摘要
当前基于非结构化四面体网格的正反演技术具有逼近任意起伏地形和特定地质结构的能力.但任意复杂地质模型的四面体网格建立非常困难,制约了该技术在实际勘探中的应用.针对这一难题,我们提出了一种新的复杂地球物理模型的建模和四面体网格离散技术,具有融合数字高程数据、地质剖面图和钻孔数据等地质地理信息的能力.首先,将已知地质地理信息数字化为控制点和线串.然后,利用SKUA-Gocad软件构建高质量三维体积模型,采用Tetgen网格剖分程序进行四面体网格剖分.最后,以安徽泥河铁矿为例,建立了高质量的复杂地球物理模型,并利用我们提出的解析解公式,计算了泥河铁矿产生的复杂重磁场空间分布.计算结果表明:垂向方向的重力场、重力梯度、磁场、磁场梯度都具有高分辨地下异常磁铁矿和硫铁矿水平边界的能力,为了探测该矿深部潜在的密度和磁性矿体,必须精确计算和减去复杂围岩产生的重磁响应.本文提出的建模新技术,不仅可以用于消去矿山已知浅部地质体的干扰,而且可为深部数据反演提供高质量的参考模型,从而提高深部勘探的效果.
Due to the ability to accurately approximate arbitrary undulated topography and complex geological structures, unstructured tetrahedral grids are widely used in geophysical forward modeling and inversion. However, it is difficult to construct tetrahedral grids of arbitrary complex geological model, which restricts its application in practical exploration. To solve this problem, we presented a new technique for establishing and discretizing unstructured tetrahedral grids for complex geophysical models, which can integrate geological and geographic information such as digital elevation data, geological profiles and borehole data. Firstly, the known geological and geographic information were digitized into control points and strings. Then, we used SKUA-GOCAD software to generate a high quality 3 D volume model, and tetrahedral grids were divided by TetGen program. Finally, we take the Nihe iron deposit as an example and constructed a high quality complex geophysical model of the deposit. And we used the developed closed-form formula of mine to calculate the complex gravity and magnetic field generated by the iron deposit. The results show that the vertical gravity field, gravity gradient, magnetic field and magnetic field gradient all can identify the horizontal boundary of underground abnormal magnetite and pyrite clearly. In order to detect the potential density and magnetic orebody in the deep of the deposit, it is necessary to accurately calculate and subtract the gravity and magnetic response generated by the complex surrounding rock. The new technology proposed in this paper can not only be used to eliminate the disturbance of known shallow geological bodies, but also provide a high-quality reference model for deep data inversion, thus improving the effect of deep exploration.
作者
任政勇
王祥
汤井田
吴启红
REN ZhengYong;WANG Xiang;TANG JingTian;WU QiHong(Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring Ministry of Education,Central South University,Changsha 410083,China;Hunan Key Laboratory of Nonferrous Resources and Geological Hazards Exploration,Changsha 410083,China;School of Geosciences and Info-physics of Central South University,Changsha 410083,China;School of Architecture and Civil Engineering of Chengdu University,Chengdu 610106,China)
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2022年第10期3986-3996,共11页
Chinese Journal of Geophysics
基金
国家自然科学基金委优秀青年基金项目(41922027)
国家自然科学基金重点项目(41830107)
中南大学中央高校基本科研业务费专项资金(512191035)联合资助。
