An Evaluation of Imaging-While-Drilling Technologies: A Comparative Study of Functionality, Applications, and Performance of Different Sensors

Abstract

Abstract Most logging-while-drilling (LWD) measurements can resolve azimuthal changes around the wellbore and create borehole images, which are useful for well placement, formation evaluation, drilling operations, and production. The resolution of the images varies depending on multiple aspects of the sensor design such as vertical resolution, acquisition rate, and the number of azimuthal sectors acquired. High-resolution images are utilized for reservoir characterization, fracture identification, and sedimentological research, whilst lower-resolution borehole images are employed for well placement and geomechanics. Multiple imaging sensors, including gamma ray, ultrasonic, micro-resistivity, and two different designs of density tool, were deployed in the same drilling bottom-hole assembly (BHA). The two density tools had different azimuthal resolutions (16 and 32 sectors), while the micro-resistivity sensor provided two different image resolutions, generating 1-in. and 0.4-in. resolution images with multiple detectors. More than 250 sectors, with a resolution of less than 0.2 in., were recorded by the ultrasonic imaging sensor. Data was acquired in multiple runs with the same BHA configuration, providing insight into time lapse analysis, wellbore deterioration with time, and fracture propagation after pumping acid into the wellbore following a stuck occurrence. The evaluation of multiple images acquired in different runs provided a valuable insight into the different sensors’ advantages and limitations. This study can be used as a comprehensive guide for the evaluation of LWD imaging tools.