应用地震道的F-LOG分析技术研究裂缝-孔隙性气藏

A research on fractured-porous gas reservoir by F-LOG analysis of seismic traces,

根据不同岩石对地震波不同频率分量衰减的差异,作者提出一种新的地震道分析技术,称为拟频率测井,用F-LOG表示。在地震道频谱分析的基础上,提取一个表征高频分量衰减程度(较低频分量而言)的参数,叫高衰指数。为了消除不相干因素的影响,计算中采用比值表示,故所得高衰指数只表示相对大小。 F-LOG是由地震道上每个样点值的高衰指数组成,它的相对高值表示对应的地层是岩石相对柔软、疏松或含油气情况。因此,利用这种F-LOG曲线有可能对储层的变化作出预测。文中讨论了F-LOG的层位标定、对比和提高分辨率的具体方法。采用本方法对四川盆地的乐平统生物礁的裂缝-孔隙性气藏;阳新统灰岩的裂缝-溶洞性气藏及中三叠统白云岩的裂缝-针孔性气藏开展了试验,获得了良好的效果。

In terms of the attenuation difference which seismic waves of different frequencies cause in various rock formations, the author advanced a new seismic-trace analysis technique that is called pseudo frequency log (F-LOG), High attenuation index that indicates the attenuation degree of relative high-frequency seismic content is obtained by making frequency spectrum analysis of seismic traces. In order. to remove the influence of unrelated factors, ratio is used. Thus, the high attenuation index only means relative degree A F-LOG curve consists of high attenuation indexes of all sampling values of a seismic trace. Its relative high values indicate that the relevant fomation is relatively soft, loose, or hydrocarbon bearing.Hence, F-LOG curves may be used to predict reservoir variation. It is discussed how we improve resolution and make horizon correlation of F-LOG curves. This method was used to analyse fractured-porous reef gas reservoir in Leping series, fractured-caved limestone gas reservoir in Yangxin series, and fractured needle-like porous dolomite gas reservoir in middle-Triassic system in Sichuan basin. Good effect was received.