焦石坝地区构造演化及其对页岩气成藏的控制

发布时间：2018-04-13 18:52

本文选题：焦石坝 + 构造特征　；参考：《中国矿业大学》2017年硕士论文

【摘要】：焦石坝页岩气田是我国首个实现商业化开发的页岩气田,系统研究焦石坝地区的构造发育特征、演化规律、页岩气地质特征、构造演化对页岩气成藏的控制作用及构造保存模式,对国内海相页岩气进一步勘探开发具有重要参考价值。本论文在充分研究区域地质构造背景基础上,运用传统地质调查方法,配合室内构造地质学、模拟软件运用等技术,对焦石坝构造几何学特征、运动学特征及其演化过程展开了全面研究,并综合研究了地质构造演化对页岩气成藏过程的控制。主要获得了如下认识:焦石坝背斜主要受控于NE向、NW向及近SN向三组逆断层,东部和南部地层受断裂改造作用明显;地表节理走向主要以NWW、NE和SN三个方向为主;显微构造和岩石组构反映了NW-SE和NE-SW~NNE-SSW向多方向挤压过程,构造活动时间在120Ma之后,85Ma-65Ma(燕山晚期)为强烈改造期,地层总缩短量为3.8km,缩短率为16.7%;受大巴山造山带和江南-雪峰山造山带联合控制,焦石坝中生代以来构造演化史可分为五期:加里东运期,五峰组-龙马溪组富有机质泥页岩的沉积,到志留纪末,地层发生隆起并剥蚀,区内未发生褶皱作用;海西-印支早期,地层的持续沉降,到印支期海相向陆相沉积的交互,焦石坝构造变形微弱;印支晚期-燕山早期,NNW-SSE向挤压,形成一系列NE向断层雏形;燕山晚期-喜马拉雅早期,NNW-SSE~NWW-SEE向挤压,焦石坝NE向边界断层形成的主要时期;喜马拉雅晚期,NE-SW向挤压,乌江断裂系主要形成于该时期。焦石坝五峰组-龙马溪组泥页岩厚度主要介于70~100m,埋深范围为2250~5000m,整体呈现东部埋深浅西部埋深大的规律,中部埋深相对较浅,埋藏深度主要分布在2250~3000m,泥页岩有机质热演化程度较高,已达过成熟阶段;区内五峰组-龙马溪组泥页岩经历了加里东晚期、海西晚期、印支早期及燕山晚期-喜马拉雅期的四次抬升作用。有机质成熟生烃经历了未成熟到过成熟的整个阶段,完成了从少量生烃到干气生成的全过程。燕山晚期之后的快速抬升终止了页岩有机质生烃过程,并对页岩气藏进行了重新调整或破坏;焦石坝页岩气藏具有构造改造时间晚、构造改造强度弱、封闭断层发育以及地层产状平缓且埋深适中等有利保存条件;总含气量分布在5.8~6.7m3/t的范围,在当前焦石坝主体埋深2250~5000m范围内,页岩气以游离气为主,约占总含气量的70%。
[Abstract]:Jiaoshiba shale gas field is the first shale gas field to be commercially developed in China. The structural development characteristics, evolution rules and shale gas geological characteristics of Jiaoshiba area are systematically studied.The tectonic evolution controlling the formation of shale gas and its structural preservation model have important reference value for further exploration and development of marine shale gas in China.In this paper, based on the study of the regional geological structure background, the structural geometry characteristics of Jieshiba are studied by using the traditional geological survey method and the techniques of indoor structural geology and simulation software.The kinematic characteristics and evolution process are studied comprehensively, and the control of geological structure evolution on shale gas accumulation process is studied synthetically.The main results are as follows: the anticline of Jiaoshiba is mainly controlled by three groups of reverse faults in NE direction, NW direction and near SN direction, the eastern and southern strata are obviously reformed by fault, and the surface joint strike is mainly in the three directions of NWW-NE and SN;The microstructures and rock fabric reflect the multi-direction compression process of NW-SE and NE-SW~NNE-SSW, and the tectonic activity time is 85 Ma-65 Ma (late Yanshanian) after 120Ma.Under the control of the Daba orogenic belt and the Jiangnan-Xuefengshan orogenic belt, the tectonic evolution history of Jiaoshiba since Mesozoic can be divided into five periods: Caledonian transport period.By the end of Silurian, there was uplift and denudation, no fold in the area, and the continuous subsidence of the strata in the early Hercynian-Indosinian period, and the interaction between the marine facies and the continental facies during the Indosinian period.The tectonic deformation of Jieshiba is weak, the NNW-SSE compression of late Indosinian to early Yanshanian formed a series of NE trending faults, the NNW-SSEN NWW-SEE compression from late Yanshanian to early Himalayan, the main stage of NE boundary fault formation of pyroshiba.In the late Himalayas, the Ne-SW compression occurred, and the Wujiang fault system was mainly formed in this period.The shale thickness of Jiaoshiba Wufeng formation and Longmaxi formation is mainly between 70m and 100m, and the buried depth ranges from 2250m to 5000m. The whole presents the law of large buried depth in the east, shallow in the west, and relatively shallow in the middle.The buried depth is mainly distributed at 2250 ~ 3000m, the thermal evolution of organic matter in shale is relatively high, and it has reached the mature stage, the mud shale of Wufeng formation and Longmaxi formation has experienced the late Caledonian and late Hercynian stages in the area.Four uplifts in the early Indosinian and late Yanshanian-Himalayan periods.The mature hydrocarbon generation of organic matter has gone through the whole stage of immature to over-mature, and the whole process from a small amount of hydrocarbon generation to dry gas generation has been completed.The rapid uplift after the late Yanshanian period terminated the hydrocarbon generation process of shale organic matter and readjusted or destroyed the shale gas reservoir.The development of closed fault and the favorable preservation conditions such as flat formation and moderate buried depth, the total gas content is distributed in the range of 5.8~6.7m3/t, and the shale gas is mainly free gas in the range of 2250m ~ 5000m of the main buried depth of the main body of the coke stone dam, accounting for about 70 ~ (th) of the total gas content.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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