含孔隙、裂隙地层随钻多极子声波测井理论          下载免费PDF全文

许松  苏远大  陈雪莲  唐晓明 《地球物理学报》2014,57(6):1999-2012

储层岩石中普遍存在孔隙与裂隙,对钻井中的测井声波产生重要影响.基于孔、裂隙介质弹性波理论,导出了随钻声波测井的井孔声场表达式.据此考察了地层裂隙密度与含气饱和度的变化时井孔内随钻多极子模式波（斯通利波、弯曲波和螺旋波）的速度、衰减与灵敏度以及地层纵、横波的响应特征.裂隙密度与含气饱和度对模式波的速度频散与衰减都有影响,且两参数的值越大,影响越大.具体来说,速度对裂隙密度更敏感,而衰减对含气饱和度更敏感.具有"艾里相"特征的随钻偶极和四极子波在地层含气时产生强烈衰减,可以作为判断地层含气的一个明显指示.理论模拟与实际测井数据分析结果符合较好.  相似文献   

钙质砂的休止角研究与工程应用     

金宗川 《岩土力学》2018,39(7):2583-2590

砂土的天然休止角对土堆设计、基坑设计和边坡稳定性研判有重要的指导意义。砂土的天然休止角受土颗粒的摩擦特性、颗粒形状、粒径和含水状态等诸多因素的影响。开展了钙质砂的天然休止角试验,研究了多种因素对钙质砂天然休止角的影响规律。结果表明：钙质砂3种常见颗粒形状中,片状休止角最大,枝棒状次之,块状最小;钙质砂天然休止角随着粒径的增大而增大;当平均粒径相同时,天然休止角随着不均匀系数的增大而增大,随着曲率系数的增大而减少;通过与标准石英砂的对比试验发现,石英砂的天然休止角小于钙质砂天然休止角。对现场钙质砂边坡测量后表明,钙质砂地基经过振冲挤密后基坑开挖最大坡角略大于室内测得的天然休止角。研究结果对钙质砂土堆和基坑设计等工程实践有一定指导意义。  相似文献   

饱和冻土中弹性体波传播特性影响参数研究     

仇浩淼  夏唐代  郑晴晴  周飞 《岩土力学》2018,39(11):4053-4062

基于Leclaire对饱和双相孔隙弹性介质Biot模型的扩展,研究含有两种不同固相组分的三相多孔弹性介质中体波的传播特性。以饱和冻土为例,分析了各相体积分数、颗粒形状,接触参数等因素对波动方程中惯性参数、黏性参数、刚度参数的影响;对该三相介质模型进行了退化,分析了孔隙中只含液态水或固态冰时体波的特性;以饱和冻土为例,通过数值计算,探讨了饱和冻土中体波的相速度和衰减系数与胶结参数、接触参数、频率、饱和度、孔隙率等参数的关系。结果表明：与一般的饱和土不同,饱和冻土中存在5种体波,即3种纵波和2种横波;5种体波均具有弥散性和衰减性,且P1波、S1波弥散性和衰减性远小于P2、P3、S2波;胶结参数、饱和度、孔隙率对5种体波的传播特性影响显著,接触参数对传播特性影响较小。  相似文献   

天然气水合物区多相流体运移模型：以南海神狐海域为例          下载免费PDF全文

叶鸿  杨涛  朱国荣  蒋少涌 《高校地质学报》2018,24(5):734

天然气水合物是重要的海洋油气资源,近年来利用孔隙水地球化学手段结合流体反应运移模型对水合物进行勘探已 成为研究热点。文章针对南海神狐海域钻探GMGS-1航次的数据资料,用孔隙水溴碘摩尔数比值拟合全新世流体运移速率, 构建了二期次非稳态水合物多相流体运移模型,并以SH7站位作为应用,发现自更新世以来研究区水合物成藏系统处于衰 退状态。通过模型参数敏感性分析,了解到影响模型输出的参数权重从高到低依次是沉积物孔隙度、有机质含量和沉积埋 藏速率。进一步数值分析表明,在水合物成藏系统中,有机质含量与水合物饱和度满足线性相关,其他主要参数与饱和度 的关系并非单调函数,且主导水合物稳定区内的甲烷物源是深部外源流体所携带的甲烷。多相流体运移模型对水合物资源 勘查具有一定的理论意义。  相似文献   

一种裂缝流体因子的提出及应用          下载免费PDF全文

孙炜  何治亮  李玉凤  张丰麒  周雁 《地球物理学报》2015,58(7):2536-2545

为了解决各向异性下的流体识别问题,将纵波各向异性裂缝预测以及Russell的流体因子融合到直角坐标系中,提出了一种能够同时检测裂缝发育情况以及流体性质的新的裂缝流体因子(Factor of Fluid-filled Fracture,FFF),并通过一组岩性参数检验了裂缝流体因子在裂缝预测及流体识别中的有效性.在理论研究的基础上,选取松辽盆地某地区的火成岩裂缝及流体识别研究为应用实例.通过与测井流体及裂缝信息的对比验证,裂缝流体因子能够较为准确地预测研究区裂缝和流体的分布情况,且裂缝流体因子在单井上的计算结果与单井含气饱和度吻合度较高.此外,根据实际应用效果,指出裂缝流体因子在应用中的局限性:裂缝流体因子在平面成图时受地层厚度影响较大,且无法预测裂缝方向.  相似文献   

Comparison of P‐wave attenuation models of wave‐induced flow          下载免费PDF全文

Weitao Sun  Tobias M. Müller  José M. Carcione  Hong Cao 《Geophysical Prospecting》2015,63(2):378-390

Wave‐induced oscillatory fluid flow in the vicinity of inclusions embedded in porous rocks is one of the main causes for P‐wave dispersion and attenuation at seismic frequencies. Hence, the P‐wave velocity depends on wave frequency, porosity, saturation, and other rock parameters. Several analytical models quantify this wave‐induced flow attenuation and result in characteristic velocity–saturation relations. Here, we compare some of these models by analyzing their low‐ and high‐frequency asymptotic behaviours and by applying them to measured velocity–saturation relations. Specifically, the Biot–Rayleigh model considering spherical inclusions embedded in an isotropic rock matrix is compared with White's and Johnson's models of patchy saturation. The modeling of laboratory data for tight sandstone and limestone indicates that, by selecting appropriate inclusion size, the Biot‐Rayleigh predictions are close to the measured values, particularly for intermediate and high water saturations.  相似文献   

基于Gassmann方程的流体替换方法在珊溪水库地震研究中的应用          下载免费PDF全文

钟羽云  张帆  阚宝祥 《地震工程学报》2015,37(3):678-686

引入基于Gassmann方程的流体替换方法,在分析地震波P波速度、波速比与岩石孔隙度和饱和度关系的基础上,应用于珊溪水库地震波速比和P波速度变化特征研究,得到:(1)珊溪水库震中区岩石始终处于接近水饱和的饱水状态,波速比和P波速度"下降-回升"的变化实质上反映了震中区岩石"孔隙度增大(饱和度减小)-饱和度增大"的变化,每一丛地震的波速比由极小值逐渐增大为极大值是由于岩石从不饱和状态变化到饱和状态;(2)根据每一丛地震波速比的变化,计算得到珊溪水库流体扩散率αs=1.06×104 cm2 s-1,该数值与美国南卡罗莱纳水库、巴西Acu水库、广东新丰江水库的流体扩散率基本一致;(3)震源区岩石孔隙度上限值为8.7%~2.0%,该数值与华东勘测设计研究院通过室内岩石物理力学性质试验测定的珊溪水库坝址区新鲜流纹斑岩的孔隙度平均值一致。  相似文献   

高面板坝地震动三维非一致输入的波函数组合法          下载免费PDF全文

姚虞  刘天云  张建民 《地震工程学报》2015,37(2):324-328,348

提出三维问题的波函数组合法求解不规则河谷的散射问题,应用到高面板坝动力有限元计算的地震动输入中,可以满足非一致输入的要求,并回避人工边界对外行波的反射问题。重点介绍三维问题的波函数组合法的理论推导和程序的算例验证,并给出将该方法应用到高面板坝地震动输入的基本步骤。  相似文献   

A comparison of wetness indices for the prediction of observed connected saturated areas under contrasting conditions   总被引：1，自引：0，他引：1       下载免费PDF全文

Geneviève Ali  Christian Birkel  Doerthe Tetzlaff  Chris Soulsby  Jeffrey J. McDonnell  Paolo Tarolli 《地球表面变化过程与地形》2014,39(3):399-413

For lack of other widely available spatial information, topography is often used to predict water fluxes and water quality in mesoscale watersheds. Such data have however proven to be misleading in many environments where large and flat valley bottoms and/or highly conducive soil covers determine water storage and water transport mechanisms. Also, the focus is generally on the prediction of saturation areas regardless of whether they are connected to the catchment hydrographic network or rather present in isolated topographic depressions. Here soil information was coupled with terrain data towards the targeted prediction of connected saturated areas. The focus was on the 30 km² Girnock catchment (Cairngorm Mountains, northeast Scotland) and its 3 km² sub‐catchment, Bruntland Burn in which seven field surveys were done to capture actual maps of connected saturated areas in both dry and humid conditions. The 1 km² resolution UK Hydrology of Soil Types (HOST) classification was used to extract relevant, spatially variable, soil parameters. Results show that connected saturated areas were fairly well predicted by wetness indices but only in wet conditions when they covered more than 30% of the whole catchment area. Geomorphic indices including information on terrain shape, steepness, aspect, soil texture and soil depth showed potential but generally performed poorly. Indices based on soil and topographic data did not have more predictive power than those based on topographic information only: this was attributed to the coarse resolution of the HOST classification. Nevertheless, analyses provided interesting insights into the scale‐dependent water storage and transport mechanisms in both study catchments. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Structure of residual oil as a function of wettability using pore-network modelling     

《Advances in water resources》2014

In the water flooding of mixed-wet porous media, oil may drain down to relatively low residual oil saturations (S_or). Various studies have indicated that such low saturations can only be reached when oil layers in pore corners are included in the pore-scale modelling. These processes within a macroscopic porous medium can be modelled at the pore-scale by incorporating the fundamental physics of capillary dominated displacement within idealised pore network models. Recently, the authors have developed thermodynamic criteria for oil layer existence in pores with non-uniform wettability which takes as input geometrically and topologically representative networks, to calculate realistic S_or values for mixed-wet and oil-wet sandstones [16, 21]. This previous work is developed in this paper to include (i) the visualisation of the 3D structure of this residual oil, and (ii) a statistical analysis of this “residual/remaining” oil. Both the visualisation and the statistical analysis are done under a wide range of wettability conditions, which is reported for the first time in this paper.The structure of residual oil for strongly water wet systems is well known (where residual = remaining oil) and our model agrees with this but this structure changes radically for mixed wet systems (where residual ≠ remaining) and this has not yet been visualised experimentally. We find that for more water-wet systems high final residual oil saturations are reached at relatively small amounts of water injected and this oil is present in the pores as bulk oil. On the other hand, for more oil-wet systems we find a slow decrease of the amount of remaining oil with increasing amounts of injected water. During the process, the remaining connectivity of the oil phase is increasingly provided by oil layers only, hence the slow drainage. The final residual oil saturation, only reached in the theoretical limit of an infinite amount of injected water, is almost entirely contained in large number of (relatively low volume) oil layers, which are present in pores of most radius sizes.  相似文献