基于叠前反演的储层预测技术在陕北黄土塬白云岩气藏的应用

摘要

In recent years, a large number of dolomite lithologic gas reservoirs have been found in the middle part of Ordovician strata in the Shanbei loess tableland. Nevertheless, the surface conditions of this area are complex, which leads to a poor seismic data imaging accuracy, and the main reservoir Mawu5 Formation of Ordovician is characterized by extensive distribution,thin reservoir,strong hetero⁃geneity and drastic lateral variation in physical properties, which results in more difficulties in seismic prediction. With the 3D high⁃fi⁃delity seismic data of 600 km2 collected in the Shanbei loess tableland in recent years, technologies of FFP analysis and function formu⁃la between the elastic parameters fitted by drilled wells were applied innovatively based on an analysis of rock physical sensitive factors and the strengthening of pre⁃stack inversion. The dolomite probability, gas probability, porosity and gas saturation of Ma55 Formation in the project was calculated. The favorable gas area in the dolomite reservoir of Ma55 in the Su203 well district was described clearly, and then the favorable drilling targets were evaluated and obtained, thus achieving good results.%近年来，陕北黄土塬地区下古生界奥陶系中组合马五5地层发现了一大批白云岩岩性气藏。但是由于黄土塬地表条件复杂，地震资料成像精度差，马五5储层分布面积广、厚度薄、非均质性强、横向变化快，地震预测难度非常大。文中针对近年在陕北苏203井区实施的600 km2三维高保真地震资料，在强化岩石物理分析和叠前反演的基础上，创新应用FFP （岩相流体概率）分析技术，结合完钻井拟合弹性参数函数关系式，计算得到工区马五5地层的白云岩概率体、含气概率体、孔隙度及含气饱和度，刻画了苏203井区马五5白云岩储层含气有利区的平面展布。评价、落实了钻探有利目标，取得了较好的效果。