各向异性页岩岩石物理建模及储层脆性评价

发布时间：2018-03-15 16:47

本文选题：页岩储层　切入点：各向异性　出处：《中国石油大学(北京)》2016年博士论文　论文类型：学位论文

【摘要】：页岩储层是目前非常规地球物理勘探的研究热点之一。而地震岩石物理分析技术是储层物性参数描述的重要手段。作为地震弹性参数与储层物性参数之间的“桥梁”,地震岩石物理分析大体可分为“正问题”和“反问题”。正问题主要涉及岩石物理模型的构建及地震属性模拟,而反问题主要包括储层参数反演。本文从正问题出发,构建了适合页岩储层的各向异性模型。并针对反问题引入网格分析法优化了反演算法。最终利用反演结果讨论了页岩储层的各向异性特征。同时,分析了页岩储层的热点属性:脆性,优选脆性表征公式,结合井震资料,实现对页岩储层的脆性分析。本文的主要成果可以归纳如下:(1)论文构建针对页岩储层的各向异性岩石物理模型。模型着重模拟了页岩储层由(1)有机质的富集;(2)黏土的定向排列和(3)扁平状的孔隙形态所引起的各向异性。模型利用SCA+DEM模拟了页岩中的有机质,并引入成层因子(CL)模拟黏土的成层性强弱,最后利用孔隙纵横比控制了页岩的孔隙形态。实现了对页岩不同各向异性成因的精细模拟。(2)随后,基于构建的页岩模型,在常规二维孔隙纵横比反演模板的基础上,引入矿物含量作为第三维参数,建立了更符合真实情况的三维孔隙纵横比反演模板,对储层的孔隙形态和孔隙类型进行反演,并利用反演得到的孔隙参数,实现对页岩储层的纵横波速度预测。(3)为了获取更多的储层物性信息,本文构建双扫描反演流程,反演得到表征孔隙形态和黏土成层性强弱的模型参数孔隙纵横比(α)和成层因子(CL)。实现对储层各向异性参数的预测,并讨论了各向异性参数与储层物性参数的相互关系。(4)针对反问题,本文通过引入网格分析法,对储层参数的反演算法进行改进。网格分析法通过将实测测井值正态分布展开,将测井的误差考虑进反演算法中,最终得到待反演参数的概率密度分布图。降低了由测量值不准引起的预测误差,提高了预测结果的可信性。并预测了目的层的孔隙形态及孔隙类型概率密度分布。(5)优选现有脆性公式,发现基于弹性参数构建的脆性指数的预测精度总体高于基于矿物组分的脆性公式。基于杨氏模量泊松比构建的脆性指数对岩性的变化较敏感,而拉梅系数构建的脆性表征公式对孔隙流体更为敏感。基于模型,构建岩石物理脆性模板,优选脆性敏感参数。研究发现低泊松比,中高杨氏模量,往往对应高孔脆性页岩,是页岩开采的“甜点”区域。最终,针对西南四川盆地龙马溪组-五峰组的页岩储层进行脆性评价,叠前同时反演结果和测井脆性分析结果较为吻合,验证了脆性分析结果的稳定性和可靠性。
[Abstract]:Shale reservoir is one of the research hotspots in unconventional geophysical exploration at present. Seismic rock physical analysis is an important means to describe reservoir physical parameters, which is a bridge between seismic elastic parameters and reservoir physical parameters. Liang, seismic rock physics analysis can be divided into "positive problem" and "inverse problem". The positive problem mainly involves the construction of rock physical model and seismic attribute simulation. The inverse problem mainly includes inversion of reservoir parameters. The anisotropic model suitable for shale reservoir is constructed, and the inversion algorithm is optimized by introducing the grid analysis method to solve the inverse problem. Finally, the anisotropic characteristics of shale reservoir are discussed by using the inversion results. At the same time, The hot spot attributes of shale reservoir are analyzed, such as brittleness, optimum selection of brittleness representation formula, combined with well shock data, The main results of this paper can be summarized as follows: 1) the physical model of anisotropic rock for shale reservoir is constructed. The model focuses on simulating the accumulation of organic matter in shale reservoir. The anisotropy caused by the directional arrangement of soil and the flat pore morphology of the soil. The model uses SCA DEM to simulate the organic matter in shale. The stratification factor CLA is introduced to simulate the stratification of clay. Finally, the pore morphology of shale is controlled by the aspect ratio of porosity, and the fine simulation of different anisotropic origin of shale is realized. Then, based on the shale model, the shale model is constructed. On the basis of the conventional two-dimensional inversion template of pore aspect ratio, mineral content is introduced as the third dimension parameter, and a three-dimensional pore aspect ratio inversion template is established, which is more suitable for the real situation. The pore morphology and pore type of the reservoir are inversed. In order to obtain more information of reservoir physical properties, a double scan inversion process is constructed to predict the compressional and shear wave velocity of shale reservoir by using the pore parameters obtained by inversion. The model parameters, porosity aspect ratio (伪) and stratification factor CLA, are obtained to characterize pore morphology and clay stratification. The prediction of reservoir anisotropy parameters is realized. The relationship between anisotropic parameters and reservoir physical parameters is discussed. Aiming at the inverse problem, the inversion algorithm of reservoir parameters is improved by introducing the grid analysis method, which expands the normal distribution of the measured logging values. The error of logging is taken into account in the inversion algorithm, and the probability density distribution map of the parameters to be retrieved is obtained, which reduces the prediction error caused by the uncertainty of the measured values. The reliability of the prediction results is improved, and the probability density distribution of pore morphology and pore type of the target layer is predicted. It is found that the prediction accuracy of brittleness index based on elastic parameters is higher than that of brittleness formula based on mineral components, and the brittleness index based on Young's modulus Poisson's ratio is more sensitive to the change of lithology. On the other hand, the brittleness characterization formula constructed by Lamy coefficient is more sensitive to pore fluid. Based on the model, rock physical brittleness template is constructed and the sensitive parameters of brittleness are optimized. It is found that low Poisson ratio and medium and high Young's modulus often correspond to high porosity brittle shale. Finally, the brittleness evaluation of shale reservoir of Longmaxi formation and Wufeng formation in southwest Sichuan basin is carried out, and the results of simultaneous inversion before stack are in good agreement with the results of log brittleness analysis. The stability and reliability of the brittleness analysis results are verified.
【学位授予单位】：中国石油大学(北京)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P618.13

【相似文献】