Session: 03-03-08 Feature Assessment Case Studies – Selective Seam Weld Corrosion II

Date: Thursday, September 26, 2024
Time: 3:30 PM – 5:00 PM
Paper Number: 134060

TTC Energy (TCE) operates and maintains natural gas, refined products and crude oil pipelines in the USA, Canada and Mexico. The Natural Gas Pipeline network includes 92,600 kilometers (57,539 miles) of gas pipeline, transporting more than 25% of North American natural gas demand. In addition, TCE’s Liquids Pipelines division includes 4,900 kilometers (3,045 miles) of crude oil pipelines, shipping 590,000 barrels of crude oil per day, which is approximately 20% of the Western Canadian exports.

As part of its Integrity Management Program, TCE identified Selective Seam Weld Corrosion (SSWC) as one of the significant threats for certain seam weld types in their pipeline system. It also identified In-Line Inspection as the preferred methodology to address it. In that regard, multiple ILI vendors have claimed capabilities in detecting, identifying, and sizing SSWC features, which require careful evaluation and assessment.

TCE designed a pull-through testing exercise to statistically evaluate and validate those capabilities. The testing aims to test multiple ILI systems from different ILI vendors for SSWC and other threats that have not been validated before and to confirm the detection capabilities for specific pipe attributes. The final objective is to have an array of ILI vendors and technologies to address each threat cost-effectively.

The 24-inch diameter string constructed for this project included joints with synthetic and natural features, including SSWC, pits at the SW and in the pipe body, axial and circumferential slots in the pipe body, individual cracks, crack colonies, laminations, wrinkle bends, hard spots, dents with gouges and plain dents.

Five ILI systems from five ILI technology providers were tested.

The project included the pipe acquisition, the testing string design, the defect creation, the NDE and Lab evaluation of the reference data, the pull-through testing, the ILI vs Reference feature matching, and the statistical analysis of the results.

This paper presents the results of this study.

Presenting Author: Zain Al-Hasani TC Energy

Authors:

Zain Al-Hasani TC Energy
Pablo Cazenave Blade Energy Partners
Katina Jimenez Blade Energy Partners
Ryan Milligan Blade Energy Partners 

Session: 03-04-03 Integrity Management Program Improvements and Threat Management II

Date: Friday, September 27, 2024
Time: 8:30 AM – 10:00 AM
Paper Number: 131611

Determination of Safe Excavation Pressure During Hoe Ramming Activities

Abstract:

Hoe-ramming is a form of rock excavation where a percussion hammer is fitted to an excavator. During integrity excavations hoe ramming is sometimes used to break up large rocks to allow for easier rock removal from the area surrounding an in-service pipeline to enable the completion of integrity assessment activities. The method is often used when an area is too large for a jackhammer or where blasting is not possible or feasible. During integrity excavations, hoe ramming is typically used to remove rock around in-service natural gas pipelines to allow for access to complete assessment and repair activities.  

Reductions in the operating pressure to allow for a safe excavation can have impacts to pipeline operation requirements and can have commercial consequences. The current state when hoe ramming is contemplated a commensurate conservative reduction on pressure on the pipeline is applied. This is often based on a poor understanding of the effect of hoe ramming on the affected pipeline. Given this conservativism, an opportunity exists to enhance the understanding of the effect on the pipeline to allowing for a more informed safe excavation pressure.  

In this study, full-scale testing in conjunction with dynamic finite element analysis (FEA) was performed, to help gain insight into the effect of and quantification of the effects of hoe ramming activities to an in-service natural gas pipeline. Testing was completed in December 2022 at the Pipeline Research Council International’s (PRCI) Technology Development Center in Houston, Texas. The testing included an NPS 24, GR359, 6.35mm NWT test pipe. The testing encompassed two configurations using granite blocks: i) test pipe on top of two granite blocks, and ii) test pipe on side of one granite.  Hoe ramming was executed on the granite blocks and the pipe response was measured. Some of the variables controlled during the testing were: i) the proximity of hoe ramming to the test pipe, ii) the internal pressure of the test pipe. Instrumentation, which included accelerometers and strain gauges, were installed on both granite blocks and the test pipe. The resulting test data was processed and analyzed to quantify the effects to the test pipe during the hoe ramming activities.  

The pipe response due the hoe ramming action from both the testing and the dynamic FEA simulation indicated that there was little no effect to the test pipe due to the Hoe ramming.  Dependencies such as proximity of hoe ramming to the pipeline and internal pressure were also investigated. The test results were used to validate the FEA simulation model of the tested configurations, which subsequently expanded to parametrical models to cover additional scenarios and to understand the influence of the critical variables. The outcomes of this study include the development of a pressure-equivalent model to help determine a safe operating pressure during hoe ramming activities. The impact of hoe ramming on defects sometimes encountered during an integrity investigation such as manufacturing flaws or metal loss (corrosion), cracking is also discussed. 

Presenting Author: Joe Saunders TC Energy

Authors:

Joe Saunders TC Energy
Mathew Jobin TC Energy
Elvis Sanjuan Riverol TC Energy
Ronald Chune TC Energy
Ken Zhang TC Energy
Ryan Milligan Blade Energy Partners

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