Steel Coiled Tubing Defect Evaluation Using Magnetic Flux Leakage Signals

Liu, Zhanke; Minerbo, Gerald; Zheng, Andrew

doi:10.2118/168260-ms

Cited by 7 publications

(1 citation statement)

References 26 publications

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“…On the other hand, NDT inspection results are primarily qualitative and have not been fully integrated with computer-based fatigue modeling and tracking. In recent years, effort has been devoted to deriving quantitative information from MFL measurements regarding the defect geometry (Breidenthal et al 2006;Liu et al 2014). More recently, progress has been made in establishing the scaling between fatigue-life ratio and MFL measurements for typical mechanical type defects .…”

Section: Introductionmentioning

confidence: 99%

A Hybrid Approach of Coiled Tubing Fatigue Assessment Considering Effects of Localized Damage Based on Magnetic Flux Leakage Measurements

Liu

Kenison

Campbell

2016

Day 1 Tue, March 22, 2016

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In the coiled tubing (CT) business, it is a common practice to track the fatigue-life of CT strings to help avoid costly failures during operations. Existing fatigue-life tracking models account for parameters such as differential pressure, bending radius, tubing diameter, wall thickness, and materials grade. However, these models do not take into account the effect of localized damage, which is the leading factor contributing to premature failure. In the past years, models have been developed to account for the fatigue effects of mechanical defects. A key input for such models is the geometrical severity parameter, which is defined as a function of the defect geometries (length, width, depth, and shape). Normally, these inputs must come from manual measurements and prove-up. Most recently, a new technique was developed which does not rely on the manual measurements. The new technique utilizes inline magnetic flux leakage (MFL) technology to automatically determine the defect severity in terms of fatigue-life reduction.The current paper presents new development and results of enhanced fatigue evaluation by virtue of MFL measurements. A hybrid approach is proposed and demonstrated, in which the results of conventional fatigue tracking are coupled with the fatigue-life reduction determined based on MFL measurements on physical defects, to come up with a more comprehensive and accurate fatigue-life assessment. Experimental results are presented to support the validity of this hybrid approach. Also, the new approach is applied on a number of case studies to demonstrate its applicability in real-world CT pipe management.

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Section: Introductionmentioning

confidence: 99%

A Hybrid Approach of Coiled Tubing Fatigue Assessment Considering Effects of Localized Damage Based on Magnetic Flux Leakage Measurements

Liu

Kenison

Campbell

2016

Day 1 Tue, March 22, 2016

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A Novel Fatigue Assessment of CT with Defects Based on Magnetic Flux Leakage

Liu

Zheng

Diaz

et al. 2015

Day 1 Tue, March 24, 2015

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Conventional models have been proven to be successful in predicting the mechanical fatigue life of coiled tubing (CT) without defects. However, defects of various types, including mechanical, manufacturing or corrosion defects, on CT are commonplace in the real world. The impact of such defects on CT fatigue life has been widely recognized. Today's common practice heavily relies on prove-up and manual measurement of defect dimensions, to assess the defect severity on tubing integrity issues, such as fatigue life. Such practice tends to be inefficient, user-dependent, and inconsistent in fatigue and severity assessment; sometimes it's even not feasible in the case of internal defects. A novel defect severity analysis based on magnetic flux leakage (MFL) was used to quantitatively assess the CT fatigue life reduction due to mechanical defects. This new quantitative approach allows consistent, automated in-line fatigue analysis during operation, as it does not depend on a user's manual measurement of defect dimensions. The new model results compared well with experimental data. The analysis method was successfully used in fatigue assessment of realistic field defects.

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Extending Coiled Tubing String Utilization by Real-Time Field Inspections

Gallagher

Kemp

Hudson

et al. 2015

Day 2 Tue, November 10, 2015

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In volatile times, when oil prices are in a decline, efficiencies and asset utilization are critical elements to ensure sustainability in the market for both operators and service companies. However, maximizing utilization and pushing equipment to the maximum could potentially have negative repercussions and ultimately result in failures causing loss of time and other potential damages. Thus is it critical to closely monitor and evaluate the assets conditions to ensure both safe and efficient operations are performed. In the case of coiled tubing (CT) strings, monitoring and proper evaluation can be performed by utilizing an infield nondestructive evaluation (NDE) device that employs magnetic flux leakage (MFL) to detect flaws and monitor, wall thickness, outer diameter, and various other properties. The real-time device requires no direct contact with pipe, and its compact design allows it to be run continuously throughout the life of the CT. Damage can then be detected and managed before a failure occurs. The ultimate goal is to reduce CT failures while increasing CT longevity throughout the operations. This paper covers three specific examples of NDE inspection conducted on site that increased the utilization of the CT string without compromising the service quality delivery. It also reviews the various parameters that were monitored and evaluated on location and the decision-making process used to keep the strings in service longer than previous methods would have allowed thus safely increasing the utilization and improving the efficiency. The first two cases are out of Texas, USA. The objective of the NDE was monitoring the pipe for corrosion or physical plastic deformation. This region regularly performs high-pressure cycling operations and in the past relied mostly on calculated fatigue models with significant derated values and safety factors to retire strings from use. Utilizing the scanning devices from after manufacturing through the strings' life allowed both the operator and the service company get more useable footage and still retire the strings after getting indications of irreversible geometric changes. They were able to plan and control the CT retirement around operational well plans to ensure no delays were seen in the field. The third example is out of Alberta, Canada. A CT string being used on a long-term project was damaged. The NDE inspection allowed for continued use of a pipe that had visible surface damage. In the past, this string would have been immediately retired and removed from service after a mechanical defect of the same nature was observed; however, the NDE device aided in adressing the severity of the damage, by MFL, and monitored its progress while continuing to use the string. The 2.375-in. string was able to be run an additional 53,203-m [174,550-ft] in a safe and controlled manner before reaching retirement.

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Steel Coiled Tubing Defect Evaluation Using Magnetic Flux Leakage Signals

Cited by 7 publications

References 26 publications

A Hybrid Approach of Coiled Tubing Fatigue Assessment Considering Effects of Localized Damage Based on Magnetic Flux Leakage Measurements

A Hybrid Approach of Coiled Tubing Fatigue Assessment Considering Effects of Localized Damage Based on Magnetic Flux Leakage Measurements

A Novel Fatigue Assessment of CT with Defects Based on Magnetic Flux Leakage

Extending Coiled Tubing String Utilization by Real-Time Field Inspections

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