【摘要】 时移地震技术是基于已知地震反射特征随储层参数的变化规律来实现油气藏动态监测的。为了准确得到这一变化规律,通过研究形成了一套完整的基于测井资料的储层模量反演与地震反射特征分析技术。首先从研究区实际测井资料出发,采用自适应模拟退火算法反演储层岩石基质模量并计算不同储层条件的弹性参数;然后精确求解Zoeppritz方程,得到地震波反射系数的解析解,同时对研究区典型地质模型进行波动方程数值模拟,得到地震波反射系数的数值解;通过对解析解和数值解中的AVO现象进行对比分析和校正,得到不同储层条件下地震反射特征的变化规律,总结建立适用于研究区的岩石物理量版,用于指导时移地震成果数据的分析解释。研究中还发现,地震反射特征对储层孔隙度的变化非常敏感,如果水力压裂、CO2注采及其它因素造成储层孔隙度的微小变化,以及地震解释工作中孔隙度的预测存在微小偏差,都会引起地震反射特征的变化,可能造成储层含油气变化的假象,给油气检测带来陷阱。更多还原

【Abstract】 Time lapse seismic is an effective technology for reservoir dynamic monitoring.It is based on the known variation rule of seismic reflection characteristics via reservoir parameters.In order to obtain this rule accurately,a series of techniques is established based on logging data for reservoir moduli inversion and seismic reflection chracteristics analysis.According to the rock physics theory,the reservoir rock matrix modulus is inversed by the adaptive simulated annealing algorithm and the elastic parameters under different reservoir conditions are calculated from the actual logging data.The analytic solution of seismic wave reflection coefficients can be obtained by solving the Zoeppritz equation exactly.Considering the difference between plane wave solution and point source wavefield,the numerical modeling of elastic wave equations to the typical geological model is performed.Then by some comparison,the analysis and correction to the AVO characteristics of the analytical and numerical solutions are carried out,and the reflection characteristics under different reservoir conditions could be obtained.Finally,the rock physics template suitable to target area is established to guide the interpretation of real data.It is also found that seismic reflection is very sensitive to the variation in reservoir porosity.If there are small changes of porosity caused by hydraulic fracturing,CO2 injection and other artificial factors,or there are some tiny errors of porosity prediction in seismic inversion and interpretation,a relatively great change might be occurred on the seismic reflection characteristics,which would lead to pitfalls in the prediction of reservoir parameters in oil-gas reservoir monitoring.更多还原