三维物探资料在镇巴区块地质研究中的应用

发布时间：2018-06-10 09:52

本文选题：三维反演 + 推覆构造　；参考：《长江大学》2015年硕士论文

【摘要】：由于镇巴地区地形起伏大,山坡陡峻属中高山区,施工十分困难,导致地震地质资料不完善难以确定构造模式,而电法勘探具有仪器轻便,施工容易成本低的优点,故此次利用以电法勘探为主,结合重力、磁力、地震资料对工区进行地层特征,构造模式,生储盖组合以及储层油藏特征描述的地质综合解释。对于重力资料的处理利用统一公式进行4项改正：正常场改正、地形校正、中间层校正以及高程项校正。其中中间层和地形改正中的地壳密度用变密度法。而重力资料的反演,正演直接用三重积分法,反演采用遗传算法。对于磁力资料的处理：进行了正常场改正和日变改正两项校正。而磁法三维约束反演是三维线性矢量的问题。正演直接用三重积分法,反演采用模拟退火法。其中剩余磁化强度大小和方向要由实验室磁性测定获得。测井和地震资料主要用于对特定的地层进行界面限定。对于电法资料的处理是本文的重点,资料的处理涉及三维静校正和三维地形模拟；静位移校正技术：采用张量阻抗分解法；地形处理方法是融入带地形的反演中。由于本测区为三维构造发育地区,无疑进行三维反演是最为科学合理的。正演算法为基于张量格林函数的体积分方程法,反演则用降维逼近反演法,反演过程将地形因素融入其中。降维逼近法的反演原理是对初始模型进行3D正演,结合实测的视电阻率获取类一维视电阻率,再对类一维视电阻率作一维形式化反演,形成新的模型,继续进行下一轮迭代。综合地质、地震、重磁和电法资料,着重分析各个电性异常的平面特征。深入研究冲断带结构关系、断裂发育状况及其展布特征,对镇巴地区构造进行了平面的解释。划分出了五大物性层,解译出六条断裂。划分出三个一级构造单元,即北大巴山推覆构造带、米仓山—南大巴山冲断构造带、四川盆地；划分出五个二级构造单元,即紫阳推覆体、镇坪推覆体、高滩推覆体、大巴山南缘冲断带、南大巴断褶带。综合解释圈定研究区域局部构造四个,根据电阻率特征,对构造进行评价确定两个最有利构造。
[Abstract]:Due to the large topography and steep hillsides in Zhenba area, which is very difficult to construct, it is difficult to determine the structural model because of the imperfection of seismic and geological data, and the electric exploration has the advantages of portable instruments and low construction cost. Therefore, the geological comprehensive interpretation of stratigraphic characteristics, structural model, source, reservoir and cap assemblage and reservoir characteristics description of the working area is carried out by using electrical exploration, combined with gravity, magnetic force and seismic data. For gravity data processing, four corrections are made by using the unified formula: normal field correction, topographic correction, intermediate layer correction and elevation correction. The crustal density in the intermediate layer and topographic correction is determined by variable density method. The forward inversion of gravity data is based on the triple integration method and the genetic algorithm is used in the inversion. For the processing of magnetic data, two corrections, normal field correction and diurnal correction, are carried out. The three-dimensional constrained inversion by magnetic method is a problem of three-dimensional linear vector. The forward modeling is directly based on the triple integration method, and the simulated annealing method is used for the inversion. The magnitude and direction of residual magnetization should be obtained by laboratory magnetic measurement. Logging and seismic data are mainly used to define the interface of a particular formation. The processing of electrical data is the focus of this paper, the data processing involves three-dimensional static correction and three-dimensional terrain simulation; static displacement correction technology: using Zhang Liang impedance decomposition method; terrain processing method is integrated into the inversion of terrain. Since this area is a three-dimensional tectonic area, it is undoubtedly the most scientific and reasonable to carry out three-dimensional inversion. The forward algorithm is a volume fractional equation method based on Zhang Liang Green's function, and the inversion is based on the reduced dimension approximation inversion method, in which topographic factors are incorporated into the inversion process. The inversion principle of the reduced-dimension approximation method is to carry out 3D forward modeling of the initial model, combining with the measured apparent resistivity to obtain one-dimensional apparent resistivity, and then to make one-dimensional formal inversion of the quasi-one-dimensional apparent resistivity, to form a new model, and to continue the next iteration. Based on geological, seismic, gravity, magnetic and electrical data, the plane characteristics of various electrical anomalies are analyzed. In this paper, the structural relationship, fault development and distribution characteristics of thrust zone are studied, and the structure of Zhenba area is explained in plane. Five physical layers were divided and six faults were interpreted. It is divided into three primary tectonic units, namely, the North Dabashan nappe belt, the Micangshan-South Dabashan thrust tectonic belt, the Sichuan basin, and the five secondary tectonic units, namely, the Ziyang nappe, the Zhenping nappe, the Gaotan nappe, The southern margin of Daba Mountain thrust belt, South Daba fault fold belt. There are four local structures in the area studied by comprehensive interpretation and delineation. According to the characteristics of resistivity, the two most favorable structures are determined by evaluating the structures.
【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631;P618.13

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