地震属性在煤层气储层预测中的应用

Application of Seismic Attribute Analysis Technology in Coal Gas Reservoir Forecasting

煤层具有高声波时差、低密度、低波阻抗、低伽马、高电阻率的测井响应特征,因而煤层具有较为明显的地震响应特征。应用地震数值模拟方法模拟煤层与顶、底板岩层之间较强的地震反射界面,随着煤层厚度的变化,煤层与顶、底板岩层间形成的地震反射强度会随之改变;另外,随着同一套煤层层数的增多,煤层与顶、底板岩层间的地震反射强度也会增大。根据煤层的特征,分别从构造、煤质、煤层上覆地层厚度、煤层的直接盖层、物性等方面对相关的地震属性分析方法进行优选,优选出地震振幅、地震旅行时、曲率、频率、吸收衰减、波阻抗反演等地震方法适应于煤层气储层预测研究,并将这些方法应用于实际地震资料,取得较好的预测结果。

Seismic attribute analysis technology is efficiently in coalbed methane reservoir forecasting. Coal bed own the logging feature of high acoustic travel time, low density, low impedance, low gamma,high resistivity. So the seismic response of coal bed is obvious. Based on the analysis of seismic numerical modeling, there is strong reflection interface between coal bed and upon or down rock layer, which is obvious in seismic response feature, and the reflection will become strong or weak as the thickness of coal bed,the reflection will become strong with the number of coal layer changes more. Upon the feature of coal bed, we choose the seismic attribute from structure, medium, the thickness of rock layer above coal bed, direct covering rock, physical property, and get seismic amplitude, travel time of seismic, curvature, frequency, absorption, impedance are applicable in coal gas reservoir forecasting. These technology are used in actual seismic data and get a good use in forecasting coal gas.