测井技术2025，Vol.49Issue(2)：209-217,9.DOI:10.16489/j.issn.1004-1338.2025.02.008
基于解耦波场的套管井超声弯曲波测井逆时偏移成像
Time Reversal Imaging of Ultrasonic Pitch-Catch Measurements Based on Decoupled Wavefields in Cased Hole
摘要
Abstract
Cased-hole ultrasonic pitch-catch logging serves as a critical quantitative detection method in cement bond evaluation,primarily employed for the quantitative assessment of bonding quality at both casing-cement and cement-formation interfaces.Conventional reverse time migration(RTM)with coupled acoustic field cross-correlation imaging conditions often generates significant artifacts near real reflection interfaces.These artifacts arise from the complex characteristics of formation interface reflections in actual acquisitions,containing multiple seismic phases,which consequently interfere with accurate identification of the true cement-annulus-formation interface.To address this challenge,this study proposes a Helmholtz decomposition-based methodology.The approach establishes an improved RTM imaging method for cased-hole ultrasonic flexural waves through wavefield decoupling of both forward and backward propagated wavefields at each timestep,incorporating decoupled wavefield auto-correlation and cross-correlation operations.Synthetic case studies demonstrate that the auto-correlation RTM results of decoupled S-wave fields exhibit enhanced energy concentration at theoretical reflection interfaces when the annular medium is conventional cement,accompanied by significant reductions in imaging artifacts and noise.Therefore,the proposed decoupled wavefield RTM method provides an effective solution for high-precision imaging of cement-annulus-formation interfaces in cased-hole measurement environments.关键词
套管井/超声弯曲波测井/逆时偏移成像(RTM)/Helmholtz分解/解耦波场Key words
cased hole/ultrasonic pitch-catch logging/reverse time migration(RTM)/Helmholtz decomposition/wavefield decomposition分类
天文与地球科学引用本文复制引用
李萌,王华,李佳乐,母若瑶..基于解耦波场的套管井超声弯曲波测井逆时偏移成像[J].测井技术,2025,49(2):209-217,9.基金项目
国家自然科学基金项目"套管井非轴对称超声声场特征与数据处理方法研究"(41974150) （41974150）
国家自然科学基金项目"套管井非轴对称声场特征及水泥环空速度剖面智能成像方法研究"(42174158) （42174158）
国家自然科学基金项目"非轴对称双层套管井声场特征分析及实验研究"(42474167) （42474167）
陕西省自然科学基金项目"MPI和CUDA混合加速的微地震解耦波场最小二乘逆时干涉震源定位方法研究"(2023-JC-YB-220) （2023-JC-YB-220）
