γ测井资料反褶积分层解释法在8411矿床的试验对比

γ测井资料的反褶积分层解释法具有方法简单,精度高,速度快,分辨能力强,用微机进行计算等优点。作者通过用反褶积法对8411矿床γ测井资料的解释,对视特征参数的选择条件,γ强度底数的确定和划分矿层边界的原则,提出了初步看法。将该法的试验结果与传统的平均含量法和矿心分析结果进行了对比,还分析了视特征参数的取值大小对矿层线储量及矿化分层的影响,并讨论了引起线储量相对误差的原因。     

多分辨率地震信号反褶积

基于二进小波变换提出了一种新的反褶积方法─-多分辨率地震信号反褶积．在地震信号二进小波变换域中的各尺度上分别进行其分辨率随小波尺度变化的反褶积,利用不同分辨率反褶积结果之间的相关性,以及测量噪声随尺度的衰减特性,从低分辨率反褶积结果逼近高分辨率反褶积结果．理论分析和实验表明,该方法有较高的精度,并且在较低信噪比情况下有好的效果．     

地震记录的时间域反褶积、仿真及在地震计方位角相对测量中的应用

介绍了一种用冲击不变法从速度响应平坦地震计二阶传递函数设计得到的递归滤波方法,比用双线性变换得到的递归滤波系数少,因此使用更方便.作者用此方法作了反褶积与仿真的数值实验和实际地震记录的短周期仿真试验,仿真结果与实际仪器记录符合较好;并将此法应用于地震计方位角的相关分析法相对测量,结果与不仿真的相关分析测量相比更接近寻北仪的绝对测量结果.     

Multiscale anisotropic diffusion for ringing artifact suppression in geophysical deconvolution data

Ringing artifact degradations always appear in the deconvolution of geophysical data. To address this problem, we propose a postprocessing approach to suppress ringing artifacts that uses a novel anisotropic diffusion based on a stationary wavelet transform (SWT) algorithm. In this paper, we discuss the ringing artifact suppression problem and analyze the characteristics of the deconvolution ringing artifact. The deconvolution data containing ringing artifacts are decomposed into different SWT subbands for analysis, and a new multiscale adaptive anisotropic filter is developed to suppress these degradations. Finally, we demonstrate the performance of the proposed method and describe the experiments in detail.     

接收函数方法研究进展

远震P波波形数据中包含了大量的地震台站下方地壳和上地慢速度间断面所产生的PS转换波及其多次反射波的信息，由此提取的接收函数是了解地壳上地慢速度精细结构的重要步骤之一。本介绍了目前在提高接收函数结果的稳定性和精度方面的研究进展，包括石油勘探中一些成熟的地震反射处理方法逐步渗透到接收函数的研究领域。这些处理方法以前所未有的分辨率展示了地壳上地幔结构的横向非均匀性。     

Retrieval of atmospheric reflectivity profiles in case of long radar pulses

Future space-borne cloud profiling radars (CPR) will employ longer pulse lengths than ground-based systems. As a consequence, reflectivity profiles observed from space will be more strongly convoluted with the radar pulse shape. Here we describe a constrained linear inverse technique that reduces the effects of this convolution. We apply the technique to simulated data, based on actual observations from the ground, and show that significant improvements in the reflectivity profile can be obtained. Average Z errors (dBz) are halved, while cloud boundaries are substantially better retrieved. The results in this paper are relevant to space-borne missions like CloudSat and EarthCARE.     

ENHANCING THE DECONVOLUTION OF NOISY CHROMATOGRAPHIC DATA BY JANSSON''S METHOD

In previous papers Jansson's method was found to be successful at deconvolving severely overlapped gaschromatographic peaks.In the most recent paper the method was evaluated with respect to quantitativeaceuracy,peak area and retention time repeatability.The problems associated with deconvolving noisydata and some alternatives which can improve the ability of Jansson's method to deconvolve noisy dataare discussed.These alternatives include presmoothing the data with a nine-point,third-order polynomialfilter and data reblurring.This paper will test these methods on peaks with various degrees of resolutionand signal-to-noise ratios.     

L1 norm inversion method for deconvolution in attenuating media

In order to perform a good pulse compression, the conventional spike deconvolution method requires that the wavelet is stationary. However, this requirement is never reached since the seismic wave always suffers high‐frequency attenuation and dispersion as it propagates in real materials. Due to this issue, the data need to pass through some kind of inverse‐Q filter. Most methods attempt to correct the attenuation effect by applying greater gains for high‐frequency components of the signal. The problem with this procedure is that it generally boosts high‐frequency noise. In order to deal with this problem, we present a new inversion method designed to estimate the reflectivity function in attenuating media. The key feature of the proposed method is the use of the least absolute error (L1 norm) to define both the data and model error in the objective functional. The L1 norm is more immune to noise when compared to the usual L2 one, especially when the data are contaminated by discrepant sample values. It also favours sparse reflectivity when used to define the model error in regularization of the inverse problem and also increases the resolution, since an efficient pulse compression is attained. Tests on synthetic and real data demonstrate the efficacy of the method in raising the resolution of the seismic signal without boosting its noise component.     

Multi‐transient electromagnetic repeatability experiment over the North Sea Harding field‡

We present results of synthetic time‐lapse and real repeatability multi‐transient electromagnetic surveys over the North Sea Harding field. Using Archie's law to convert porosity and fluid saturation to resistivity we created 3D isotropic models of the reservoir resistivity at different stages of production from the initial state in 1996 through to complete hydrocarbon production by 2016 and, for each stage, we simulated an east‐west transient electromagnetic survey line across Harding. Unconstrained 1D full‐waveform Occam inversions of these synthetic data show that Harding should be detectable and its lateral extent reasonably well‐defined. Resistivity changes caused by hydrocarbon production from initial pre‐production state to production of the oil rim in 2011 are discernible as are significant changes from 2011–2016 during the modelled gas blowdown phase. The 2D repeatability surveys of 2007 and 2008 tied two wells: one on and the other off the structure. Between the two surveys the segment of the field under investigation produced 3.9 million barrels of oil – not enough to generate an observable time‐lapse electromagnetic anomaly with a signal‐to‐noise ratio of 40 dB. Processing of the 2007 and 2008 data included deconvolution for the measured source current and removal of spatially‐correlated noise, which increased the signal‐to‐noise ratio of the recovered impulse responses by about 20 dB and resulted in a normalized root‐mean‐square difference of 3.9% between the data sets. 1D full‐waveform Occam inversions of the real data showed that Harding was detectable and its lateral extent was also reasonably well‐defined. The results indicate that the multi‐transient electromagnetic method is suitable for exploration, appraisal and monitoring hydrocarbon production.     

由精密控制人工震源观测到的绵竹5.6级地震前后波速变化

地震危险区断层的应力状态变化及其精确测量一直是地球物理学关注的热点问题之一,主动震源探测技术的发展为解决上述问题带来了可能.汶川大地震后,结合汶川地震断裂带科学钻探,在四川省绵竹市九龙镇--跨越龙门山断裂带前山断裂,利用10 t精密控制人工震源进行了连续监测试验,在试验观测期间的2009年6月30日凌晨2时3分,当地发生了M_s5.6级地震,地震前后观测数据的对比分析表明,该地震发生前后,穿过断裂带的直达S波走时发生了时延为5~9 ms的微弱变化,射线路径上的平均波速相对下降了约0.3%,该时延主要是由地震同震效应引起的断裂带内应力调整和物性变化造成的.所使用的精密控制人工震源性能稳定,适于开展断层监测.这一结果对于发展断裂带主动震源动态监测技术具有重要意义.