孤北21三维目标处理实例

结合地质目标及处理要求,对孤北21井区三维资料进行了分析。对不同处理目标采取了相应的处理措施,取得了较好的处理效果。     

瞬变电磁测深法的研究深度

研究发现,瞬变测深法研究深度除了与采样时间(采样间隔,起始和终止采样时间等)有关外,还与信号源强度、大地电导率、系统噪音水平以及仪器观测精度等因素有关,文中对研究深度与这些量之间的关系作了数学描述。     

航磁ΔT解析信号确定线性构造隐伏形态的算法及阿尔金的应用

本文研究了模拟线性地质构造具有普遍意义的有限延深薄板状体ΔＴ的解析信号强度与其几何参数之间的超定方程关系,运用奇异值分解和广义逆技术求解超定方程,获得了高精度的理论反演方法,同时给出了定性解释板状体产状的辅助方法。对阿尔金地区隐伏断裂形态的反演结果,为西藏地体的“北推东移”提供了定量化的地球物理解释证据。文章还勾画了阿尔金与塔里木的深部界线。     

陆域冻土区地震探测信号提取技术——以青海哈拉湖地区为例

青海哈拉湖地区的陆域冻土区天然气水合物,其埋藏深度较浅,地震有效信号往往被干扰波淹没,如何从复杂的地震波场里有效提取出与地层、水合物有关的地震反射信号是开展地震资料精细解释和天然气水合物预测工作的前提.为此,详细分析青海哈拉湖地区地震探测原始数据,总结该地区干扰噪声的类型及特点,制定地震信号提取流程,并在叠前道集上逐步采用有针对性的噪声衰减、振幅补偿、反褶积以及叠加等处理技术,压制各类干扰信息,最大程度地保留有效反射信号,提高地震资料的分辨率、信噪比和保真度,更好地为地震资料解释和有利储层预测服务.     

Electromagnetic signals associated with stick–slip of quartz-free rocks

We recorded clear transients in the electric and magnetic fields upon sudden slip in stick–slip experiments on dry, cylindrically shaped, quartz-free rock specimens of basalt and peridotite with a 30° saw-cut (representing a fault) at confining pressures of up to 120 MPa. The amplitudes of the measured electric field signals were always higher at the electrode pair oriented parallel to the strike of the fault than at the pair oriented perpendicular. This anisotropy suggests a preferred electric polarization normal to the slip surface. The transients in the electric and magnetic fields were observed only when the fault slip occurred by stick–slip mode, not by a stable mode of the sliding, and the amplitudes of the electric field signals increased with increasing stress drop. It is suggested that the generation process of the electromagnetic signals is closely related to the characteristic behavior of the fault at the time of the initiation of slip during stick–slip events, probably with respect to the intensity of the signals. We propose that one or both of the following two processes characteristic of the fault at the time of the initiation of slip during stick–slip events are essential for the generation of detectable electromagnetic signals: rapid slip along the simulated fault and separation of the rock masses across the fault.     

主成分分析在航空瞬变电磁去噪中的应用

由于航空瞬变电磁二次场数据是一种宽频带信号且幅度较小,因此常常受到随机噪声、天电噪声以及人文噪声的影响。研究针对上述噪声的去噪方法,可以提高处理和解释的精度。这里给出了基于主成分分析的航空瞬变电磁去噪方法,首先应用主成分分析方法对叠加抽道后的单测点衰减曲线进行分解,然后应用曲线趋势对比法和L曲线法对分解后的成分进行分析,确定出有效信号成分,最后使用这些有效信号成分进行重构,从而达到抑制噪声的目的。模拟信号分析以及实测数据的实验结果表明,应用主成分分析法处理航空瞬变电磁数据,在保持反映地下介质分布的有效信号幅度基本不变的条件下,能有效抑制天电噪声和人文噪声,为保幅处理和解释奠定了良好的基础。     

海河流域严重干旱500hPa信号场异常信号分析

基于严重少雨旬的定义,分析海河流域1961～2009年严重少雨旬的分布特征,进而对汛期40个典型严重少雨旬的500hPa信号场进行经验正交分解(EOF分析).结果表明:EOF第一模态的方差贡献率达到35.3％,远高于其他模态;第一模态呈现出2个负异常区和1个正异常区,在对应的环流背景下,海河流域受暖性高压控制,高纬冷空气及低纬暖湿气流难以到达流域上空交绥,持续高温少雨造成流域严重干旱.     

核脉冲信号数字高斯成形模型的建立与仿真

详细阐述了一种以Sallen—Key滤波器为基础的新型数字高斯成形的方法。运用二阶微分方程建立高斯成形数学模型,在模型解算过程中利用数值微分算法得到一个通用的输入信号与输出信号的数值递推解,从而实现了核脉冲信号的数字高斯成形。通过标准指数信号的模拟以及实际测量信号的模拟,确定了数字高斯成形的参数。     

2D stabilised analytic signal method in DC pole-pole potential data interpretation

Using analytic signal method, interpretation of pole-pole secondary electric potentials due to 2D conductive/resistive prisms is presented. The estimated parameters are the location, lateral extent or width and depth to top surface of the prism. Forward modelling is attempted by 2D-Finite Difference method. The proposed stabilised analytic signal algorithm (RES2AS) uses Tikhonov’s regularization scheme and FFT routines. The algorithm is tested on three theoretical examples and field data from the campus of Roorkee University. The stability of RES2AS is also tested on synthetic error prone secondary pole-pole potential data.     

参量阵浅地层剖面测量技术 在近岸海洋工程的应用效果

介绍了海底浅地层声学探测技术的发展情况, 简述了新型参量阵声纳探测的原理和特点, 通过SES-96参量阵测深或浅地层剖面系统在山东半岛海区的应用实例, 对此新型参量阵声纳技术的应用效果进行了分析评价。