基于测井修正的TTI伪弹性波逆时偏移优化方法

Optimization of Pseudo Elastic Wave Reverse Time Migration with Logging Correction in TTI Media

曾庆才 王清华 曾同生 陈胜 张凯

ZENGQingcai WANGQinghua ZENGTongsheng CHENSheng ZHANGKai

中国石油勘探开发研究院油气地球物理研究所, 北京 海淀 100083 中国石油塔里木油田公司, 新疆 库尔勒 841000 中国石油大学(华东)地球科学与技术学院, 山东 青岛 266580

Institute of Oil and Gas Geophysics, PetroChina Research Institute of Petroleum Exploration & Developmen, Haidian, Beijing 100083, China Tarim Oilfield Company, PetroChina, Korla, Xinjiang 841000, China School of Geoscience, China University of Petroleum (East China), Qingdao, Shandong 266580, China

在各向异性介质中，地震波在不同传播方向上速度不同。利用各向同性波动方程不能准确描述地震波的传播，在成像时会导致深层同相轴位置不准确等问题。在TTI介质弹性波方程的基础上，一方面将横波速度设置为较小的数值并引入震源环消除伪横波假象，另一方面利用测井数据对偏移参数场进行约束与修正，以提高深层复杂构造的成像精度。逆时偏移方法在进行成像时，低频噪声会对成像产生影响。为此，以拉普拉斯滤波算子去噪为基础，通过提取角度域共成像点道集，采用分角度叠加成像压制由于参数不准确导致的强振幅低频噪声。实际数据在进行成像时计算量大，采用CPU与GPU协同运算对逆时偏移进行加速以提高计算效率。模型和实际资料处理结果表明，基于测井数据约束的TTI介质逆时偏移方法能够对深层复杂构造目标区域进行准确成像，证明了方法的可行性。

In anisotropic media, seismic waves have different velocities in different propagation directions. The use of isotropic wave equations cannot accurately describe the propagation of seismic waves, which can lead to inaccurate positioning of deep events during imaging. On the basis of the TTI medium elastic wave equation, this paper sets the shear wave velocity to a smaller value and introduces a source loop to eliminate pseudo shear wave artifacts. On the other hand, logging data is used to constrain and correct the parameters field, in order to improve the imaging accuracy of deep and complex structures. The reverse time migration(RTM) method can have an impact on imaging due to low-frequency noise. Therefore, based on the Laplacian filtering operator for denoising, the paper extracts the angle domain common imaging point gathers(ADCIGs) and uses angle-selected stacking imaging to suppress strong amplitude low-frequency noise caused by inaccurate migration parameters. The real data requires a large amount of computation during imaging. In this article, the CPU/GPU cooperative operations are used to accelerate migration and improve computational efficiency. The model and real data results show that the TTI-RTM method based on logging data constraints can accurately image deep and complex structural target areas, which also proves the feasibility of the method.

10.11885/j.issn.1674-5086.2024.04.17.03