【摘要】 在钻井数量相对少的情况下,充分挖掘利用地震信息来为海洋油气勘探开发服务则至关重要。叠前随机反演技术是一种将叠前AVA同步反演与随机模拟理论有机结合的反演方法,不但考虑了地下地质的随机特性,而且充分利用了叠前地震资料中与储层变化特征有关的地质信息,产生多种弹性参数体的多个等概率的预测结果。该结果既符合输入数据的地质统计学特征,且又受地质模型的约束,真正融合了测井数据的垂向分辨率高和地震数据横向分辨率高的优势。基于对南海L气田的地质认识,综合地质、测井和2个限角度叠加地震数据体,通过叠前随机反演技术得到了高分辨率的纵波波阻抗、纵横波速度比、密度以及泊松比、拉梅常数等一系列岩石弹性参数,同时,还直接得到储层岩性(砂、泥岩等)、物性(孔隙度、含水饱和度等)数据体,直观地展示出储层的空间分布,薄层砂体和砂泥互层都十分清楚,为该区沉积微相和储层非均质性的研究以及开发风险评价奠定了基础。更多还原

【Abstract】 It is critical to make full use of seismic data in offshore petroleum exploration when well data are relatively scarce.Stochastic pre-stack seismic inversion is a kind of technique that integrates pre-stack AVA synchronous inversion with stochastic modeling.It can not only reflect the stochastic features of subsurface geologic parameters,but make full use of the geologic information associated with reservoir heterogeneity in pre-stack seismic data.Several prediction results with equal probability can be obtained for various elastic parameters.These results accord with the geostatistical features of the inputs as well as being under the constraint of geologic models,thus realizing true integration of the high vertical resolution of logging data with the high lateral resolution of seismic data.Based on the geologic knowledge in the L Gas Field in South China Sea,geologic,logging and two stacked seismic data volumes are integrated to generate a series of rock elastic parameters through stochastic pre-stack inversion,including high resolution P-wave impedance,Vp/Vs ratio,density,poison ratio,and Lame constant.In addition,other data volumes of reservoir lithologies(sandstone,mudstone,etc.) and reservoir physical qualities(porosity,water saturation,etc.) are also directly obtained.The spatial distribution of reservoirs is directly displayed.The thin sandbodies and interbedded sandstones and mudstones are clearly mapped.All those above lay a robust foundation for the prediction of sedimentary microfacies and reservoir heterogeneity as well as for the appraisal of development risk.更多还原