Onshore pipeline pressure isolation that is cost-effective and environmentally friendly? What may seem like a too-good-to-be-true possibility is turning into a reality for operators. Ahmed Hassanin is leading a project that is validating pressure isolation technologies for thin-wall gas transmission pipelines.
The comprehensive validation project combines full-scale testing and finite element analysis (FEA) for the safe and effective application of pressure isolation tools. The pressure isolation techniques that have become common practice for offshore pipelines may be shown to work for thinner-walled pipelines and present additional economic and environmental benefits.
The technology developed by isolation plug companies can be deployed through standard pigging procedures and used in tandem with other plugging tools or with other components, such as valves. The tools can be controlled remotely and landed precisely at specific locations of interest. Once it is positioned at the desired location, hydraulically-actuated grips lock the tool to the pipe wall. Sets of packers/seals radially expand to provide a pressure seal within the pipe to isolate the area for repairs.
To validate the tool for use by operators, the project aims to determine: 1) the stress of the tool on the walls of the pipe, 2) the effect of tool engagement on present seam welds, and 3) the leak tightness of the seal. The desired results attempt to show the theoretical and actual stresses/strains in the pipe wall do not exceed maximum allowable limits and do not affect seam welds on the pipe.
The first phase of the project is the FEA to understand the theoretical response. Those results will be compared to the actual response in the full-scale testing phase. Finally, the results of the full-scale testing will be used to validate the numerical models. Ahmed has already seen generally positive indications of the potential success of the tool in the FEA phase of this project.
“Through finite element analysis, we were able to gain a better understanding of what the reaction of the pipe would be to the added load when the tool is expanded,” Ahmed said. “If the next few phases return similarly positive responses, it may indicate an opportunity for the pipeline operator to add a safe, cost-effective and environmentally friendly tool to their integrity management toolkit.”
One of the most interesting potential benefits of applying this tool to thin-wall pipelines is the positive environmental impact. As Environmental, Social, Governance (ESG) initiatives become more top-of-mind for operators, opportunities to improve ESG scores may present significant advantages.
“Currently, we see hot-tapping used in situations where the pressure isolation tool might provide advantageous applications for pressure isolation,” Ahmed said. “As we use full-scale testing and numerical modeling to validate this technology, it may provide operators the opportunity to reduce greenhouse emissions due to lower blowdowns while also avoiding the large dig-related expenses.”
The full-scale testing phase of the project will make use of ADV Integrity’s Digital Image Correlation (DIC) camera and strain gauge measurements to measure the hoop strains on the pipe wall from the pressure isolation tool. The project will resemble a previous project completed by ADV Integrity for Pipeline Research Council International (PRCI).
New applications and new methods are what drive the industry forward. ADV Integrity’s full-scale testing and numerical modeling capabilities are well equipped to continue validating the technology that could have a positive impact on pipeline integrity and operations. With ADV Integrity’s engineered testing solutions and consultations, operators can ensure safe and effective applications of advanced technologies.
Originally published on March 30, 2022