煤层裂隙地震预测方法研究

发布时间：2018-05-19 10:46

本文选题：煤层裂隙 + 相干　；参考：《成都理工大学》2017年硕士论文

【摘要】：煤层气一般赋存于煤系地层的裂隙(裂缝)中,而这些裂隙与地下构造分布特征有着密切关联。随着煤层气勘探开发的深入发展,对识别和描述地下煤系地层内部的裂隙的要求越来越精细。在地震数据体中,包含有很多与煤系地层内部和其构造分布密切相关的信息,精准地提取这些信息能有助于识别煤系地层的裂隙。本文将延川南2#煤层作为本次的研究对象,综合预测研究区的煤层裂隙分布特征及裂隙发育区,主要取得以下研究成果:(1)针对工区地质特征,建立了多种地质模型,进行数值模拟,得到了各模型的地震响应特征,分析地震响应特征与煤层孔隙度之间的关系。分析了振幅、复地震道和频谱类属性这三种动力学参数属性对煤层孔隙度的敏感性。(2)利用PCA对2#煤层的振幅、复地震道和频谱类属性这三种动力学参数属性进行多属性融合,融合后最大特征值对应的主成分分量包含原有地震属性的大部分特征,得到研究区的融合属性层位切片。(3)以曲率属性提取了地震数据体中有关2#煤层的地下构造的空间方位信息,反映地下构造的形变,识别细微的构造特征。在煤层原有的割理基础上,断层、挠曲等构造变形会产生更多的裂隙,所以曲率属性能从构造变形方面来反映了煤层内部裂隙发育情况。(4)相干属性能检测地层内部横向的变化,但一般煤层内部横向的变化不足以对地震波形造成明显的变化,所以相干属性对煤层内部裂隙没有很好的识别效果。针对相干属性的不足,结合广义S变换的谱分解和相干技术,提高对煤层横向细微变化的识别能力。结合曲率和基于广义S变换的分频相干属性,预测煤系地层的孔隙、裂隙和断裂破碎带的分布特征,提高识别煤系储层预测裂隙发育程度的准确性。煤层裂隙与煤层气富集区具有一定对应关系,因此煤层裂隙预测为煤层气的勘探开发提供了一条有效途径。
[Abstract]:Coal-bed methane (CBM) generally occurs in fractures (fractures) in coal-bearing strata, which are closely related to the distribution of underground structures. With the development of coalbed methane exploration and development, the requirements of identifying and describing the fractures in underground coal measures are becoming more and more precise. In the seismic data body, there are a lot of information closely related to the coal measure strata and their structural distribution. Accurate extraction of these information can help to identify the fractures in the coal measure strata. In this paper, the coal seam of Yanchuan Nan2# is taken as the object of this study. The distribution characteristics of coal seam fractures and fracture development areas in the study area are comprehensively forecasted, and the following research results are obtained: (1) aiming at the geological characteristics of the work area, a variety of geological models are established. Through numerical simulation, the seismic response characteristics of each model are obtained, and the relationship between seismic response characteristics and coal seam porosity is analyzed. In this paper, the sensitivity of amplitude, complex seismic trace and spectrum attributes to coal seam porosity is analyzed. PCA is used to fuse the amplitude, complex seismic trace and spectrum attributes of coal seam. The principal component components corresponding to the fused maximum eigenvalues contain most of the features of the original seismic attributes. By using curvature attribute, the spatial orientation information about the underground structure of coal seam in 2# is extracted from the seismic data body, which reflects the deformation of the underground structure and recognizes the subtle structural characteristics. On the basis of the original cleats of coal seams, structural deformation such as faults and flexures will produce more cracks, so the curvature attribute can reflect the development of fractures in the coal seam from the aspect of structural deformation.) coherence attributes can detect lateral changes in strata. But the lateral change of coal seam is not enough to cause obvious change of seismic waveform, so the coherent attribute has no good recognition effect on the internal fracture of coal seam. In view of the deficiency of coherent attribute, combined with spectral decomposition and coherence technology of generalized S-transform, the ability to recognize the lateral subtle changes of coal seam is improved. Combined with curvature and frequency-division coherent attribute based on generalized S-transform, the distribution characteristics of pore, fracture and fracture zone of coal measure strata are predicted, and the accuracy of predicting fracture development degree of coal measure reservoir is improved. The coal seam fissure has a certain corresponding relationship with the coalbed methane accumulation area, so the prediction of coal seam fissure provides an effective way for the exploration and development of coalbed methane.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13;P631.4

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