摘要
地下介质不仅具有各向异性性质,还存在一定程度的复杂地质构造。运用均匀节点网格射线追踪方法计算旅行时要求网格单元的划分非常小以达到较高的旅行时精度,这种做法会产生大量的网格单元从而降低计算效率。基于均匀节点网格算法,研究了非均匀节点网格TI介质反射波射线追踪方法,采用较大的网格单元,通过在网格单元的每条边增加次一级节点来提高旅行时计算的精度与效率。首先讨论了qP,qSV和qSH波的群速度计算方法,然后给出了非均匀节点网格TI介质反射波射线追踪算法,最后分别求取了3种不同对称轴倾角的TI介质起伏地层模型qP,qSV和qSH反射波的射线路径和旅行时。结果表明:1非均匀节点网格射线追踪算法能够适用于复杂TI介质模型;2相同模型中不同波模式具有不同的反射路径和旅行时;3相同波模式在不同对称轴倾角模型中也具有不同的反射路径和旅行时。
The actual stratum not only has anisotropic property, but also has complicated geological structure to some extent. The efficiency of uniform grid ray tracing method is poor because there are too many cells caused by the refining grid algo- rithm. The ray tracing algorithm based on the nonuniform node meshes can obtain much higher numerical resolution and com- putational efficiency even with less primary node number and some secondary node number. Firstly, the calculation of the group velocities for qP,qSV and qSH waves are discussed in this article. Then,the reflected wave ray tracing in TI media is realized by combining these group velocities with the ray tracing algorithm based on the nonuniform node meshes. Finally,three undulating-layered TI models with different symmetry axes are built, the raypaths and traveltime of the qP, qSV and qSH reflected waves are computed for these models respectively. The numerical simulation results suggest that： the ray tracing algorithm based on the nonuniform node meshes has applicability for such a complex TI mediathree wave-modes have different raypaths and traveltimes for the same mode the same wave-mode also has different raypaths and traveltime for the model with different symmetry axes.
出处
《石油物探》
EI
CSCD
北大核心
2016年第1期25-32,共8页
Geophysical Prospecting For Petroleum
基金
国家科技重大专项(2011ZX05024-001-02)
国家自然科学基金(41504095
41004048
41364004
41104074
41304097)
国家科技支撑计划(2011BAB04B03)
东华理工大学博士科研启动基金(DHBK2013212)
核技术应用教育部工程研究中心基金(HJSJYB2015-9)
中国地质大学(武汉)地球内部多尺度成像湖北省重点实验室基金(SMIL-2015-10)
江西省教育厅基金(GJJ14476)项目联合资助~~
