What Is Magnetic Thickness Tool？

The Magnetic Thickness Tool is a logging tool used to record the changes in high-energy electromagnetic pulse response. The metal presence around the instrument is evaluated by matching the measurement and numerical simulation of the magnetization attenuation. The attenuation of the air response is faster than that when the instrument is placed in a metal tube. If there are multiple pipe columns around the tool, the proximal pipe column will respond earlier, while the farther pipe will respond later. This phenomenon is key to detecting the metal in each individual pipe column and independently distinguishing the defects in each pipe column.

It has complex temporal characteristics and cannot be modeled in a simple analytical way, which has put time-domain technology on hold for many years. With the latest advancements in computer speed and multi-core parallel computing technology, precise numerical modeling of complex responses has been achieved, and the metal content of multi-layer pipe strings has been determined respectively. In addition to the thickness distribution maps of each layer, the tool also generates differential (DELTA) data templates based on differences, visualizing between the numerical model and the actual response.

By comparing the simulated attenuation with the actual response, the wall thickness of the first, second and third pipe columns can be calculated. In fact, if the calculation of the system's response to magnetic interference is simplified to calculating the magnetic field intensity near the receiving coil, the shape of the electromagnetic field will be described as the following two Maxwell equations:

The response parameters (amplitude and attenuation time) are usually composed of the geometric parameters of the casing and tubing (radius d - wall thickness h) as well as the electromagnetic parameters (μ and σ) of the casing and tubing. Therefore, the attenuation time can be roughly expressed as the product of d·μ·σ. The thicker the pipe wall, the longer the response attenuation time.

The logging data processing of Magnetic Thickness Tool adopts the CIF2020 software. The main functions are to calculate the thickness of the pipe, correct the electromagnetic structure changes of the pipe string, check the influence of the eccentricity of the pipe string, and image the two-layer pipe string.

When processing the data, more than 240 secondary induced electromotive force curves and parameters such as the outer diameter, wall thickness, steel grade and the depth down to the well of the oil and casing need to be input.

After processing the data, the following results can be provided: damage and corrosion conditions of the pipe string, wall thickness of the oil pipe and casing, and imaging spectra of the two-layer pipe string.

The purpose of Magnetic Thickness Tool logging is to know the deformation or corrosion of the pipe string in the well, providing a basis for the next operation.

Welcome to contact us to learn more about our tools via e-mail info@a-oneoil.com