Quantitative Evaluation of Multi-Annular Downhole Corrosion Using Time-Domain Electromagnetic Measurements

2021 ◽  
Author(s):  
Sushant M. Dutta ◽  
Pervaiz Iqbal ◽  
Joseph Olaiya ◽  
Vladislav Danilenko
Keyword(s):  
High Resolution ◽  
Magnetic Flux ◽  
Case Studies ◽  
Quantitative Evaluation ◽  
Eddy Current ◽  
Eddy Currents ◽  
Magnetic Flux Leakage ◽  
Pulsed Eddy Current ◽  
New Instrument ◽  
Flux Leakage

Abstract A novel electromagnetic instrument is presented that uses transient or pulsed eddy current measurements to perform quantitative evaluation of downhole corrosion in four concentric tubulars individually, and to inspect a fifth tubular qualitatively. Case studies are presented that compare results from this instrument with industry-standard single-string evaluation tools such as multi-finger calipers and high-resolution magnetic flux leakage tools. The new instrument is based on transient or pulse eddy current technology and comprises three highly sensitive sensors that simultaneously achieve high-resolution of the inner barrier and high radial depth of investigation for up to five barriers. Each sensor induces coaxial rings of eddy currents in multiple concentric tubulars and measures a time-varying response from the outward-diffusing eddy currents. The full transient responses from multiple sensors are then interpreted to obtain individual tubular thickness profiles. Case studies are presented where the thickness profiles of outer barriers are obtained with the new instrument and are compared with high-resolution benchmark logs of multi-finger calipers and magnetic flux leakage tool. The benchmark logs were measured when the outer barrier was directly accessible because, either the inner barriers were not yet present, or the inner barriers were removed. These comparisons show that the new electromagnetic instrument is able to provide accurate individual tubular corrosion evaluation while logging through tubing. This ability is invaluable for proactive well integrity management because electrochemical corrosion, which is the primary corrosion mechanism in these wells, causes the outermost casing to fail first and then continues to penetrate inwards. Therefore, the new electromagnetic instrument enables early diagnosis of the outer tubulars to identify potential weak zones in the completion string while logging through tubing and eliminating the cost of pulling completions for this purpose. This paper describes the advantages and limitations of state-of-the-art multi-sensor pulsed eddy current measurements for individual barrier thicknesses of four or five strings. New case studies with high-resolution magnetic flux leakage tools and multi-finger calipers support these conclusions.

Practical evaluation of velocity effects on the magnetic flux leakage technique for storage tank inspection

2020 ◽  
Vol 62 (2) ◽  
pp. 73-80
Author(s):  
A L Pullen ◽  
P C Charlton ◽  
N R Pearson ◽  
N J Whitehead
Keyword(s):  
Magnetic Flux ◽  
Storage Tank ◽  
Eddy Currents ◽  
Surface Defects ◽  
Signal Amplitude ◽  
Magnetic Flux Leakage ◽  
Scanning Velocity ◽  
Near Surface ◽  
Practical Evaluation ◽  
Flux Leakage

Magnetic flux leakage (MFL) is a technique commonly used to inspect storage tank floors. This paper describes a practical evaluation of the effect of scanning velocity on defect detection in mild steel plates with thicknesses of 6 mm, 12 mm and 16 mm using a fixed permanent magnetic yoke. Each plate includes four semi-spherical defects ranging from 20% to 80% through-wall thickness. It was found that scanning velocity has a direct effect on defect characterisation due to the distorted magnetic field resulting from induced eddy currents that affect the MFL signal amplitude. This occurs when the inspection velocity is increased and a reduction in the MFL signal amplitudes is observed for far-surface defects. The opposite applies for the top surface, where an increase is seen for near-surface MFL amplitudes when there is insufficient flux saturating the inspection material due to the concentration of induced flux near the top surface. These findings suggest that procedures should be altered to minimise these effects based on inspection requirements. For thicker plates and when far-surface defects are of interest, inspection speeds should be reduced. If only near-surface defects are being considered then increased speeds can be used, provided that the sensor range is sufficient to cope with the increased signal amplitudes so that signal clipping does not become an issue.

Geometric Magnetic and Discriminator Sensor for Smart Pigs

2004 ◽  
Author(s):  
Vinicius de C. Lima ◽  
Jose´ A. P. da Silva ◽  
Jean Pierre von der Weid ◽  
Claudio Soligo Camerini ◽  
Carlos H. F. de Oliveira
Keyword(s):  
High Resolution ◽  
Magnetic Flux ◽  
Magnetic Flux Leakage ◽  
Metal Loss ◽  
Research Partnership ◽  
Technical Aspects ◽  
Pipeline Inspection ◽  
Catholic University ◽  
Laboratory Results ◽  
Flux Leakage

A result of a research partnership between Catholic University of Rio de Janeiro – PUC-Rio, PETROBRAS and PIPEWAY is presented: The development of an innovative sensor head for high resolution MFL Pigs, the GMD sensor, Geometric Magnetic and Discriminator. This head makes high resolution magnetic pipeline readings using the MFL - Magnetic Flux Leakage technique, with the addition of geometric readings and the outside/inside defects discriminations. This technique makes possible, with only one crown of GMD sensors, the caliper, metal loss and outside/inside discrimination pipeline inspection. Technical aspects of the development, e.g.: the construction details of the sensor, evaluation tests and laboratory results are also presented.

Management of Pipeline Dents and Mechanical Damage in Gas Pipelines

2006 ◽  
Author(s):  
David J. Warman ◽  
Dennis Johnston ◽  
John D. Mackenzie ◽  
Steve Rapp ◽  
Bob Travers
Keyword(s):  
High Resolution ◽  
Magnetic Flux ◽  
Mechanical Damage ◽  
Management Plan ◽  
Magnetic Flux Leakage ◽  
Pipeline System ◽  
Channel Geometry ◽  
Channel Deformation ◽  
Integrity Management ◽  
Flux Leakage

This paper describes an approach used by Duke Energy Gas Transmission (DEGT) to manage dents and mechanical damage as part of its overall Integrity Management Plan (IMP). The approach provides guidance in the process for evaluating deformation anomalies that are detected by high resolution magnetic flux leakage (HR-MFL) and multi-channel geometry in-line inspection tools, the process to determine which deformations will be selected for excavation, the process to conduct pipeline field excavations, assessments, and repairs for pipeline integrity purposes. This approach was developed, tested and fully implemented during pipeline integrity work over a two year program involving over 1,100 miles of HR-MFL and 900 miles of geometry in-line inspection. Integration of data from high resolution ILI tools (HR-MFL and multi-channel deformation tools) was used to identify and characterize dents and mechanical damage in the pipeline system. From subsequent field assessments and correlation with ILI results, the processes were refined and field procedures developed. The new guidance provided in the 2003 edition of ASME B31.8 was used as the governing assessment criteria.

Operator Assessment of ILI Defects

2006 ◽  
Author(s):  
Kevin W. Ferguson
Keyword(s):  
High Resolution ◽  
Magnetic Flux ◽  
Effective Area ◽  
Magnetic Flux Leakage ◽  
Burst Pressure ◽  
Final Report ◽  
Allocation Of Resources ◽  
Flux Leakage

With the age of the original Panhandle Eastern Pipeline (PEPL) Company pipelines, it’s not a matter of if anomalies will be found when an ILI tool is run, it’s a matter of how many and how severe. When a final report is received from an ILI vendor, burst pressures are typically calculated using Modified B31G, 0.85dL. The results can seem unmanageable, but success has been had doing further assessments on some anomalies without excavating them all. This assessment has been developed and performed by PEPL on three sets of Tuboscope ILI data and one set of Baker Hughes CPIG data. The method to be discussed was first employed in 2002. It provides a more accurate characterization of the defect and provides the company the ability to more effectively allocate resources. Efforts have been made to review the color scan of a vendor’s raw High Resolution Magnetic Flux Leakage (HRMFL) data, and perform an assessment using Effective Area Analysis without excavating hundreds of anomalies that prove no threat to the pipeline. This assessment is done by hand on the computer and in many cases returns a burst pressure higher than that calculated using Modified B31G, 0.85dL. The following is a case study that shows how multiple defects have been assessed prior to excavation in an attempt to more accurately characterize the defect, and allow for a better allocation of resources. Digs have been performed to validate the process, and the results will be discussed.

API 579 Level 3 Assessment of Dents Using High-Resolution ILI Data

2011 ◽  
Author(s):  
Chas Jandu ◽  
Mike Taylor ◽  
Suji Narikotte
Keyword(s):  
High Resolution ◽  
Magnetic Flux ◽  
Single Channel ◽  
Mechanical Damage ◽  
Magnetic Flux Leakage ◽  
Metal Loss ◽  
Operating Pressure ◽  
Data Set ◽  
Level 3 ◽  
Flux Leakage

In-line Inspection (ILI) surveys are periodically performed to determine the condition of the pipeline. Typical ILI surveys involve Magnetic Flux Leakage primarily to determine metal loss and simple single channel Calliper surveys to determine any signs of geometry imperfections. Additional surveys such as high-resolution multi-channel Calliper deformation tools are occasionally used to accurately record imperfections to enable a more accurate assessment of the integrity of the pipeline containing the imperfection. Such tools have had limited employment, and therefore little experience exists of using the data obtainable for the detailed assessment of defects. This paper presents a study of such a case. As part of an In-line Inspection (ILI) of an offshore pipeline, a high-resolution deformation survey recorded numerous dent anomalies which had potentially resulted from a single dragged anchor incident before the pipeline was trenched. This data set was correlated to Magnetic Flux Leakage inspection data to confirm external mechanical damage. Pipeline sections having anomalies that were either found close to girth welds, or had associated corrosion defects were automatically selected for repair. The remaining anomalies were assessed in order to determine their acceptability for the maximum allowable operating pressure using the approaches detailed in API-579. Due to the sharp nature of some of the dents, elastic-plastic finite element analyses (FEA) were performed using denting profiles generated from the calliper data of the ILI run. API-579 level 3 assessments were then carried out using the FEA results. This paper details the high-resolution deformation tool findings and the approach used in order to assess the fitness-for-purpose of the pipe with the recorded anomalies.

Multiple cracks detection and visualization using magnetic flux leakage and eddy current pulsed thermography

2015 ◽  
Vol 234 ◽  
pp. 269-281 ◽  
Author(s):  
Yunlai Gao ◽  
Gui Yun Tian ◽  
Kongjing Li ◽  
Juan Ji ◽  
Ping Wang ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Eddy Current ◽  
Magnetic Flux Leakage ◽  
Multiple Cracks ◽  
Pulsed Thermography ◽  
Flux Leakage
Sign in / Sign up

Export Citation Format

Share Document