套管中环向传播的准SH波的衰减特征  

Attenuation characteristics of quasi-SH wave propagating circumferentially in a casing

作　　者：陈雪莲[1] 庄妍 殷晓康 唐晓明[1] CHEN XueLian;ZHUANG Yan;YIN XiaoKang;TANG XiaoMing(National Key Laboratory of Deep Oil and Gas,University of Petroleum(East China),Qingdao Shandong 266580,China;School of Mechanical and Electronic Engineering,China University of Petroleum,Qingdao Shandong 266580,China)

机构地区：[1]深层油气全国重点实验室(中国石油大学(华东)),山东青岛266580 [2]中国石油大学(华东)机电工程学院,山东青岛266580

出　　处：《地球物理学报》2023年第10期4402-4412,共11页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41774141,41821002);中石油重大科技项目(ZD2019-183-004)资助。

摘　　要：套管井中的准SH波测井可有效解决声阻抗类声波仪器在低密度水泥胶结评价上的不适应性.本文结合解析计算、三维数值仿真和实验测量研究了套管中环向传播的准SH波的衰减特征.数值仿真和实验测量结果均表明准SH波的衰减主要由波传播过程中的几何扩散和向套管后胶结的固体水泥泄漏能量引起的;解析计算显示在0~300 kHz的测井频段随着频率的增加零阶准SH波的泄漏衰减逐渐增大、一阶准SH波的泄漏衰减逐渐减小,在现有油气井使用的水泥阻抗范围内,准SH波的衰减与水泥阻抗成正比.数值仿真和实验测量的零阶准SH波的衰减与解析计算结果吻合,一阶准SH波的衰减稍高于解析计算结果.另外在实验测量过程中记录了水泥从浇筑到逐渐凝固过程中准SH波测井的全波波形,可清晰观测到直达的准SH波在水泥未凝固前(仍是流体)幅度较强,随着水泥逐渐凝固强度增大准SH波的泄漏衰减逐渐增加,泄漏到水泥环中的能量越来越强,来自水泥外界面的反射波幅度逐渐增加且到时逐渐提前.通过理论计算和实验测量套管井SH横波的衰减特征,为现场应用SH横波测井评价套管井水泥胶结质量奠定基础.Quasi-SH wave logging in cased well can effectively solve the inadaptability of acoustic impedance instruments in the evaluation of low density cement bond.In this paper,the attenuation characteristics of quasi-SH wave propagating circumferentially along a casing are studied by combining analytical calculation,three-dimensional numerical simulation and experimental measurement.Both numerical simulation and experimental simulation results show that the attenuation of quasi-SH waves are caused by geometric diffusion and energy leakage during wave propagation.The analytical calculation shows that the leakage attenuation of zero-order quasi SH wave increases gradually and the leakage attenuation of first-order quasi SH wave decreases with frequency increasing.In the impedance range of cements used in existing oil and gas wells,the attenuation of quasi SH waves is proportional to the cement impedance.The attenuation values of the zero-order quasi SH wave extracted from numerical simulation and experiment measurement agree with the analytical calculation results,and the attenuation of the first-order quasi SH wave is slightly higher than the analytical calculation results.Also the experimental waveforms were recorded during the process of cement gradual solidification.It can be clearly observed that the amplitude of quasi SH wave is the strongest at the initial stage of cement pouring,and as cementing time increasing,cement bonding strength increases gradually and leakage attenuation of quasi SH increases.The amplitudes of the reflected wave from the outside of the cement sheath gradually increase and the arrival time is gradually earlier and earlier.The study on the attenuation characteristics by theoretical calculation and experiment measurement lays a foundation for evaluating the cement bonding quality in cased wells by using SH shear wave logging.

关 键 词：准SH波测井 泄漏衰减 几何扩散 套管井 

分 类 号：P631[天文地球—地质矿产勘探]