【作者】 鲁霞；

【导师】 王绪本；

【作者基本信息】 成都理工大学 ， 信号与信息处理， 2011， 硕士

【摘要】 论文以龙门山地质地球物理结构为背景,以大地电磁测深法为手段,通过对穿越龙门山构造带及川西前陆盆地的大地电磁测深剖面的电性结构研究,结合地震及地质构造资料,探讨龙门山逆冲推覆构造深部电性结构,主滑脱面几何形态,川西前陆盆地可能存在的古隆起与古凹陷,川西坳陷基底构造等,为油气背景研究提供地质地球物理依据。论文收集松潘—利川—邵阳地质地球物理大剖面中安县—遂宁段大地电磁资料进行重新处理解释。重点对数据进行曲线类型分析,了解区域基本电性层;对视电阻率、相位断面图进行分析,认识区域整体电性结构,构造轮廓和断裂分布情况等;对极化特征进行分析,了解区域构造走向和二维性;对总纵向电导进行分析,了解基底起伏状况;利用一维Bostik变换,确定反演深度,为二维反演提供初始模型。采用一维Bostik反演的结果作为初始模型,并用其他资料辅助约束,进行二维Occam反演,所用反演模式有TE、TM和TE+TM联合反演,最终选择联合反演结果进行解释。根据大地电磁二维Occam反演结果与反射系数成像结果,研究安县—遂宁段上地壳电性结构。利用电性结构特征,结合地表地质构造观测,将安县—遂宁大地电磁剖面划分为三个电性结构差异明显的电性结构带:龙门山构造带东缘电性结构带,川西前陆凹陷电性结构带,川中电性结构带,详细研究了三个电性结构带的特征。根据电性结构特征首次推测古隆起与古凹陷的存在。论文根据碌曲—龙门山—中江大地电磁剖面、马尔康—都江堰—郫县大地电磁剖面、安县—遂宁大地电磁剖面测深和WFSD-1音频大地电磁剖面,分析龙门山构造带逆冲推覆构造主滑脱面映秀断裂的几何形态与逆冲推覆构造深部电性结构。利用碌曲—龙门山—中江大地电磁剖面,安县—遂宁大地电磁剖面与映秀—简阳超长周期大地电磁剖面,首次编制了川西前陆盆地中段基底埋深图,用于探讨基底构造与埋藏深度,由于基底构造控制沉积盖层的地质演化,进而控制川西海相地层的沉积,在基底构造中寻找局部隆起构造,有利于进一步寻找对油气聚集有利的环境。根据大地电磁剖面古隆起与基底研究油气赋存背景,古隆起和基底断裂控制了川西坳陷的地质演化,古隆起对油气运移聚集有控制作用,在古隆起控制的范围内,大向斜内的低幅构造具有成藏条件。论文依据大地电磁、地震、重磁、地质与油气等资料,分析了川西前陆构造带油气赋存背景,优选了几个油气有利区块。更多还原

【Abstract】 This peper on the background of Longmen Mountain geological and geophysical structure, premise on magnetotelluric sounding, by study the electrical structure of magnetotelluric sounding profile which across the Longmen Mountain thrust belt and Western Sichuan foreland basin, combination with seismic and geological structure data to study the deep electrical structures of Longmen Mountain thrust nappe, the geometry of main detachment surface, the ancient uplift and depression that may be exist in Western Sichuan foreland basins, basement structure of Western Sichuan Depression and so on,to provide geological and geophysical basis for background research of oil and gas.The Paper Collection Anxian- Suining magnetotelluric data which is section of Songpan - lichuan - Shaoyang geology and geophysics profile,re-process and interpretation. Focus on analysis of curve type to understand the basic electrical layer of this region; analysis of sectional drawings of resistivity and phase to recognizing the overall electrical structure, structure contours,fracture distribution and so on; analysis of the polarization characteristics to understand the structural trend and two-dimensional nature; analysis of total vertical conductance to understand the ups and downs status of the basement; use one-dimensional Bostik transform to determine the depth of the inversion ,provide initial model for the two-dimensional inversion,and use other information supporting constraints to do two-dimensional Occam inversion, inversion mode contains TE, TM and TE + TM inversion, finally,chose the results of joint inversion to interpretation. According to the results of Occam two-dimensional inversion and the magnetotelluric reflection coefficient imaging results to study the Anxian - Suining electrical structure of the upper crust. Based on electrical structure, combined with surface geological observations, divided Anxian-Suining magnetotelluric profile into three electrical structure belt for its electrical structure is different obviously: Longmen Mountain eastern margin electrical structure belt, western Sichuan foreland depression electrical structure belt, central Sichuan electrical structure belt.Study on the characteristics of the three electrical structure belt detailedly. According to the electrical structural characteristics suggested the existence of ancient uplift and depression for the first time.According to Luqu-Longmen Mountain-Zhongjiang magnetotelluric profile, Malcolm-Dujiangyan-Pixian magnetotelluric profile,Anxian - Suining magnetotelluric sounding profile and WFSD-1 AMT profile,the peper analyze of deep electrical structure of thrust nappe structure and geometry of Yingxiu fault which is Longmen Mountain thrust beltthrust nappe structure main detachment surface.Using Luqu-Longmen Mountain-Zhongjiang magnetotelluric profile,Anxian - Suining magnetotelluric profiles and Yingxiu - Jianyang long period magnetotelluric profile, compilation of the basement depth chart of the middle of Western Sichuan foreland basin for the first time,to study structure and buried depth of basement of the basement,for the basement structure controlled the geological evolution of sedimentary cover, and then controlled the deposition of Western Sichuan foreland basin marine strata, to find local uplift structure in the basement is benefit of further search for enabling accumulation environment of oil and gas.According to the ancient uplift of Magnetotelluric profile and basement to study the background of hydrocarbon occurrence, the ancient uplift and basement fractures controlled the geological evolution of western Sichuan depression, the ancient uplift controlled migration and accumulation of oil and gas, within the ancient uplift control, low-amplitude structures of large syncline has reservoir conditions. According to magnetotelluric, seismic, gravity and magnetic, geological and petroleum, etc., analyze of oil and gas occurrence background of the Western Sichuan foreland belt, preferably some hydrocarbon favorable block.更多还原