共查询到16条相似文献，搜索用时 125 毫秒
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复杂孔隙储层往往同时发育孔缝洞等多种孔隙类型,这种孔隙结构的复杂性使得岩石的速度与孔隙度之间的相关性很差.经典的二维岩石物理模版只研究弹性参数与孔隙度和饱和度之间的定量关系,而不考虑孔隙结构的影响,用这样的模版来预测复杂孔隙储层的物性参数时带来很大偏差.本文首先证明多重孔隙岩石的干骨架弹性参数可以用一个等效孔隙纵横比的单重孔隙岩石物理模型来模拟;进而基于等效介质岩石物理理论和Gassmann方程,建立一个全新的三维岩石物理模版,用它来建立复杂孔隙岩石的弹性性质与孔隙扁度及孔隙度和饱和度之间的定量关系;在此基础上,预测复杂储层的孔隙扁度、孔隙度以及孔隙中所包含的流体饱和度.实际测井和地震反演数据试验表明,三维岩石物理模版可有效提高复杂孔隙储层参数的预测精度. 相似文献
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通过融合Gassmann方程和由微分等效介质理论建立的干岩石骨架模型--DEM解析模型,本文提出根据纵波(和横波)速度反演岩石等效孔隙纵横比进行储层孔隙结构评价和横波速度预测的方法.首先,利用Gassmann方程和DEM解析模型建立岩石的纵、横波速度与密度、孔隙度、饱和度和矿物组分等各参数之间的关系;其次,将岩石孔隙等效为具有单一纵横比的理想椭球孔,应用非线性全局寻优算法来寻找最佳的等效孔隙纵横比使得理论预测与实际测量的弹性模量之间的误差最小;最后,将反演得到的等效孔隙纵横比代入到Gassmann方程和DEM解析模型中构建横波速度.实验室和井孔测量数据应用表明,反演得到的等效孔隙纵横比可准确反映储层的孔隙结构,对于裂缝型储层如花岗岩,其孔隙纵横比通常小于0.025,而对于孔隙型储层如砂岩,其孔隙纵横比通常大于0.08.只利用纵波与同时利用纵、横波反演得到的孔隙纵横比结果几乎完全一致,而且由纵波构建的横波与实测横波吻合良好,说明本文提出的等效孔隙纵横比反演及其横波速度预测方法是有效的. 相似文献
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碳酸盐岩组成复杂,储集层空间类型多,储层参数的规律性较差,AVO响应特征弱,尤其是孔隙形状对弹性参数的影响不可忽略.针对碳酸盐岩储层的特点,基于自洽模型和微分等效模型构建了多孔隙结构条件下多相介质的碳酸盐岩岩石物理模型.按照各相介质体积含量由小到大的顺序,先利用自洽模型计算孔隙度为50%时的双相等效介质,再通过微分等效模型将孔隙度调整至实际孔隙度,计算实际孔隙条件下的双相介质等效体,重复迭代该过程,最终构建出与实际岩石等效的介质体,计算获得等效岩石的弹性模量参数.通过实验对比了自洽模型、微分等效模型与自洽-微分等效模型的岩石弹性模量与孔隙度、孔隙纵横比之间的适用性规律.最后基于四川龙岗飞仙关组实际测井资料,结合自洽-微分等效模型进行了目标地层的横波预测.结果显示该模型的横波预测效果相对Xu-Payne模型预测,两者预测曲线比较接近,但在形态上更接近实际横波.SCA-DEM模型在孔隙度和孔隙纵横比上具有更好的适应性,为碳酸盐岩孔洞型储层的岩石物理建模提供了一种新参考. 相似文献
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储层参数地震反演是通过地震观测数据定量评估储层物性及含油气性的重要途径.中国西部致密砂岩油气分布范围广泛,具有巨大的勘探开发潜力,但其孔隙结构复杂,储层参数的定量预测难度较大.本文提出了一种基于可变临界孔隙度模型的储层参数地震反演方法.为有效描述储层的复杂孔隙结构,本方法将临界孔隙度作为变量,使其具有随深度变化的特征,以表征复杂孔隙结构,进而提高致密砂岩储层岩石物理建模的精度.此外,为直接从观测地震数据反演储层参数,结合岩石物理模型和地震反射系数方程建立正演算子;基于贝叶斯框架构建反演问题,采用混合高斯模型构建储层参数先验约束,用以描述储层的岩性(相)差异特征;基于临界孔隙度、泥质含量与孔隙度的统计关系,结合快速模拟退火算法,在迭代优化中使临界孔隙度与储层参数交替更新,用以提高反演结果稳定性.选用中国西部四川盆地某工区实际资料,对本方法进行应用测试与验证,结果表明本方法对于含气储层具有良好的指示性,相比常规固定临界孔隙度方法,本方法可以有效提升反演结果准确性. 相似文献
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碳酸盐岩的物性参数在油气勘探和开发的过程中起着重要的作用,且碳酸盐岩为具有多重孔隙类型的岩石,复杂的孔隙类型使得孔隙度与弹性参数之间的关系非常离散。本文基于岩石物理模型,提出一种碳酸盐岩物性参数替换的方法,首先对碳酸盐岩储层进行岩石物理建模,对模型中的等效孔隙纵横比进行反演,在进行替换时,保持其他参数不变,只改变孔隙度、方解石含量、含水饱和度和孔隙形状的体积分数中的一项。再结合AVO理论,进行正演模拟,正演模拟揭示孔隙度与孔隙形状的变化对地震响应的影响更为强烈,远远大于方解石含量、含水饱和度变化的影响,方解石含量和含水饱和度的变化对于地震响应的影响较微弱。实际资料应用表明,文章提出的碳酸盐岩物性参数的替换方法可以有效地分析物性参数及孔隙形状变化的影响,表征岩石的物理性质并判断岩石的孔隙类型。 相似文献
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碳酸盐岩孔隙结构参数构建与储层参数反演(英文) 总被引：3，自引：0，他引：3
碳酸盐岩储层孔隙结构相对碎屑岩更复杂,常用的岩石物理模型不能较好的描述其孔隙结构的变化规律,且岩石孔隙结构的差异较大程度上会影响岩石的弹性性质。本文首先利用岩石薄片分析了碳酸盐岩的微观孔隙结构。然后基于Gassmann方程和Eshelby-Walsh椭球包体裂缝理论,在合理的假设前提下给出了一种新的岩石物理建模方法,并且从中提取了一个参数来表征孔隙结构的变化规律。最后,基于全波列测井数据,我们利用该方法计算了单井的孔隙度,并与用常规方法预测的结果进行了比较,同时进行了地震储层参数反演。研究结果表明,孔隙结构对岩石的弹性性质的影响较大,且新的建模方法预测的孔隙度误差仅为0.74%。因此,该方法可有效的减小孔隙结构对计算各岩石弹性参数的影响并提高孔隙度的预测精度。 相似文献
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相对于常规砂岩,致密砂岩在岩石物理性质、力学性质等方面具有明显差异,并呈现出很强的非均质性.岩石物理模型能将储层参数与地震特性信息联系起来,因此可以作为致密砂岩储层参数与地震特性信息转换的桥梁.常规的岩石物理模型通常只考虑单一因素(例如非均匀性,单一孔隙,单一尺度等),建立的岩石物理模板并不适用于致密砂岩.本文针对高饱和气、微裂隙发育、非均质性强的致密砂岩储层,利用Voigt-Reuss-Hill模型计算混合矿物的弹性模量,采用微分等效介质(DEM)模型描述含裂隙、孔隙岩石的骨架弹性模量,基于Biot-Rayleigh波动方程构建了岩石物理弹性模板,给出了致密砂岩储层弹性参数与物性的关系.基于测井数据和实验数据对岩石物理弹性模板进行校正,并将校正后的岩石物理弹性模板结合叠前地震资料应用于川西地区储层孔隙度与裂隙含量预测.结果显示,反演裂隙含量、孔隙度与储层试气报告、测井孔隙度基本吻合,表明该模板能够较合理地应用于致密砂岩储层孔隙度及裂隙含量解释中. 相似文献
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孔隙纵横比是描述多孔岩石微观孔隙结构特征的重要参数,目前用于获取岩石完整孔隙纵横比分布的经典模型为David-Zimmerman(D-Z)孔隙结构模型,该模型假设岩石由固体矿物基质、一组纵横比相等的硬孔隙以及多组纵横比不等的微裂隙构成,并认为固体矿物基质和硬孔隙均不受压力影响,在此基础上,利用超声纵横波速度的压力依赖性反演岩石硬孔隙和各组微裂隙的孔隙纵横比及孔隙度.该方法的关键点在于以累积裂隙密度为桥梁,借助等效介质理论建立了岩石弹性模量和孔隙纵横比之间的内在联系.但在D-Z模型中,多重孔隙岩石累积裂隙密度的计算直接由单重孔隙裂隙密度公式实现,这种近似导致该模型在许多情况下难以获得良好的反演精度.为了完善经典D-Z模型,本文提出了一种基于虚拟降压的孔隙纵横比分布反演策略,通过多个假想降压过程实现累积裂隙密度的准确计算,并将基于DEM和MT的经典D-Z模型推广到KT和SCA中,结合四种等效介质理论建立了一套完整的反演流程.采用一系列砂岩和碳酸盐岩样品,测试了反演流程在实际岩芯孔隙纵横比提取中的应用效果,研究结果表明:与D-Z模型相比,本文方法的模拟结果与实际数据吻合更好,并同时适用于砂岩和碳酸盐岩;此外,通过分析四种等效介质理论的模拟结果发现,本文方法并不十分依赖于等效介质理论的选择,这些理论获得的孔隙结构参数随压力的变化趋势基本一致,数值上仅存在略微差异,且这种差异随着压力的增大逐渐消失.本文方法是经典D-Z孔隙结构模型的重要补充,对岩石孔隙结构表征、流体饱和岩石速度预测以及孔间喷射流效应的模拟具有十分重要的意义. 相似文献
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碳酸盐岩复杂的孔隙结构如何影响其弹性性质一直是地球物理研究的难点问题,在此基础上如何半定量甚至是定量地对碳酸盐岩储层预测,特别是如何有效地获取孔隙结构参数相关的地震属性体一直是油气工业界追求的目标,本研究从数字岩心角度入手,联合测井以及地震数据尝试探究这一问题的解决方案.首先针对代表不同孔隙结构类型的有限数目的碳酸盐岩样品获得其对应的高精度数字岩心数据体,为了获得更加可靠的具有地球物理含义的弹性性质随孔隙度变化的统计规律,我们通过子网格的技术,在有限数目的碳酸盐岩数字岩心数据体上获得了大量的数字岩心子网格样本,对于每个子网格样本可以分别获得其对应的数字岩心图像孔隙度、表征孔隙软硬程度的孔隙结构参数(γ)、以及基于有限元法模拟的弹性性质,由此基于数字岩心的研究思路,我们最终获得了基于孔隙结构因子表征与分类下的弹性性质与孔隙度的定量化解释量版.与此同时,在地震尺度上通过叠前地震资料获取的纵横波及密度属性体后,基于如上获得的定量化解释量版,我们最终获得了针对碳酸盐岩储层的新的属性体——孔隙结构参数(γ)属性体,这使得在地震尺度上预测碳酸盐岩储层的孔隙结构类型成为可能,也使利用地震数据在孔隙结构参数表征与分类下的碳酸盐岩储层反演精度的提高成为可能. 相似文献
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A critical porosity model establishes the empirical relationship between a grain matrix and a dry rock by the concept of critical porosity. The model is simple and practical and widely used. But the critical porosity in the model is a fixed value that cannot relate to pore structure. The aim of this paper is to establish the theoretical relationship between critical porosity and pore structure by combining Kuster–Toksöz theory with the critical porosity model. Different from the traditional critical porosity model, critical porosity is not an empirical value but varied with pore shape and the ratio of bulk modulus versus shear modulus of the grain matrix. The substitution of the theoretical relationship into Kuster–Toksöz theory will generate the formulae for the bulk and shear moduli of multiple-porosity dry rocks, which is named the multiple-porosity variable critical porosity model. The new model has been used to predict elastic moduli for sandstone and carbonate rock. We compare the modelling results for P- and S-wave velocities and elastic moduli with the experimental data. The comparison shows that the new model can be used to describe the elastic properties for the rocks with multiple pore types. 相似文献
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《中国科学:地球科学(英文版)》2021,(6)
Carbonate reservoirs have complex pore structures, which not only significantly affect the elastic properties and seismic responses of the reservoirs but also affect the accuracy of the prediction of the physical parameters. The existing rockphysics inversion methods are mainly designed for clastic rocks, and the inversion objects are generally porosity and water saturation. The data used are primarily based on the elastic parameters, and the inversion methods are mainly linear approximations. To date, there has been a lack of a simultaneous pore structure and physical parameter inversion method for carbonate reservoirs. To solve these problems, a new Bayesian nonlinear simultaneous inversion method based on elastic impedance is proposed. This method integrates the differential effective medium model of multiple-porosity rocks, Gassmann equation,Amplitude Versus Offset(AVO) theory, Bayesian theory, and a nonlinear inversion algorithm to achieve the simultaneous quantitative prediction of the pore structure and physical parameters of complex porous reservoirs. The forward modeling indicates that the contribution of the pore structure, i.e., the pore aspect ratio, to the AVO response and elastic impedance is second only to that of porosity and is far greater than that of water saturation. The application to real data shows that the new inversion method for determining the pore structure and physical parameters directly from pre-stack data can accurately predict a reservoir's porosity and water saturation and can evaluate the pore structure of the effective reservoir. 相似文献
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This paper discusses and addresses two questions in carbonate reservoir characterization: how to characterize pore‐type distribution quantitatively from well observations and seismic data based on geologic understanding of the reservoir and what geological implications stand behind the pore‐type distribution in carbonate reservoirs. To answer these questions, three geophysical pore types (reference pores, stiff pores and cracks) are defined to represent the average elastic effective properties of complex pore structures. The variability of elastic properties in carbonates can be quantified using a rock physics scheme associated with different volume fractions of geophysical pore types. We also explore the likely geological processes in carbonates based on the proposed rock physics template. The pore‐type inversion result from well log data fits well with the pore geometry revealed by a FMI log and core information. Furthermore, the S‐wave prediction based on the pore‐type inversion result also shows better agreement than the Greensberg‐Castagna relationship, suggesting the potential of this rock physics scheme to characterize the porosity heterogeneity in carbonate reservoirs. We also apply an inversion technique to quantitatively map the geophysical pore‐type distribution from a 2D seismic data set in a carbonate reservoir offshore Brazil. The spatial distributions of the geophysical pore type contain clues about the geological history that overprinted these rocks. Therefore, we analyse how the likely geological processes redistribute pore space of the reservoir rock from the initial depositional porosity and in turn how they impact the reservoir quality. 相似文献
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Wyllie's time-average equation and subsequent refinements have been used for over 20 years to estimate the porosity of reservoir rocks from compressional (P)-wave velocity (or its reciprocal, transit time) recorded on a sonic log. This model, while simple, needs to be more convincingly explained in theory and improved in practice, particularly by making use of shear (S)-wave velocity. One of the most important, although often ignored, factors affecting elastic velocities in a rock is pore structure, which is also a controlling factor for transport properties of a rock. Now that S-wave information can be obtained from the sonic log, it may be used with P-waves to provide a better understanding of pore structure. A new acoustic velocities-to-porosity transform based on an elastic velocity model developed by Kuster and Toksöz is proposed. Employing an approximation to an equivalent pore aspect ratio spectrum, pore structure for reservoir rocks is taken into account, in addition to total pore volume. Equidimensional pores are approximated by spheres and rounded spheroids, while grain boundary pores and flat pores are approximated by low aspect ratio cracks. An equivalent pore aspect ratio spectrum is characterized by a power function which is determined by compressional-and shear-wave velocities, as well as by matrix and inclusion properties. As a result of this more sophisticated elastic model of porous rocks and a stricter theory of elastic wave propagation, the new method leads to a more satisfactory interpretation and fuller use of seismic and sonic log data. Calculations using the new transform on data for sedimentary rocks, obtained from published literature and laboratory measurements, are presented and compared at atmospheric pressure with those estimated from the time-average equation. Results demonstrate that, to compensate for additional complexity, the new method provides more detailed information on pore volume and pore structure of reservoir rocks. Examples are presented using a realistic self-consistent averaging scheme to consider interactions between pores, and the possibility of extending the method to complex lithologies and shaly rocks is discussed. 相似文献
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碳酸盐岩复杂的孔隙结构如何影响其弹性性质一直是地球物理研究的难点问题,在此基础上如何半定量甚至是定量地对碳酸盐岩储层预测,特别是如何有效地获取孔隙结构参数相关的地震属性体一直是油气工业界追求的目标.本研究从数字岩心角度入手,联合测井以及地震数据尝试探究这一问题的解决方案,包括如下几个方面:(1)代表性碳酸盐岩储层样品获取;(2)CT扫描数字岩心数据体获取;(3)数字岩心数据的图像处理;(4)数字岩心数据的静态弹性模拟;(5)数字岩心子数据体的孔隙结构因子提取;(6)孔隙结构因子表征与分类下的弹性性质与孔隙度的定量化量版建立;(7)数字岩心-井-地震联合的孔隙度属性提取;(8)孔隙结构因子的地震属性体获取.本研究分为两篇系列文章上篇与下篇,上篇主要阐述如上提出的(1)—(4)方面,重点在于针对碳酸盐岩二值化图像处理的流程建立与验证,以及数字岩心静态弹性模拟的理论方面,这两方面是基于数字岩心获得精确的碳酸盐岩弹性性质模拟结果的关键所在;下篇主要阐述利用数字岩心数据获得孔隙结构因子的思路、理论与流程,以及为碳酸盐岩储层预测为目标而获得孔隙结构因子的地震属性体的实际应用方面.由于两篇文章共享数字岩心数据,同时所涉及的研究思路与流程形成一个有机整体,因此写成两篇系列文章而非两篇独立文章.本文为两篇系列文章的第一篇:上篇. 相似文献