虚拟井约束地震反演方法在台地斜坡带鲕滩储层预测中的应用——以四川盆地龙岗地区某单元为例

Application of Virtual-well Constrained Seismic Inversion in Prediction of Oolitic Shoal Reservoirs in Platform Slope Zone:A Case of Application in Longgang Area,Sichuan Basin

目前的地震反演均是基于已钻井的地质信息,对无井或少井地区的地震储层预测仍然比较困难。采用叠前和叠后混合反演的办法,实现虚拟井约束地震反演,能弥补缺少钻井的缺陷。该方法充分利用了叠前反演分辨率高和叠后反演效率高、抗噪能力强的优点,运用遗传算法原理,在优选控制点处进行精细的叠前地震波形反演以构建虚拟井,然后以虚拟井作为约束信息进行叠后反演,能够达到储层预测的目的。对四川盆地龙岗地区无井台缘斜坡带鲕滩储层进行了应用尝试,预测效果较好。虚拟井约束地震反演方法对油气勘探初期少井或无井研究区的储层预测是行之有效的技术方法之一。

The seismic inversion in present is all based on the geology information from drilled wells but the seismic prediction of reservoirs is still difficult in those areas where no or less wells drilled.The use of the inversion of mixing pre-stack with post-stack to realize the inversion with virtual wells can solve the problem of less well information.This method takes full advantage of high resolution in pre-stack inversion with high efficiency and high anti-noise ability in post-stack inversion.By principle of genetic algorithm,the way that fine pre-stack full-wave inversion can be done at selected control points to construct virtual wells and then these virtual wells as restricting information are applied in post-stack impedance inversion can realize the reservoir prediction.By this way,the mixing seismic inversion is well practised to the oolitic reservoirs without wells in the slope belt in Longgang area,Sichuan Basin.It is proved that the technology of virtual-well constrained seismic inversion is effective to predict reservoirs in immature areas without drilled wells.