裂缝性各向异性模型的多波响应分析

发布时间：2018-06-12 12:04

本文选题：裂缝 + 建模　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：裂缝性油气藏是我国含油气盆地中一种非常重要的油气藏类型,其地震响应特征分析能够建立地震数据和储层参数之间的联系,目前所研究的相关问题主要集中在裂缝性孔隙等效介质模型的建立和波场数值模拟方法研究上。本文通过Biot-Gassmann理论和Schoenberg等效介质理论结合实际油田裂缝储层参数建立理论模型,构建地质参数和地球物理参数之间的联系。通过单界面的AVO分析,总结了煤岩裂缝储层,页岩裂缝储层和致密砂岩裂缝储层在不同含流体性、不同裂缝大小的AVO响应特征。接着采用2.5D波动方程高阶有限差分的方法进行数值模拟,主要针对裂缝性各向异性模型,针对不同尺度的裂缝和不同背景介质的裂缝进行数值模拟,总结裂缝引起的不同多波地震响应规律。通过模拟分析,本文主要得出以下几点结论:(1)各向异性参数受岩性,孔隙度和含油气饱和度的影响。(2)不同岩性的含裂缝介质在含流体饱和度出现变化的情况下,PP和PS波反射系数随入射角变化曲线特征存在差异,据此可以区分岩性;裂缝尺度和各向异性参数的变化,影响了PP波和PS波AVO曲线的特征。(3)采用2.5D正演模拟的方法可以模拟裂缝介质中波场传播时出现横波分裂的现象,以及纵横波波场随着裂缝发育角度和大小呈现不同的特征,裂缝角度会影响波场传播的方向;裂缝增大到一定程度才会出现横波分裂现象,多组裂缝发育会令横波分裂现象更加复杂。(4)不同裂缝大小、发育角度和背景介质的裂缝产生的地震记录各有不同,主要表现在同样条件下的三分量之间和不同条件假设下的相同分量间振幅、衰减、极性和接收时长等方面的差异。
[Abstract]:Fractured oil and gas reservoir is a very important type of oil and gas reservoir in oil and gas bearing basins in China. The analysis of its seismic response characteristics can establish the relationship between seismic data and reservoir parameters. At present, the related problems are mainly focused on the establishment of fracture pore equivalent medium model and the numerical simulation method of wave field. In this paper, the biot-Gassmann theory and Schoenberg equivalent medium theory combined with the actual oilfield fracture reservoir parameters are used to establish a theoretical model to establish the relationship between geological parameters and geophysical parameters. Through AVO analysis of single interface, the AVO response characteristics of coal rock fracture reservoir, shale fracture reservoir and tight sandstone fracture reservoir are summarized. Then the 2.5D wave equation high order finite difference method is used to simulate the fracture anisotropy model, the crack of different scale and the crack of different background medium. The different multiwave seismic response laws caused by fractures are summarized. Based on the simulation analysis, the following conclusions are drawn in this paper: the anisotropic parameters are affected by lithology. Effect of porosity and oil and gas saturation. (2) the reflection coefficients of PP and PS waves vary with incident angle under the condition of fluid saturation change in fractured media with different lithology, so lithology can be distinguished. The variation of fracture scale and anisotropic parameters affects the characteristics of AVO curves of PP and PS waves. Using 2.5D forward modeling method, the phenomenon of shear wave splitting in fractured media can be simulated when the wave field propagates. The longitudinal and shear wave fields show different characteristics with the development angle and size of fracture, the angle of fracture will affect the direction of wave field propagation, and the shear wave splitting will occur only when the fracture increases to a certain extent. The development of multiple groups of fractures will make the phenomenon of shear wave splitting more complicated. (4) different fractures have different sizes, and the seismic records of fractures in the development angle and background medium are different. The differences of amplitude, attenuation, polarity and receiving time between the three components under the same conditions and the same components under different conditions are shown.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13;P631.4

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