摘要:
当煤层顶底板为泥岩时,其煤层气含量一般较高. 为预测煤层气富集区,通过地震资料和测井数据分析,基于纵波阻抗反演和拟声波阻抗反演技术的方法获得煤层顶底板位置和砂泥岩的分布规律,为煤层气勘探开发提供依据. 首先由于煤层纵波阻抗值很低,可在纵波阻抗反演剖面中准确获得煤层顶底板位置;其次利用自然伽马曲线构建拟声波曲线,在横向连续性强的拟声波阻抗反演剖面中,由于泥岩表现为拟声波阻抗高值,砂岩表现为低值,可通过数据分析得到砂泥岩值域范围;最后可以此为依据进行精细划分. 实际应用表明,这种方法比传统纵波阻抗反演方法效果更好,分辨率更高.
Abstract:
The coalbed methane content is often relatively high where the immediate roof and floor of the coal seam are mudstone. In or-der to predict the coalbed methane rich region, position of coal seam roof and floor and distribution of sandstone and mudstone are based on acoustic wave impedance inversion and pseudo-acoustic inversion technique through seismic data and well logging data analy-sis. This method provides a basis for the exploration and development of coalbed methane. First of all, the position of coal seam roof and floor can be acquired accurately in the acoustic wave impedance inversion profile due to low acoustic impedance values of coal. Pseudo-acoustic curve is constructed by natural gamma curve. In the pseudo-acoustic inversion profile which has high lateral continuity, the mudstone shows high values, the sandstone shows low values, so it is possible to characterize the sandstone and the mudstone when the range is acquired though data analysis. The application in practice shows that, the inversion method is better than conventional one in resolution and achieved good results in practice.
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