Industrial process tomography (PT) possesses unique advantages in multiphase distribution imaging. Oil–gas–water three-phase distribution has coexisting high-impedance contrast and low-impedance contrast medium, possessing a challenge to traditional PT sensing technique. An original concept of multifrequency ultrasonic tomography (MFUT) is proposed, which reconstructs oil–gas–water three-phase distribution with the single modality of UT. Operated in the transmissive ultrasonic tomography (UT) framework, the proposed MFUT quantifies attenuation spectrum response under frequency-modulated chirp signal excitation and extracts fluid absorption coefficient through partial differential modeling of frequency attenuation response. Artifacts introduced by lateral scattering is further alleviated through beam angle modification during assembling of the sensitivity matrix. Thus, the MFUT method is theoretically less sensitive to nonlinear error introduced by the reflection/refraction/scattering effect. In numerical and experimental results, quantitative attenuation characterization offers MFUT the capability of reconstructing gas–water/oil–water/oil–gas–water multiphase distribution with higher accuracy, boundary preservation, and image purity. Synthetic modeling of spectral attenuation also outperforms the single-frequency image fusion and frequency difference reconstruction, from which the MFUT is proven feasible to investigate a multiphase system.

中文翻译：

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使用透射衰减谱的油气水三相分布成像的多频超声层析成像

工业过程断层扫描 (PT) 在多相分布成像方面具有独特的优势。油气水三相分布同时存在高阻抗对比剂和低阻抗对比剂，对传统的PT传感技术提出了挑战。提出了多频超声断层扫描 (MFUT) 的原始概念，它以 UT 的单一模态重建油气水三相分布。所提出的 MFUT 在透射式超声断层扫描 (UT) 框架中运行，量化调频啁啾信号激励下的衰减频谱响应，并通过频率衰减响应的偏微分建模提取流体吸收系数。通过在组装灵敏度矩阵期间修改光束角度，可以进一步减轻由横向散射引入的伪影。因此，MFUT 方法理论上对由反射/折射/散射效应引入的非线性误差不太敏感。在数值和实验结果中，定量衰减表征为 MFUT 提供了以更高的精度、边界保留和图像纯度重建气-水/油-水/油-气-水多相分布的能力。频谱衰减的合成建模也优于单频图像融合和频差重建，从中证明 MFUT 可用于研究多相系统。MFUT 方法理论上对由反射/折射/散射效应引入的非线性误差不太敏感。在数值和实验结果中，定量衰减表征为 MFUT 提供了以更高的精度、边界保留和图像纯度重建气-水/油-水/油-气-水多相分布的能力。频谱衰减的合成建模也优于单频图像融合和频差重建，从中证明 MFUT 可用于研究多相系统。MFUT 方法理论上对由反射/折射/散射效应引入的非线性误差不太敏感。在数值和实验结果中，定量衰减表征为 MFUT 提供了以更高的精度、边界保留和图像纯度重建气-水/油-水/油-气-水多相分布的能力。频谱衰减的合成建模也优于单频图像融合和频差重建，从中证明 MFUT 可用于研究多相系统。