松辽盆地综合地球物理剖面地质解释

发布时间：2018-04-17 08:04

本文选题：综合剖面解释 + 韧性剪切带　；参考：《吉林大学》2017年硕士论文

【摘要】：松辽盆地含有丰富的油气资源,为国家的经济建设做出了很大贡献。近几年,浅层油气储量日渐衰退,人们提出了寻找深部油气资源的目标。然而,松辽盆地的地质与地球物理研究大多针对于浅部地层进行的,深部地质的研究尚显不足。而且,深部地层的研究工作采用的也多是单一的地球物理方法,所开展的重-磁-电-震综合地质解释工作较少。针对松辽盆地综合地球物理剖面解释这一目的,本文搜集了松辽盆地基底岩石的重磁特征与电性特征,在充分调查了松辽盆地的地质与地球物理概况的基础上,开展了重-磁-电-震综合剖面研究工作。对于大地电磁测深剖面的研究,本文首先使用了高阻边缘盆地模型和低阻边缘盆地模型分别与水平层状模型的正演模拟对比,来检验松辽盆地的低阻特征是否受盆地边缘电阻的影响。然后研究了大地电磁二维OCCAM反演方法。对于重磁反演剖面的研究,本文首先进行了低密度与高密度异常体同时存在的二维重力异常正演模拟,然后研究了块状异常体、层状介质和阶梯状模型的理论试算,以检验正则化平滑约束反演方法的可靠性。本文做了重力、磁力和大地电磁测深数据的二维反演工作,分别获得了密度、磁化率和电阻率的反演剖面,将它们与地震剖面的综合研究发现,松辽盆地的重力异常、磁力异常、电性异常以及波速特征呈现良好的对应关系。密度与磁化率结构分层性较好,浅层密度差异不大,重力异常主要受基底密度差异的影响。通过磁化率反演剖面研究发现,浅层与深层磁性较高,中间的古生代地层没有磁性。通过电阻率反演剖面的研究发现,很多剖面的中间层电阻率很低,结合地震剖面的研究,本文推断这主要是因为变质核杂岩上拱,其顶部在岩浆运移的拖拽作用下发育为一系列以糜棱岩为特征的韧性剪切带,在钻井岩心中也确实发现了大量的糜棱岩。通过重-磁-电-震综合剖面解释的研究发现,综合使用多种地球物理反演方法,可以有效的降低反演多解性,提高了反演结果的可靠性。
[Abstract]:Songliao Basin is rich in oil and gas resources and has made great contribution to national economic construction.In recent years, shallow oil and gas reserves are declining day by day, people put forward the goal of looking for deep oil and gas resources.However, the geological and geophysical studies of Songliao Basin are mostly aimed at shallow strata, and the deep geological research is still insufficient.Moreover, the research work of deep strata mostly adopts single geophysical method, and the comprehensive geological interpretation of gravity, magnetism, electricity and earthquake is less than that of gravity, magnetism, electricity and earthquake.Aiming at the purpose of comprehensive geophysical profile interpretation of Songliao Basin, this paper collects the gravity and magnetic characteristics and electrical characteristics of the basement rocks in Songliao Basin, and on the basis of a thorough investigation of the geological and geophysical situation of the Songliao Basin,The study of gravity-magnetic-electro-seismic profile is carried out.For the study of magnetotelluric sounding profile, the forward modeling of high resistivity marginal basin model and low resistivity marginal basin model and horizontal stratified model are first used in this paper.To test whether the characteristics of low resistance in Songliao Basin are affected by the resistance of the basin margin.Then the magnetotelluric two-dimensional OCCAM inversion method is studied.For the study of gravity and magnetic inversion profile, the forward modeling of two-dimensional gravity anomaly with both low density and high density anomaly is carried out in this paper, and then the theoretical calculation of block anomaly, stratified medium and stepped model is studied.To verify the reliability of regularized smoothing constraint inversion method.In this paper, the inversion of gravity, magnetic and magnetotelluric sounding data is done, and the inversion profiles of density, susceptibility and resistivity are obtained respectively.Magnetic anomalies, electrical anomalies and wave velocity characteristics show a good correspondence.The stratification of density and susceptibility structure is better than that of shallow layer. The gravity anomaly is mainly affected by the difference of substrate density.It is found that the magnetic properties of the shallow and deep layers are higher than that of the Paleozoic strata.Through the research of resistivity inversion section, it is found that the resistivity of the middle layer of many sections is very low. Combined with the study of seismic section, this paper inferred that this was mainly due to the arch of metamorphic core complex.The top developed into a series of ductile shear zones characterized by mylonite under the action of magma migration, and a large number of mylonites were found in the core of drilling rocks.Through the study of gravity magnetic-electric-seismic comprehensive profile interpretation, it is found that using multiple geophysical inversion methods can effectively reduce the multi-solution inversion and improve the reliability of inversion results.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P631

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