所受应力较大，裂缝分布呈蜘蛛网状，流体沿着蜘蛛网状通道运移；核部地层应力大且集中，裂缝发育呈十字状，流体沿十字状裂缝通道运移。

Abstract: The direction and law of fluid migration is an important part of oil and gas migration methods and paths, only to establish the migration model, which is more effective in guiding oil and gas exploration. The study area is the bubble sandstone of the Mingshan formation in the north-west Wing of the Ma Linyan syncline, and lithologic characteristic is sandstone and mudstone layer for alternating beds, with red brick’s middle-thick layer sandstone in the syncline wing, interbedded with thin mudstone; and the brick red mudstone in core location of syncline, intercalated with siltstone and fine sandstone. The migration pattern of pore fluid in the Mingshan formation is not clear in internal syncline, through the analysis of the mudstone fracture filling characteristics and elements, we can understand the relationship between the fracture and the fluid, and studied the traces of fluid migration, we can realize the fluid migration times and migration laws, to establish a fluid transport model in the mudstone in syncline. Research shows that the fracture of mudstone layer in this region is the overall development, and fluid migration regularity is that the stress of syncline wing formation is smaller, less cracks, bedding direction of fluid migration; the stress distribution of crack in the middle syncline is big and arachnoid, fluid migration along the arachnoid channel; core formation stress is large and concentrated, cracks show in the cross shaped, and the fluid migration along cross shaped crack channel.