组合高精度速度建模技术在渤海工区潜山成像中的应用

Application of Combined High Precision Velocity Modeling Technique in Buried Hill and Complex Structure Imaging in a Working Area at Bohai Sea

速度分析是地震数据处理的最重要环节之一,准确的速度场为偏移成像提供了最基础的保障,高精度的速度模型是提高潜山成像质量的关键。基于叠前深度偏移方法的速度建模过程中要同时兼顾好项目运行周期、建模效率、建模精度等不同要求。因此针对不同构造区,采用合适的速度建模方法尤为重要。文章以渤海某工区为例,首先探讨了不同速度建模方法的优缺点,然后根据工区目的层状况选择优势互补的速度建模方法。即针对浅层以平层构造为主的目的层采用网格层析方法,针对中深层潜山构造采用非线性反演方法,针对潜山内幕及基底构造区采用速度扫描的立体层析方法。实际资料处理结果表明:组合高精度速度建模方法可以比较快速的得到高精度速度模型,速度反演结果与测井数据及地震剖面高度吻合,在大大缩短项目运行周期的同时,提高了潜山构造区成像精度,验证了组合高精度速度建模技术的可行性、实用性和有效性。

Velocity analysis is one of the most important steps in seismic data processing.Accurate velocity field provides the most basic guarantee for migration imaging.High-precision velocity model is the key to the imaging quality improvement in buried hill and complex structure areas.In the process of velocity modeling based on pre-stack depth migration method,different requirements such as project operation cycle,modeling efficiency and modeling accuracy should be taken into account at the same time.Therefore,it is very important to adopt appropriate velocity modeling method for different tectonic zones.Taking a working area in Bohai Sea as an example,this paper firstly discusses the advantages and disadvantages of different velocity modeling methods,and then selects the velocity modeling method with complementary advantages according to the target layer in the working area.Grid tomography method is used for the target layer with shallow flat layer structure,nonlinear inversion method is used for the middle and deep buried hill and complex structural area,and velocity scanning stereoscopic tomography method is used for the interior of buried hill and basement structural area.The actual data processing results show that the combination of high precision velocity modeling method can obtain high precision velocity model,more rapid velocity inversion result in accordance with the logging data and seismic profile height,while greatly shorten project cycle and improve the precision of buried hill and complex structure area imaging,thus verifying the feasibility of combined high precision velocity modeling technology,practical and effective.