非线性层析技术在琼东南天然气水合物成像中的应用  

Application of non-linear tomography technology to gas hydrate imaging in the Qiongdongnan area

作　　者：帅庆伟 徐云霞[1,2] 文鹏飞 沙志彬[1,2] 万晓明 SHUAI Qingwei;XU Yunxia;WEN Pengfei;SHA Zhibin;WAN Xiaoming(Key Laboratory of Mineral Resources,Ministry of Natural Resources,Guangzhou 510075,China;Guangzhou Marine Geological Survey,China Geology Survey,Guangzhou 510760,China)

机构地区：[1]自然资源部海底矿产资源重点实验室,广州510075 [2]中国地质调查局广州海洋地质调查局,广州510760

出　　处：《海洋地质与第四纪地质》2020年第3期206-213,共8页Marine Geology & Quaternary Geology

基　　金：国家重点研发计划项目“中国海域冷泉系统演变过程及其机制”(2018YFC0310000);广东省促进经济高质量发展专项资金“海洋经济发展项目”(GDOE(2019)A39);中国地质调查局地质调查项目“神狐海域天然气水合物先导试验区资源评价”(DD20190224)。

摘　　要：琼东南海域地震剖面上存在大量的含气特征,同相轴下拉、明显的速度横向变化等,因此水合物之下地层存在成像模糊且归位不准等问题,本文利用基于非线性层析的深度偏移方法提升成像精度。该方法采用全三维体的层析成像反演法建立深度域速度模型,通过对深度偏移道集拾取RMO量,并对其进行反偏移计算运动学不变量;在建立层位、倾角等骨架信息约束的混合模型基础上,利用运动学不变量进行速度层析,使得RMO最小以实现模型更新。该方法避免了常规速度更新的多次迭代偏移,能极大地提升层析效率,并能充分利用剖面骨架和倾角信息,获得高精度的速度模型。在琼东南水合物资料的实际应用中,有效地消除了含气对地层的影响,获得高精度的深度域成像结果。There are a substantial amount of gas-bearing sediments occurred in the Qiongdongnan area.Geophysical features,such as in-phase axial pulling down and velocity changes are commonly observed.Therefore,the images of sediments below the gas hydrate layer are always blurring.In this paper,a method based on non-linear tomographic depth offset is adopted to enhance the accuracy and resolution of imaging.The method of full 3D tomography inversion is used to establish the velocity model in depth domain,and the kinematic invariants are calculated by picking up the RMO of depth offset gathers and reverse deflection.Based on the mixed model under the constraints of skeleton information,such as horizons and inclination angles,kinematic invariants are used for velocity tomography to minimize RMO for model updating.This method can avoid multiple iteration PSDM processing while updating velocity and greatly improve the tomographic efficiency.Then the high precision velocity model can be obtained by making full use of the profile skeleton and inclination information.The effect of gas on stratigraphic formation is effectively eliminated in the practical application of hydrate data in the Qiongdongnan area,and high precision depth imaging results are obtained.

关 键 词：非线性层析 混合模型 运动学不变量 深度偏移 

分 类 号：P738[天文地球—海洋地质]