井下前视声波偏移聚焦成像方法

An acoustic imaging system of migration technique used in borehole

介绍了一种可用于检测油井套管形态的前视声波成像方法。本方法采用由多个独立阵元组成的面阵式换能器,每个阵元均能独立发射,将所有阵元接收的波形数字化后,采用偏移聚焦成像方法,实现井下油井套管形态的前视声波三维成像。本文对数字偏移聚焦成像的基本原理进行了介绍,并用数值模拟和成像实验进行验证。表明本方法能够在阵元个数有限的情况下得到具有较高分辨率的图像,并可以简化井下仪器的电路结构。

In order to detect the damage of casing boreholes, an acoustic imaging method with a two-dimensional ultrasonic array is presented. Each element of the array independently emits down ultrasonic waves, the echoes received by all elements are sampled and transmitted to a computer on ground surface, where the dynamic migration method is used to form a 2 or 3-dimensional image of the situation in the borehole. The numerical simulation and experiment are conducted that demonstrate a high imaging accuracy with a small number of elements used in array. Since the delay circuits used in the traditional phase array imaging system is not needed in this system, and all data process could be completed in a ground system, the complexity and the volume of system in borehole may be significantly simplified, which is critical to the borehole instrument.