波阻抗反演在吉林探区煤层特征分析及储层预测中的应用

The application of impedance inversion for characteristics analysis and reservoir prediction in Jilin coalfield

地震勘探已经从认识地下构造形态的构造勘探,逐渐发展成直接应用地震信息判断岩性、分析岩相、定量计算岩层物性参数等的岩性勘探,地震反演技术是这一发展过程的产物.利用地震方法解决煤田勘探问题一直以来是一个研究的热门课题.由于煤层的构造特征常常较差,常规的构造地震勘探方法一般很难获得良好的储层特征,而波阻抗是反映储集岩的一种重要物性参数,与振幅等反映界面性质的参数相比,波阻抗具有更低的多解性和更高的储层横向预测精度,因此在煤田勘探中得到广泛应用.本文主要回顾了波阻抗反演方法的基本原理及特点,并以吉林某煤层采区岩性勘探为例,说明波阻抗反演结果在该探区煤层中的响应特征及储层分析结果.实际数据处理的结果表明,在波阻抗反演时间剖面上,该地区各地层单元之间和地层单元内部岩层之间的接触关系特征更加明显,特别是地层的不整合接触关系表现得尤为突出,能够提供较普通地震时间剖面更好的煤层识别特征和更加可靠的储层预测依据.

Recently, research topics in seismic exploration are moving lowards to analyzing lithology, lithofacies, and quantitative properties of matter from structure exploration. Inversion technique provides an approach to solve the problem. Using seismic exploration technique to solve lithological problems in coal fields is a hol topic in which people have been studying for recent years. In general, the structural characteristics of coal reservoir is always weak, so classic structural exploration methods cannot get a good reservoir characteristics. Impedance inversion is an important property of matter parameter. Compared with the other seismic stratum parameters eg., amplitude, impedance inversion technique has both lower interpretation ambiguity and higher accuracy of reservoir prediction. So this technique is widely used in coal exploration. In this paper, the principle and characteristics of impedance inversion are introduced. It is also applied for lithological exploration in Jilin coal seam area. The example illuslrates the detailed application and results about impedance inversion of coal seam lithological exploration. The that the stratigraphic units and internal rocks in the research area display more obvious impedance inversion profile, especially the relationship of unconformable contact, which recognition feature than standard seismic time profile. At the same time, impedance inversion field data results show contact relationship in provides a better coal also gives more reliable reservoir prediction.