The phase relations between the first arrivals of compressional and shear waves, and their signification to full wave logging

This paper describes the three phenomena observed in full wave experiments： 1. the amplitudes （absolute value） of the first compressional and shear arrivals have the same variation rules; 2. the phases of the first compressional and shear arrivals are always opposite to each other; and 3. the amplitude variation periods of the first compressional and shear arrivals are 2π. A full analysis and interpretation points out that these phenomena should appear under the full wave logging condition. Hence,the basis of using phase diffrences to extract useful information from the full wave is found.     

声波透射法在混凝土灌注桩完整性检测中的应用

用实例介绍声波透射法在混凝土灌注桩(模型桩)桩身完整性检测中的应用效果,确定缺陷的范围。试验证明,该方法能有效检测混凝土缺陷及其位置。     

煤矿井筒检查孔有关资料处理方法探讨

介绍了利用井筒检查孔资料处理模块处理井筒检查孔有关地质资料、水文地质资料的方法（井筒地层预想柱状图的绘制、井筒岩性切面图的绘制、流量测井资料的处理及有关图件的绘制），其处理成果具有较高的可信度，为井筒开凿及井巷建设提供了可靠的地质与水文地质资料。     

声波测井在煤田勘探中的应用

安鹤煤田伦掌勘探区煤层厚度4—7m，其顶、底板多有薄层泥岩存在。煤层与顶、底板泥岩的声波时差达150μs／m，在测井曲线上表现为相对幅值较高。反映煤层界面的曲线陡直清晰，是该区煤层判别、定性、定厚的重要参数之一。     

新疆准南地区低电阻率油气层测井识别

新疆准南地区吐谷鲁构造油气储层电阻率低，与水层电阻率差异不大。因此，用常规测井解释方法难以对它们作出有效区分。这里先通过对多种测井信息的综合分析，初步摸清测井与不同类别油气储层之间复杂的非线性映射关系，再用神经网络法建模并预测，取得了良好的效果，较好地解决了该区油、气、水层的识别难题。     

A comparison of landslide rates following helicopter and conventional cable-based clear-cut logging operations in the Southwest Coast Mountains of British Columbia

A comparison of landslide rates following helicopter and conventional, cable-based, clear-cut logging was carried out using results from two independent terrain attribute studies in the Eldred and Lois River watersheds in the Southwest Coast Mountains of British Columbia. Landslides initiating from directly within a road prism were excluded from the study in order to focus the comparison on landslides related primarily to conventional versus helicopter yarding methods. A landslide rate of 0.02 landslides/ha was observed in 162 terrain polygons logged by helicopter 8 years prior to this study. Landslide rates in 38 gullied polygons were 0.06 landslides/ha. No landslides were observed in 124 open-slope polygons. Over a similar 8-year average period, 0.03 landslides/ha were observed in 142 cable-yarded terrain polygons; 0.06 and 0.02 landslides/ha occurred in gullied and open-slope polygons, respectively. t-Tests indicate that total landslide rates are not significantly different following helicopter and conventional logging; however, a dichotomy exists between gullied and open-slope terrain polygons. Landslide rates are not significantly different in gullied terrain but are significantly higher on open-slopes following conventional cable logging. Consequently, landslides appear to have a greater potential to occur in open-slope terrain following conventional logging, but differences in gullied polygons are less likely. Increased post-logging landslide rates in conventionally logged, open slopes are more likely the result of undetected road-related drainage changes than differences between helicopter and conventional yarding-related ground disturbance.     

遗传神经网络测井解释技术在宝北区块的应用初探

将遗传算法与人工神经网络(BP网络)的原理结合,对BP网络进行了改进,提高了收敛速度,并防止陷入局部极小。应用改进后的BP算法,建立了针对测井解释的神经网络模型,并应用此模型定量计算了宝北区块的多口井的渗透率值,其解释结果及精度均令人满意。     

测井在永城煤田地质勘探中的应用效果

永城煤田城郊矿区，从普查到精查勘探均开展了测井工作。测井解释的煤层深度、厚度、结构，地质采用率在94．4％以上，测井对划分钻孔岩性，确定物性标志层、断层(点)，提供了可靠的基础资料。     

海底天然气水合物的饱和度预测技术

海底天然气水合物的储量主要取决于水合物的分布面积、水合物稳定带的厚度、沉积层的孔隙度及水合物的饱和度 (或充填率 )等 ,其中水合物在沉积物孔隙中的饱和度对其储量的估计具有重要意义。目前很难通过原地直接测量来获得这种饱和度数据 ,一般根据地球化学或地球物理方法取得。水合物饱和度预测技术主要有 :利用岩心孔隙水氯离子浓度、地球物理测井、地震波速度等间接手段。每一种技术都不是完善的 ,而海底含水合物的沉积物又是一个复杂的系统 ,在预测中应根据实际情况选择比较合适的方法 ,并尽量选择一种以上的方法或模型作多方法校正     

Occurrence of Free-Gas Associated with Methane-Hydrate-Bearing Formations in the MITI Nankai Trough Wells, Offshore Tokai, Japan

Abstract. The MITI Nankai Trough wells were drilled for exploration of methane-hydrate-bearing sediments in association with seismic inferred bottom simulating reflectors (BSRs). In this project, log data showed low velocity compressional-wave (P-wave) layers below methane-hydrate-bearing formations. Dipole shear sonic acoustic tools (DSI) could not acquire accurate compres-sional velocity in this zone, thus it was not possible to accurately correlate between logging, VSP and surface seismic profiles.
Small amount of gas was presumed to cause the problem in obtaining the low velocity P-wave data. VSP interval velocity data was used to assess the DSI inferred low-velocity layer, which showed lower values than the velocity of the drilling muds. Synthetic seismogram was created by VSP-compensated velocity to compare against corridor stack of VSP. As a result, the depths above and below the methane-hydrate-bearing interval were correlated with synthetic seismograms and reflectivity events on the VSP profiles. By using this correlation technique, distribution of methane-hydrate-bearing formations and free-gas-bearing formations can be determined.