摘要
塔里木盆地塔西南山前带地表条件恶劣,且发育厚度不等的黄土层,致使浅层低降速带难以查清,地震静校正问题严重;另外,由于地表复杂,存在局部电性不均匀体,大地电磁(MT)资料静位移现象也较普遍。考虑到瞬变电磁法(TEM)浅层电性分辨率高、不受静位移影响的特点,在该区部署了TEM表层调查和同点位的三维MT勘探,目的是揭示表层黄土层的分布特征及变化趋势,以辅助地震进行浅层速度建模和静校正,同时也可为MT资料静校正提供参考。结果表明:利用TEM资料对三维MT资料进行静校正,改善了静校正效果,为三维MT更好地解决构造问题提供了条件;利用TEM反演结果预测了西部山前带黄土层的厚度分布,且预测厚度与微测井厚度相差小于5m。
The topography of foreland thrust zones in southwest part of Tarim Basin is rather complicated.Thick and unequal loess layers cause serious problems for seismic static corrections.On the other hand,local electrical inhomogeneous bodies in the complex surface bring another problem:static shift in magnetotelluric(MT)data is common.Since transient electromagnetic method(TEM)can get high resolution data in shallow area without static shifts,a TEM was deployed at the same time and site as a 3D MT exploration was conducted.The purpose of this TEM is to reveal the distribution and tendency of the loess layers,to provide the basis of shallow velocity model building for seismic static corrections,and to give references for MT static corrections.As a result of the TEM data,the static shift in 3D MT data is well suppressed,which provides great help for 3D MT structure interpretation.Furthermore,the thickness distribution of the loess layer in piedmont of western mountains is delineated with the TEM inversion result,and loess layer thickness calculated on TEM data and uphole data is similar.
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2016年第S1期131-136,10,共6页
Oil Geophysical Prospecting
基金
国家重大科技专项(2016ZX05018006-001)资助
关键词
TEM
黄土层
MT
静校正
transient electromagnetic(TEM)
loess layer
magnetotelluric(MT)
static shift correction
