Cement bond quality evaluations are essential for assessing zonal isolation between formation strata,providing crucial information for ensuring environmental and ecological safety in oil and gas exploitation,geotherma...Cement bond quality evaluations are essential for assessing zonal isolation between formation strata,providing crucial information for ensuring environmental and ecological safety in oil and gas exploitation,geothermal energy injection and geological carbon dioxide sequestration.In the past decade,the ultrasonic pulse-echo and pitch-catch logging techniques have emerged as effective and non-destructive methods for quantitatively eval-uating bond quality at both the casing-cement and cement-formation interfaces.This review presents a comprehensive overview of recent advancements in cement bond quality assessment based on ultrasonic mea-surements.Key developments include automatic waveform quality assessment,inversion techniques for mud and cement impedance,tool trajectory corrections,separation of flexural and extensional mode waves,machine learning-based extraction and enhancement of TIE waveforms,and imaging of the cement-formation interface using the reverse time migration approach.The review thoroughly explores the methodological principles and applications of these techniques,supported by synthetic datasets,full-scale physical well experiments,and field well data.Considering the recent progress in machine learning and the growing availability of advanced computational resources,we highlight the most significant achievements and ongoing challenges in data pro-cessing,while discussing the potential advancements these techniques could offer in the near future.展开更多
High cement bond quality is required to keep an oil well from hydraulic commu- nication between zones. In the cement bond evaluation, the ultrasonic echo method is widely used for its capability of channeling azimuth ...High cement bond quality is required to keep an oil well from hydraulic commu- nication between zones. In the cement bond evaluation, the ultrasonic echo method is widely used for its capability of channeling azimuth detection. Full waveforms reflected from the cased hole are simulated for different bonding conditions by the generalized transfer matrix method. Because of the high acoustic impedance of casing, the amplitudes of the reflected waves from the cement and the formation are small and cannot easily be used to evaluate the cementing condition. The wave that can propagate into the cement and the formation through the casing concentrates closely on the casing resonant frequency. To reduce the amplitude of the reflected wave from the casing inner surface and highlight the part of the reflected wave which carries the cementing quality information, the reflected full wave is filtered according to the casing resonant frequency. There are several wave packets in the filtered waveform. When the amplitude of the second wave packet is low, the cement bonds well with the casing, otherwise poorly. A low amplitude third wave packet is an indication of a good bond of the cement with the formation, otherwise poor. To reveal the sensitivity of the reflection wave amplitudes to the incident angle, reflected full waveform is modeled when an acoustic beam with finite width is incident on the casing. It is shown that the bond evaluation method based on filtered wave packets is valid for incident angle less than 5 degrees.展开更多
基金supported by a National Natural Science Foundation of China(Grant numbers 42474167,41974150,42174158,W2522002)Natural Science Basic Research Program of Shaanxi(2023-JC-YB-220)the Shenzhen Science and Technology Program(grant numbers JCYJ20230807120007015 and RCJC20231211085916003).
文摘Cement bond quality evaluations are essential for assessing zonal isolation between formation strata,providing crucial information for ensuring environmental and ecological safety in oil and gas exploitation,geothermal energy injection and geological carbon dioxide sequestration.In the past decade,the ultrasonic pulse-echo and pitch-catch logging techniques have emerged as effective and non-destructive methods for quantitatively eval-uating bond quality at both the casing-cement and cement-formation interfaces.This review presents a comprehensive overview of recent advancements in cement bond quality assessment based on ultrasonic mea-surements.Key developments include automatic waveform quality assessment,inversion techniques for mud and cement impedance,tool trajectory corrections,separation of flexural and extensional mode waves,machine learning-based extraction and enhancement of TIE waveforms,and imaging of the cement-formation interface using the reverse time migration approach.The review thoroughly explores the methodological principles and applications of these techniques,supported by synthetic datasets,full-scale physical well experiments,and field well data.Considering the recent progress in machine learning and the growing availability of advanced computational resources,we highlight the most significant achievements and ongoing challenges in data pro-cessing,while discussing the potential advancements these techniques could offer in the near future.
基金supported by the National Natural Science Foundation of China(41174110,41204092)
文摘High cement bond quality is required to keep an oil well from hydraulic commu- nication between zones. In the cement bond evaluation, the ultrasonic echo method is widely used for its capability of channeling azimuth detection. Full waveforms reflected from the cased hole are simulated for different bonding conditions by the generalized transfer matrix method. Because of the high acoustic impedance of casing, the amplitudes of the reflected waves from the cement and the formation are small and cannot easily be used to evaluate the cementing condition. The wave that can propagate into the cement and the formation through the casing concentrates closely on the casing resonant frequency. To reduce the amplitude of the reflected wave from the casing inner surface and highlight the part of the reflected wave which carries the cementing quality information, the reflected full wave is filtered according to the casing resonant frequency. There are several wave packets in the filtered waveform. When the amplitude of the second wave packet is low, the cement bonds well with the casing, otherwise poorly. A low amplitude third wave packet is an indication of a good bond of the cement with the formation, otherwise poor. To reveal the sensitivity of the reflection wave amplitudes to the incident angle, reflected full waveform is modeled when an acoustic beam with finite width is incident on the casing. It is shown that the bond evaluation method based on filtered wave packets is valid for incident angle less than 5 degrees.
