低渗透压力条件下砂岩渗透性质的CT试验     

曹广祝  仵彦卿  丁卫华 《煤田地质与勘探》2005,33(4):59-62

运用岩石高压三轴加载装置和渗透压加载装置,对砂岩进行固定应力变渗透水压力试验,同时借助SOMATOMPLUS螺旋CT扫描机进行实时观测。通过试验结果分析,推出了基于CT数的岩石空隙率公式,从CT尺度上分析了岩石空隙率、渗透速度、渗流速度、微孔隙直径、渗透率等随渗透水压力的变化规律。结果表明:岩石的渗透参数随渗透压力的增加而增大,渗透参数随渗透压力的变化呈对数关系,这是由于渗透水压力使岩石内部空隙发生变形,这一变形为弹性变形;而渗流速度与渗透水压力呈线性关系,符合宏观尺度渗流的达西定律。   相似文献   

基于贝叶斯框架的各向异性页岩储层岩石物理反演技术   总被引：1，自引：0，他引：1       下载免费PDF全文

刘财  符伟  郭智奇  刘喜武  刘宇巍 《地球物理学报》2018,61(6):2589-2600

页岩岩石物理建模旨在建立页岩矿物组分、微观结构、流体填充与岩石弹性参数的关系.对四川盆地龙马溪组页岩进行岩石物理建模研究,针对页岩黏土含量高、层间微裂缝发育等特点,利用Backus平均理论描述页岩黏土矿物弹性参数,利用Chapman理论计算与水平微裂缝有关的VTI各向异性,并利用Bond变换考虑地层倾角的影响.提出以黏土矿物纵、横波速度和孔隙纵横比为拟合参数进行岩石物理反演的方法,并引入贝叶斯框架减小反演的多解性.由已知的黏土矿物纵、横波速度和孔隙纵横比作为先验信息,并以测井纵、横波速度作为约束条件建立反演的目标函数,同时利用粒子群算法进行最优化搜索.计算结果表明,基于先验约束和粒子群算法的反演方法能够较准确地反演黏土矿物的弹性参数、孔隙形态参数以及裂缝密度等参数.计算得到的黏土纵、横波速度较高,并且在一定范围内变化,这可能与龙马溪组页岩的黏土矿物组分中具有较高弹性模量的伊利石含量较高有关,同时也与黏土定向排列等微观物性特征有关.反演得到的裂缝密度与纵波各向异性参数ε呈明显的正相关,而与横波各向异性参数γ相关性较小.另外,页岩各向异性参数与黏土垂向的纵横波速度有较强的相关性.  相似文献   

基于微纳米孔隙理论的页岩气储层岩石物理建模方法          下载免费PDF全文

印林杰  印兴耀  宗兆云  陈本池  陈祖庆 《地球物理学报》2020,63(4):1642-1653

页岩储层由于其复杂的构造和孔隙特征,目前一般的岩石物理模型无法对其进行精确描述.微纳米孔隙作为页岩气主要的储集空间,对页岩整体弹性参数有较大影响.干酪根作为页岩中重要的有机质矿物,在页岩中的赋存状态随成熟度不同而变化,同时干酪根也是纳米级孔隙的主要发育场所.目前常规的岩石物理建模方法没有体现微纳米孔隙的作用,同时较少考虑不同成熟度下干酪根对页岩储层弹性性质的影响.本文采用一种微纳米孔隙理论描述页岩微纳米孔隙特性,考虑微纳米孔隙和不同成熟度下干酪根的赋存状态,应用上述微纳米孔隙模型、各向异性SCA-DEM模型、各向异性Eshelby-Cheng模型和Brown-Korringa固体替换方程等建立一种新的页岩储层岩石物理模型.利用中国西南某工区页岩气井对该模型进行验证,模型预测的横波速度与测井速度拟合较好.结果表明不同干酪根成熟度的页岩岩石物理建模结果具有一定的差异,据此可大致区分该工区井的干酪根成熟度;最后对微纳米孔参数进行正演分析,结果反映了页岩的纵横波速度随微纳米孔隙参数的变化趋势.  相似文献   

Diagenesis and reservoir quality of sandstones with ancient “deep” incursion of meteoric freshwater——An example in the Nanpu Sag,Bohai Bay Basin,East China     

《Marine and Petroleum Geology》2017

An example of diagenesis and reservoir quality of buried sandstones with ancient incursion of meteoric freshwater is presented in this study. The interpretation is based on information including porosity and permeability, petrography, stable isotopic composition of authigenic minerals, homogenization temperatures (T_h) of aqueous fluid inclusions (AFIs), and pore water chemistry. These sandstones, closely beneath or far from the regional unconformity formed during the late Paleogene period, are located in the thick Shahejie Formation in the Gaoliu area of Nanpu Sag, Bohai Bay Basin, East China. Early-diagenetic calcite cements were leached to form intergranular secondary pores without precipitation of late-diagenetic calcite cements in most sandstones. Feldspars were leached to form abundant intragranular secondary pores, but with small amounts of concomitant secondary minerals including authigenic quartz and kaolinite. The mass imbalance between the amount of leached minerals and associated secondary minerals suggests that mineral leaching reactions occurred most likely in an open geochemical system, and diagenetic petrography textures suggest that advective flow dominated the transfer of solutes from leached feldspars and calcites. Low salinity and ion concentrations of present pore waters, and extensive water rock interactions suggest significant incursion of meteoric freshwater flux in the sandstones. Distances of the sandstones to the regional unconformity can reach up to 1800 m, while with significant uplift in the Gaoliu area, the burial depth of such sandstones (below sea level) can be less than 800–1000 m during the uplift and initial reburial stage. Significant uplift during the Oligocene period provided substantial hydraulic drive and widely developed faults served as favorable conduits for downward penetration of meteoric freshwater from the earth's surface (unconformity) to these sandstone beds. Extensive feldspar leaching has been occurring since the uplift period. Coupled high T_h (95∼115 °C) of AFI and low δ¹⁸O_(SMOW) values (+17∼+20‰) within the quartz overgrowths show that quartz cementation occurred in the presence of diagenetic modified meteoric freshwater with δ¹⁸O_(SMOW) values of −7∼−2‰, indicating that authigenic quartz only have been formed during the late reburial stage when meteoric fresh water penetration slowed down. Secondary pores in thin sections and tested porosity suggest that meteoric freshwater leaching of feldspars and calcite minerals generated approximately 7–10% enhanced secondary porosity in these sandstones. Meteoric freshwater leaching reactions cannot be ignored in similar sandstones that located deep beneath the unconformity, with great uplift moving these sandstones above or close to sea level and with faults connecting the earth's surface with the sandstone beds.  相似文献   

山东省曹县城区地热资源评价          下载免费PDF全文

朱昶  费若强  宋帅良  马腾  张立  李军 《山东国土资源》2013,29(7):40-45

通过地球物理勘探、水文地质调查、钻孔和抽水试验,结合区域水文、气象和地质等资料,对山东省曹县城区地热地质条件、热储赋存条件有了初步认识,结合CD1号探采结合地热孔,对孔隙、岩溶裂隙型含水热储层及许庄复合热储层地热资源量进行了计算,对地热水资源进行了开发利用评价。  相似文献   

惠民凹陷古近系碎屑岩次生孔隙纵向分布规律   总被引：2，自引：0，他引：2  

张莉  朱筱敏  钟大康  崔可平 《地球科学》2007,32(2):253-259

为了在油气勘探的过程中更加准确地预测有效储层的分布, 根据铸体薄片、扫描电镜、碳酸盐含量、镜质体反射率、粘土矿物以及储层物性等数据, 研究了惠民凹陷古近系砂岩次生孔隙的纵向分布规律.在小于1400m的深度, 砂岩的孔隙主要为压实和胶结之后的原生粒间孔隙; 在埋深超过1400m以后开始出现少量次生孔隙, 在1400~1500m深度范围形成原生孔隙与次生孔隙并存的混合孔隙带; 超过1500m, 大量的次生孔隙出现在1500~2300m和2700~4000m的2个深度段.所收集的砂岩孔隙度和渗透率数据在纵向上的变化关系也间接证实了这一点.次生孔隙主要为长石溶蚀成因, 碳酸盐胶结物溶蚀是次要的.在次生孔隙发育带内, 惠民凹陷烃源岩演化产生大量有机酸和泥岩中的粘土矿物迅速脱水是产生溶蚀作用形成次生孔隙的直接原因.   相似文献   

寒冻条件下花岗岩小块体的风化模拟实验及其分析   总被引：12，自引：0，他引：12  

朱立平 Whal.  WB 《冰川冻土》1997,19(4):312-320

５０ｍｍ×５０ｍｍ×５０ｍｍ的一些小花岗岩块体被单轴挤压使之表面出现裂隙，然后分别预处理成干燥、水饱和与硫酸钠溶液饱和的３组样品，使之经历不同温度变幅下的冻融过程。在冻融过程中，分别记录了样品表面、表面下１０ｍｍ及２５ｍｍ处的温度变化，同时在实验前后，对所有样品都进行了超声波传输速率测定和重量测定。实验结果表明，这些小的花岗岩块体表面与内部的温度变化没有明显差异，其温度变化随外界温度而变化，但在外界温度变幅整体低于０℃时，岩石温度逐渐趋于稳定。样品在实验前后的重量变化很小，但是仍能反映最大的变化发生在水饱和的一组样品中。所有样品在实验后的超声波传输速率都明显下降，特别是在垂直于微裂隙的方向，超声波传输速率下降大于平均下降幅度，表明冻融过程中岩石内部的孔隙可能增大而微裂隙具有明显的加剧作用。  相似文献   

桂中坳陷北部下石炭统页岩储层微观孔隙结构特征     

陶金雨  申宝剑  潘安阳 《地质论评》2021,67(Z1):67z1117-67z1118

正页岩储层的孔隙结构特征对页岩气的富集具有重要影响(Loucks et al., 2007;胡宗全等,2015)。我国广西桂中地区页岩气储集孔隙精细表征的研究尚处于空白状态(毛佩筱,2018),为了推进桂中地区上古生界的页岩气勘探工作,本次研究从岩石矿物成分、有机质含量及其演化、物性、储集空间等方面,对桂中地区鹿寨组页岩气储集孔隙进行精细表征,以期为今后的页岩气勘探开发提供参考。  相似文献   

Suspended sediment in rapid subsurface stormflow on a large field plot     

David H. Pilgrim  Dale D. Huff 《地球表面变化过程与地形》1983,8(5):451-463

The occurrence of rapid movement of suspended sediment in subsurface stormflow on a large field plot in California is described. Concentrations of over 1000mgl^?1 were recorded in storms of only low to moderate intensity. The observed sediment was composed of uniformly fine-sized particles 4 to 8 μm in diameter. The mode of transport seems different from processes previously reported. Differences in sediment concentrations in different events, levels of ¹³⁷Cs on the sediment, and several other types of evidence indicate that the sediment was detached and entrained at the ground surface by raindrop impact and that the water and sediment flow occurred mainly through macropores in the soil. As conditions similar to those at the study site are not uncommon, it seems probable that the phenomenon may occur in many regions.  相似文献   

油气藏微观不均一性及其意义   总被引：18，自引：3，他引：15  

潘长春  杨坚强 《沉积学报》1998,16(4):98-104

油气储集岩中不同孔隙类型（开放型与封闭型）中的油气组分、孔隙中自由状态的油气组分、矿物颗粒表面吸附（束缚状态）的油气组分、以及矿物内部油气包裹体之间常规生物标志化合物组成（甾、萜分布）存在明显的差异,反映了不同成藏阶段油气组成的地球化学特征,展示了油气充填过程,同时为油源对比提供了新方法。  相似文献