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Integrated coiled tubing inspection system

IP.com Disclosure Number: IPCOM000125941D
Publication Date: 2005-Jun-23
Document File: 4 page(s) / 153K

Publishing Venue

The IP.com Prior Art Database

Abstract

This invention uses Magnetic Flux Leakage Theory via utilizing magnets to detect defects on the CT. Magnetic flux lines joining north pole(s) and south pole(s) of magnet(s) saturate the CT locally. When material defects such as pin holes located at the ID or OD is in between the magnets, magnetic flux lines leak to the air, which has a lower magnetic permeability, compared to the CT. Similarly, mechanical defects change the permeability of the CT, which is a ferromagnetic material, therefore, magnetic flux lines leak. Special sensors facing the CT outputs voltage proportional to the magnetic flux lines they capture. At the defective areas of tubing, sensors give voltage spikes that indicate potential problems.

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Integrated coiled tubing inspection system

Introduction

Purposed Magnetic Flux Leakage (MFL) and ultrasonic device can give us the ability to detect material and mechanical defects at the coiled tubing (CT) inner and outer surface (ID and OD defects). The device discussed herein is simply operated compared to the other solenoid enabled magnetization systems. Its light and distinct way of magnetization schema enables practical mounting on the CT string. Its magnetization unit does not need a power supply, which makes the unit lighter. Device is composed of various components to detect defects, alarm the operator, mark an indicator on the suspected point, double check suspected surface area, make OD and ovality measurements, determine the location of defect along the CT.

Summary of the Invention

This invention uses Magnetic Flux Leakage Theory via utilizing magnets to detect defects on the CT. Magnetic flux lines joining north pole(s) and south pole(s) of magnet(s) saturate the CT locally. When material defects such as pin holes located at the ID or OD is in between the magnets, magnetic flux lines leak to the air, which has a lower magnetic permeability, compared to the CT. Similarly, mechanical defects change the permeability of the CT, which is a ferromagnetic material, therefore, magnetic flux lines leak. Special sensors facing the CT outputs voltage proportional to the magnetic flux lines they capture. At the defective areas of tubing, sensors give voltage spikes that indicate potential problems.

Detailed Description of the Invention

Flaw detection part of the proposed device is composed of following parts:

Magnetizing element: Four half circular ring magnets can be employed to magnetize the CT homogenously. Two of each magnet forms a circle around the CT. Rectangular magnets circumferentially surrounding the CT can be used as another means of magnetization. More than two pairs of circular magnets or more than two layers of rectangular magnets circumferentially around the CT can be employed, too. The distance between the pairs of magnets, the lift-off length of the magnets from the CT, and the type, size and grade of the magnets is crucial and determined after many tests. Magnets are capable of inspecting various sizes (OD and thickness) of CT.

Sensors: There can be two types of arrays of sensors. First array type can incorporate sensors with the sensing surface located radial. Therefore, radial components of flux leakage signals can be sensed. The second array can have sensing surface axial to the CT. Axial component of the leakage can be sensed in this case. Additional array of sensors of the same types are for verification purposes.

DAQ and transfer system: Data can be acquired from the sensors with an off the shelf DAQ board and transmitted to a laptop or hand-held device wireless. Another method could be analog transmission of the signals.

Housing: Magnetization unit, sensors, DAQ boards (if necessary), and cable outputs c...