摘要
井巷环境相比于地面来说,更容易使物探传感器接近目标异常体,在井巷中进行地球物理勘探,可以提高发现异常的能力.本文采用高精度快速三维重力场模拟算法,研究了钻孔、巷道周围密度异常体的剩余重力异常特征,并分析了钻孔侧向目标体的产状以及观测点上方或下方异常体的判别方法.模型算例表明:(1)井中微重力方法可以发现井旁一定范围的隐伏密度异常,且重力值明显;(2)井中重力异常极大值与极小值的绝对值大小可以帮助确定异常体倾向,异常绝对值越大,越靠近井轴,否则远离井轴;极值点之间的距离可以确定异常体在深度方向的延伸长度;(3)巷道中下方盈余质量或上方亏损质量会产生相同类型的重力高异常曲线,本文提出通过垂直梯度观测方式来区分异常体的属性,物理依据是:当观测点位于盈余质量之上时,随着观测点靠近目标体,重力异常增大,否则相反.以上研究结果将为未来在复杂井巷环境下开展微重力探测工作提供理论基础.
Compared to earth surface,the geophysical instruments working in well lanes are closer to the anomalous bodies which can improve the ability of finding anomalies.In this paper,we study the gravitational characteristics of anomalies existing surrounding the drills or lanes by using fast and high-precision gravity modeling approach.Several significant conclusions are obtained:(1) Borehole microgravity method can be adopted to detect the insidious gravity anomalies,and the value of gravity anomaly body is apparent;(2)The absolute difference between maximum and minimum values can be used to determine the tendency of anomalies.The bigger the abnormal value is,the anomalous body is closer to the hole axis;Otherwise,the anomalous body is far away from the hole axis.The distance between maximum and minimum values can be used to determine the vertical depth of the anomalies;(3)The responses of the anomalies under the lanes or above the lanes might be similar,which can be distinguished by using the vertical component of the gravity gradient.This is because when the observation sites are above the anomaly body,with the distance between the observation site and the anomaly body becoming closer, the gravity anomaly increases;otherwise,the gravity anomaly decreases.The above study can provide theory basis for further microgravity detection in well lanes.
作者
强建科
李俊营
鲁凯
朱裕振
毛先成
QIANG Jian-ke;LI Jun-ying;LU Kai;ZHU Yu-zhen;MAO Xian-cheng(School of Geoseiences and lnfo-Physics,Central South University,Changsha 410083,China;Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environmental Monitoring (Central South University),Changsha 410083,China;Shandong Provinctal Research Institute of Coal Geology Planning and Exploration,Jinan 250104,China)
出处
《地球物理学进展》
CSCD
北大核心
2018年第6期2575-2580,共6页
Progress in Geophysics
基金
国家自然科学基金项目(41472301)
国家重点研发计划课题(2017YFC0602204-10)资助
关键词
三维重力正演模拟
井中微重力
巷道微重力
积分方程法
3D gravity forward modeling
borehole microgravity
lane microgravity
integral equation method
