PROTEM67D系统在探测深部富水异常中的应用

通过瞬变电磁法在平顶山西南部矿区探测主采煤层顶、底板富水异常区的成功实例,探讨PROTEM67D系统在探测埋深大于1000m地质体时的应用效果。认为在外业数据采集前,通过试验选择合适的工作参数,是完成深部异常体勘探的前提条件和重要保证。     

硬岩型铀矿化(点、带)地球物理特征

为了深入研究硬岩型铀矿化(点、带)的地球物理特征,在桃山、红山子地区开展了综合物探测量.结果表明,在△T磁异常平面等值线图中,铀矿床(点、带)一般位于强弱磁异常过渡地带偏弱磁异常一侧,电阻率断面图中多位于高低阻梯度变化带或中低阻区,电阻率平面图中多位于中低阻过渡带偏低阻一侧.该硬岩型铀矿化地球物理特征为寻找该类铀矿有利地段提供了重要信息.     

吉林省磐石市烟筒山镇碱场膨润土矿测量技术及应用

在地质学科领域中,地质调查和矿产勘查是地质学科最基本的要素,是地质学的基础。测量技术作为一种重要的地质勘查辅助手段,贯穿着整个地质成果的全部过程,在地质勘查工程的发展起到了关键性作用。本文论述了吉林省磐石市烟筒山镇碱场膨润土矿地质勘查工作,测量技术的应用成果。     

三维地质建模软件发展现状及问题探讨

分析了三维地质建模软件可以明显地提高工作效率与工程质量,建立勘探区的三维地质模型,检查原始数据的正确性,通过各种“虚拟切割”手段检查各种地质要素间的相互关系。探讨了三维地质建模软件开发中所存在的几个问题,包括软件开发团队应适时转为公司机制,审慎选择开源工具,三维地质建模的三维模型数据标准,在勘探规范中增加三维地质建模要求,二、三维联动编辑,选准产品的用户群的与盈利模式等。     

强随机噪声条件下时窗类型局部线性化对TFPF技术的影响

为了更广泛地应用时频峰值滤波方法消减地震勘探记录中强随机噪声,本文比较详细地探讨了该方法在应用时需要处理的时窗选取、一个时窗内局部线性化等主要基础技术问题.经过时变时窗的仿真计算,运用多项指标比较,包括整体背景强弱、振幅谱、信噪比、均方误差、有效子波波峰波谷幅值、畸变程度,综合评价出（L₀+L_x）时窗滤波的效果较理想.对于三角波这类简单类型的周期波,其时频峰值滤波效果与边线段平均曲率变化、时窗长度等条件有关,即三角波边线段平均曲率越大,滤波结果的均方误差越大;另外,边线段平均曲率增大时,选取的时窗长度有变小的趋势.总之,在地震勘探中应用时频峰值滤波方法消减强随机噪声时,一方面要合理地选取时窗参数,另一方面时窗参数又不能变化过大,以避免对有效子波波形产生畸变影响.     

Aeromagnetic and Landsat TM structural interpretation for identifying regional groundwater exploration targets, south-central Zimbabwe Craton

Aeromagnetic (AM) and Landsat Thematic Mapper (TM) data from the south-central Zimbabwe Craton have been processed for the purpose of regional structural mapping and thereby to develop strategic models for groundwater exploration in hard-rock areas. The lineament density is greater on TM than on AM images, partly due to the resolution of the different datasets, and also because not all TM lineaments have a magnetic signature. The derived maps reveal several previously undetected lineaments corresponding to dykes, faults, shear zones and/or tectonically-related joints, striking predominantly NNE, NNW and WNW. We suggest the possible hydrogeological significance of some of these patterns as follows: the aeromagnetic data can be used to map faults and fractures of considerable depth which are likely to be open groundwater conduits at depth (typically under tension), while TM lineaments, although not necessarily open (mostly under compression), represent recharge areas.The interpreted persistent lineation and well developed fracture patterns are correlated with existing boreholes and indicate a spatial relationship between regional structures and high borehole yields (> 3 m³/h). This relationship is combined with other lithological and hydrogeological information to identify potential regional groundwater sites for detailed ground investigations. These are defined as dyke margins, faults, fractures/joints or intersections of any combination of these structures. Priority should be given to coincident AM/TM lineaments (e.g., NNW and NNE fractures) and continuous structures with large catchment areas (e.g., NNE and WNW faults). The late Archaean (2.6 Ga) granites are considered the most favourable unit because of their associated long and deep brittle fractures between numerous bornhardts (inselbergs) and kopjes. Several small-scale TM lineaments also form important local sources of groundwater for hand-dug wells. Based on measured rock susceptibilities from the area, we present a model of the typical magnetic responses from the possible groundwater exploration targets. The developed magnetic model could be applicable to similar terrains in other Archaean Cratons.     

3D Gravity Inversion by Growing Bodies and Shaping Layers at Mt. Vesuvius (Southern Italy)

To improve our knowledge of the structural pattern of Mt. Vesuvius and its magmatic system, which represents one of the three volcanoes located in the Neapolitan area (together with Campi Flegrei and Ischia; southern Italy), we analyze here the Bouguer gravity map that is already available through its interpretation by means of 2.5-dimensional modelling. We have carried out a three-dimensional interpretation using a new and original algorithm, known as ‘Layers’, that has been especially processed for this purpose. Layers works in an automatic and non-subjective way, and allows the definition of the structural settings in terms of several layers, each representing a specific geological formation. The same data are also interpreted in terms of isolated and shallow anomalous density bodies using a well tested algorithm known as ‘Growth’. We focus our inversions on the Mt. Vesuvius volcano, while globally analyzing the entire Neapolitan area, in order to investigate the deep structures, and in particular the deep extended ‘sill’ that has been revealed by seismic tomography. The final models generally confirm the global setting of the area as outlined by previous investigations, mainly for the shape and depth of the carbonate basement below Mt. Vesuvius. The presence of lateral density contrasts inside the volcano edifice is also shown, which was only hypothesized in the 2.5-dimensional inversion. Moreover, the models allow us to note a high density body that rises from the top of the carbonate basement and further elongates above sea level. This probably represents an uprising of the same basement, which is just below the volcano and which coincides with the V_P and V_P/V_S anomalies detected under the crater. The three-dimensional results also reveal that the two inversion methods provide very similar models, where the high density isolated body in the Growth model can be associated with the rising high density anomaly in the Layers model. Taking into account the density of these modelled bodies, we would also suggest that they represent solidified magma bodies, as suggested by other studies. Finally, we did not clearly detect any deep anomalous body that can be associated with the sill that was suggested by seismic tomography.     

海域天然气水合物勘测的地球物理方法

到目前为止,已经探明的天然气水合物储量要远小于预测的水合物储量.这种现状不同程度地反映出我们对天然气水合物赋存规律认识不足,和对天然气水合物勘探方法认识不足.本文根据作者多次参加水合物地球物理调查国际航次的认识及文献资料,综述了海域天然气水合物勘探方面一些有效的地球物理技术方法,以利于我国海域天然气水合物的勘探工作以及勘探方法的创新.本文指出,地震勘探是目前进行天然气水合物勘探最常用、也是最重要的方法.地震方法主要包括传统的单道、多道地震方法、高分辨地震方法、深拖多道地震探测方法、海底地震仪方法、多道-多分量海底地震电缆方法、海底地震检波器方法等.此外,根据水合物发育区特有的海底地形地貌特征和水体异常特征,根据水合物发育所需要的温度-压力场特征、电磁特征和含水合物地层的剪切模量特征发展的多波束方法、旁扫声纳方法、海底热流探测方法、海底电磁方法以及海底重力测量方法等都在海域天然气水合物勘探中有着很好的效果.     

海区前新生代残留盆地油气研究的综合地球物理技术

我国前新生代残留盆地油气资源的巨大潜力已为近年的一些勘探实践所证实,但是仍面临许多技术难题.本文介绍了近年在863计划支持下,针对残留盆地油气勘探难题所研究的一些方法与技术.其中包括针对我国海区残留盆地勘探目标的地震采集技术、基于弯曲射线的复杂构造叠前成像技术和残留盆地残余厚度提取技术等.这些技术已在我国海域进行了试验并取得了一定的成效.