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Projects: Projects for Investigator
Reference Number	NIA_NGGT0044
Title	SCT Pipeline Inspection System
Status	Completed
Energy Categories	Fossil Fuels: Oil Gas and Coal(Oil and Gas, Refining, transport and storage of oil and gas) 100%;
Research Types	Applied Research and Development 100%
Science and Technology Fields	PHYSICAL SCIENCES AND MATHEMATICS (Metallurgy and Materials) 50%; ENGINEERING AND TECHNOLOGY (Mechanical, Aeronautical and Manufacturing Engineering) 50%;
UKERC Cross Cutting Characterisation	Not Cross-cutting 100%
Principal Investigator	Project Contact No email address given National Grid Gas Transmission
Award Type	Network Innovation Allowance
Funding Source	Ofgem
Start Date	01 January 2014
End Date	01 April 2016
Duration	27 months
Total Grant Value	£1,235,000
Industrial Sectors	Information Technologies
Region	London
Programme	Network Innovation Allowance
Investigators	Principal Investigator	Project Contact , National Grid Gas Transmission (100.000%)
Web Site	http://www.smarternetworks.org/project/NIA_NGGT0044
Objectives	To develop the SCT inspection system such that it can be used as complementary tool to other pipeline inspection systems such as ILI, DCVG and CIPS. 1. The identification of pipeline girth welds to an accuracy of 90% where the PD/2t >60MPa (a measure of hoop stress where P is pressure, D is diameter and t is the wall thickness). This applies for seamed and seamless pipe but not spiral welded pipe. 2. Obtaining the depth of a pipeline to an accuracy of +/- 100mm with reference to a control point. 3. Obtaining the lateral (central) position of a pipeline using survey grade GNSS (GPS) hardware and software incorporated into the SCT system to an accuracy of +/- 100mm with reference to a control point. 4. Development of the SCT software, to enable a stress profile of the pipeline to be obtained in terms of quantified stress in each stress concentration zone related to hoop stress and SMYS. 5. Identifying the position of Stress Concentration Zones (SCZs) on the pipe circumference. Progress the characterisation of SCZ features. 1. To undertake research and development and field trials on the SCT solution to enhance functionality in the key areas as listed in the objectives section. 2. To provide an inspection tool, to compliment ILI or OLi4, that is capable of lateral pipe location, definition of its pipeline depth and the identification of the location of girth welds for use by National Grid. 3. To identify and potentially develop any additional functionality or features as agreed as part of this project. To identify and recommend future development opportunities.
Abstract	The fundamental problem relates to pipelines which cannot be internally inspected and the secondary problem is the risk of corrosion, caused by disbondment of coating systems, primarily coal-tar enamel, on buried pipelines. Most of the gas transmission pipeline network is now beyond its original 40-year design life and the standard approach to identifying and controlling metal loss on buried pipelines is to conduct in-line inspection (ILI) surveys. Where sub-critical defects are detected by ILI, the level of cathodic protection (CP) is managed in conjunction with ‘Close Intervals Potential Surveys’ (CIPS), which are undertaken much more frequently. CIPS can detect the location of lowest potentials but cannot diagnose the nature of the corrosion and CP will do nothing to halt or delay the corrosion in a "shielded" corrosion cell. A shielded corrosion cell can occur where coal tar or other coating has disbonded, water is drawn by capillary action between the pipeline and its coating, allowing corrosion to take place but preventing CP current reaching the area. Within this "shielded" environment, corrosion will continue even where CP potentials appear to be compliant. National Grid is therefore required to either increase the frequency of ILI surveys or carry out invasive works to monitor and assess what could be a population of many thousands of sub-critical defects on the typical pipeline. Where a pipeline cannot be internally inspected an OLI4 survey is conducted consisting of CIPS in conjunction with a coating defect survey e. g. Pearson or DCVG (Direct Current Voltage Gradient). Where low CP potential areas coincide with open coating defects invasive works are undertaken. This technique cannot identify corrosion taking place beneath disbanded coating and does not identify dents or corrosion depth/orientation. Where cathodically shielded corrosion takes place metal loss will occur at a typical rate of between 0. 1-0. 2mm/year which could equate to a metal loss of between 4-8mm of pipe-wall in a 40year old pipeline with early onset of disbondment (this would equate to a 31-62% wall thickness loss on a typical 12. 7mm pipeline). Stage 1 - Instrumentation Revise the current Stress Concentration Tomography (SCT) software design base (continues over 24 months and at multiple stages)Independent review and verification of results from existing data Development of new calibration, verification and testing procedures Construct dedicated SCT system for field trials Construction of test rigs for laboratory and site trials Stage 2 - Experimental Study Laboratory based analysis of magnetic fields Test site based analysis of magnetic fields Girth welds - verification of model and accuracy Advanced Pipe Location - Depth and central position of the pipeline Stage 3 - Modelling development Girth welds - on site verification Advanced Pipe Location Laboratory and Site comparison work Weld and defect differentiation Stage 4 - Evaluation Girth welds - field verification of new models Advanced Pipe Location - finalise Finite Element Analysis (FEA) model At each of the main stages GL Noble Denton will provide an independent review and report in relation to the deliverables along with a final report outlining the results and making appropriate recommendations.Note : Project Documents may be available via the ENA Smarter Networks Portal using the Website link above
Publications	(none)
Final Report	(none)
Added to Database	11/12/18