Estimation elastic properties on core samples using ultrasonic travel-time tomography measurement with robotics application: preliminary study on laboratory model

Abstract

Ultrasonic travel-time tomography using laboratory model were performed in this preliminary study. The measurement was calibrated using a known velocity laboratory model representing an iron with P-wave velocity (Vp) 5920 ms−1. Source and receiver transducers were equally spaced around the model. In the first measurement, the source position was at point 1, and receivers at points 2 to 16. In the second measurement, the source position was at point 2, and receivers at points 3 to 1. The measurements were repeated, and a total of 240 ray path were recorded. Then, the travel-time data inverted and reconstructed to get tomogram using a MSIRT (Modified Simultaneous Iterative Reconstruction Technique) algorithm. Each pixel tomogram represents a point velocity at ray path intersections. It is important to have at least one intersection for each pixel, so each pixel represents an average velocity. The use of robotic instrument provides precise and efficient results in data measurements despite errors between 1% and 3% at the time of motor rotation. The ultrasonic tomography using robotics equipment proves to be helpful in obtaining accurate measurement.