耦合地震约束信息的重磁电联合反演方法及其应用——以塔里木盆地深层地质结构解析为例  

Gravity-magnetic-magnetotelluric joint inversion method coupled with seismic constraint information and its application:Case study of the analysis of deep geological structure in Tarim Basin

作　　者：杨敏[1] 于鹏[2] 朱光有[1] 张罗磊[2] 闫磊[1] 赵崇进 马德波[1] 陈志勇[1] YANG Min;YU Peng;ZHU Guangyou;ZHANG Luolei;YAN Lei;ZHAO Chongjin;MA Debo;CHEN Zhiyong(PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China;College of Marine Geology and Geophysics,Tongji University,Shanghai 200091,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]同济大学海洋与地球科学学院,上海200091

出　　处：《天然气地球科学》2022年第1期168-179,共12页Natural Gas Geoscience

基　　金：中国石油天然气股份有限公司重大科技项目“深层烃源岩形成与分布”(编号:2018A-0102);“古老碳酸盐岩油气成藏分布规律与关键技术”(编号:2019B-04);国家自然科学基金项目“下寒武统黑色页岩中汞含量异常及其对烃源岩形成环境的指示”(编号:42073068)联合资助。

摘　　要：近年来,塔里木盆地新元古界—寒武系深层成为风险勘探和地质研究关注的焦点和热点。由于盆地8000 m以深深层地震资料品质差,地层展布及厚度、断裂分布等认识不清楚,制约了对深层勘探领域的评价。以塔里木盆地内的重力数据、磁力数据以及大地电磁数据为基础,结合地表露头、钻井、地震等资料,建立了耦合地震约束信息的重磁电三维联合反演方法,实现了对塔里木盆地深部6~10 km储层的物性结构进行准确刻画;解决了盆地深部古老地层的残余厚度展布、深大断裂发育情况以及盆地不同区块现今地温梯度差异大等地质问题,为塔里木盆地下一步深层勘探提供方向。研究认为:塔里木盆地震旦系—南华系具有相对低—中阻、弱—中等磁性和低密度的物性特征,地层残留厚度主要分布在盆地东北、西南2个方向,其残留厚度范围为500~4500 m,与目前地震资料预测的厚度相吻合;盆地基底主要发育北东东向、北西向、近东西向3个方向的深大断裂,其控制了盆地“四隆五坳”构造格局和震旦系—南华系残留地层分布;塔里木盆地不同块体地温梯度的差异性与磁性层底(居里面)深度密切相关,同为隆起区,古城地区磁性层底埋深相对于塔中、塔北较浅,但其地温梯度最高。In recent years,deep formations of Neoproterozoic-Cambrian in Tarim Basin have become the focus and hotspot of risk exploration and geological studies. Due to the poor quality of seismic data in the depth below 8 000 m of the basin,the formation distribution,thickness and faults distribution are not clear,which restricts the evaluation of the deep exploration area. Based on gravity data,magnetic data and magnetotelluric data collected in the basin,combined with geological data such as outcrop,drilling and seismic data,a three-dimensional joint inversion method for gravity,magnetic and magnetotelluric data is established coupled with conventional seismic information. The method can accurately characterize the physical structures in depths of 6-10 km,and can be used to solve the geological problems such as residual thickness distribution in deep ancient strata,the development of deep faults and the great difference of the present geothermal gradients in different parts of the basin,providing directions for further deep exploration in the Tarim Basin. It is shown that the Sinian to Nanhuan systems in Tarim Bbasin have the characteristics of relatively low-medium resistivity,weak-medium magnetism and low density,of which residual thickness is mainly distributed in the northeast and southwest directions of the basin,and the residual thickness ranges from 500 m to 4 500 m,which is consistent with the current seismic data. In the basement of the basin mainly develop deep faults in north-east-east,north-west,and near east-west directions,which control the structural pattern of the "Four Uplifts and Five Depressions" in the basin and the distribution of Sinian-Nanhuan residual strata;the difference of geothermal gradients of different blocks in Tarim Basin is closely related to the bottom depth of the magnetic layer. Of the uplift areas,the bottom depth of the magnetic layer in the Gucheng area is shallower than that in Tazhong area or Tabei area,but its geothermal gradient is the highest.

关 键 词：深层 重磁电震联合反演 南华系—震旦系 地温梯度 塔里木盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]