鄂西利川一带中生代及现今构造应力场研究

发布时间：2018-03-13 04:39

本文选题：弹-塑性增量法　切入点：构造应力场　出处：《中国地质大学(北京)》2017年博士论文　论文类型：学位论文

【摘要】：鄂西利川地区东属湘鄂西隔槽式褶皱带,西属川东隔档式褶皱带,位于二者的过渡区域。湘鄂西-川东地区以发育隔槽-隔档式褶皱带为整体特征,其主体形成时期为中生代。在川东隔档式褶皱带东南缘焦石坝地区发育的焦石坝五峰-龙马溪组泥页岩是页岩气田的重要储层,亦是典型的裂缝型油气藏。长期以来,有关该页岩气田的大量裂缝预测工作都集中在地震和测井解释上,而忽略了构造应力场对于裂缝发育起到的控制作用。鄂西利川一带形成隔槽-隔档式褶皱带的晚侏罗世构造应力场是焦石坝地区褶皱和断层形成的基础,而焦石坝现今构造应力场的研究可以预测裂缝发育有利区。本文通过野外观测鄂西利川一带发育的共轭剪节理产状和地层接触关系,识别出该地区在晚侏罗世发生的一次挤压构造事件,缩短方向为北西-南东向。根据超显微构造的石英晶格位错密度法得到该次构造事件的作用力大小为44.1MPa～62.6MPa。另外,根据本研究掌握的地震、测井、水力压裂等资料,获得焦石坝地区现今构造应力场挤压方向约为SE120°,JY1井海拔-1800m～-4800m现今构造应力场大小约为12MPa～33MPa。利用弹-塑性增量构造应力场数值模拟法,得到了鄂西利川一带焦石坝地区现今构造应力场数值模拟差应力等值线图,总结了差应力分布规律与特征。平面上,焦石坝地区-1800m～-4800m每隔600m一层的裂缝发育有利区带主要集中在东北部和西南部,裂缝展布方向与断层走向相近,为NE走向。垂向上,焦石坝地区在海拔-2400m～-3600m裂缝发育有利区面积较大,随着深度的增加,中心部位的裂缝逐渐变的不发育。上述各层的应力场方向图总体上的分布规律和特征较为相似,每个单元略有不同,变化范围在SEE118°～SEE130°左右。此外,因为人工裂缝受最大主应力及先存破裂的影响较大,所以页岩气的水平井部署及开发需要考虑局部最大主应力方向,因此本研究所获得的焦石坝地区现今应力场模拟方向图可为该区页岩气开发水平井部署提供参考和指导。
[Abstract]:The east part of Lichuan area in western Hubei Province belongs to the channel type fold belt in the west of Hunan and the west part of the basin, and the west part of the area is located in the transitional region of the two regions. The shale of Jiaoshiba Wufeng Longmaxi formation is an important reservoir of shale gas field and is a typical fractured reservoir for a long time. A great deal of work on the prediction of fractures in the shale gas field is focused on seismic and logging interpretation. The tectonic stress field of late Jurassic is the basis of fold and fault formation in Jiaoshiba area. The present tectonic stress field of Jieshi Dam can predict the favorable area of fracture development. In this paper, the conjugate shear joint occurrence and stratigraphic contact relationship developed in the area of Lichuan, western Hubei Province, are observed in the field. A compressional tectonic event occurred in the late Jurassic in this area was identified, and the shortening direction was NW-SE. According to the quartz lattice dislocation density method of ultramicro structure, the force of the tectonic event was obtained to be 44.1 MPA (62.6 MPA). According to the data of earthquake, logging, hydraulic fracturing and so on, It is obtained that the compression direction of the present tectonic stress field in Jiaoshiba area is about SE120 掳-1800m ~ 4800m above sea level. The present tectonic stress field of Jiaoshiba area is about 12MPa1 33MPa. The numerical simulation method of elastic-plastic incremental tectonic stress field is used. In this paper, the numerical simulation of differential stress isoline map of present tectonic stress field in Jiaoshiba area, western Hubei Province is obtained, and the law and characteristics of differential stress distribution are summarized. In Jiaoshiba area, the favorable zones of fracture development in -1800m / 4800m / 600m layer are mainly concentrated in the northeast and southwest, and the distribution direction of the fractures is similar to the fault strike, which is NE strike. Vertical upward, the favorable area of fracture development in Jioshiba area is larger at the altitude of -2400m- 3600m. With the increase of depth, the cracks in the center gradually become undeveloped. The distribution and characteristics of the stress field pattern in the above layers are similar in general, each unit is slightly different, and the range of variation is about SEE118 掳SEE130 掳. Because artificial fractures are greatly affected by maximum principal stress and pre-existing fracture, the direction of local maximum principal stress should be taken into account in the deployment and development of horizontal well of shale gas. Therefore, the simulated pattern of present stress field in Jiaoshiba area can provide reference and guidance for the deployment of horizontal well in shale gas development in this area.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P618.13

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