Agency: European Commission | Branch: FP7 | Program: BSG-SME | Phase: SME-2011-1 | Award Amount: 1.42M | Year: 2011
The Moorinspect project will bring a step change to the current in-water moor chain inspection systems through the development and introduction of new method for detection of fatigue cracks in the large chain links used in Deepwater offshore facilities. Moorinspect main objective would be to develop a medium range ultrasonic in-water testing technology using Ultrasonic Guided Waves (UGW) method to identify cracks and fatigues in closed circular/elliptical chains. Due to the propagation capability of the tool, it would also be possible to test link-cross sections in chain links for potential of detection of cracks in usually inaccessible locations, specific objectives would be to provide Interpretation of Signal readings for under surface crack and fatigues in chain links through development of UGW transducers ring, calibration techniques. The Moorinspect main technology objective would be to bring the novel approach to Non Destructive Testing (NDT) moor chain scanning though investigating several types of transducers for MRUT methods including (Electro-Magnetic Acoustic Transducer) EMAT approach to deployment, and hence through Development of Mechanised Deployment Vehicle to inspect those chains, leading to the capacity to conduct periodical inspection to detect progressive defects and fatigues based on historical data gathered from perpetual testing.
Clough M.,University of Warwick |
Clough M.,Sonomatic Ltd |
Dixon S.,University of Warwick |
Fleming M.,Sonomatic Ltd |
Stone M.,Sonomatic Ltd
AIP Conference Proceedings | Year: 2016
Guided waves are now commonly used in industrial NDT for locating corrosion in pipelines in the form of wall thinning. Shear Horizontal waves generated by EMATs are used in a screening arrangement in this work to locate and size corrosion in terms of axial extent and circumferential positioning. This is facilitated by propagating SH waves circumferentially around the pipeline whilst moving a scanning rig axially, keeping transducer separation constant. This arrangement is preferential in that it can operate through thin(up to 1mm) coatings and does not require full access to the pipe's circumference and is useful for detecting corrosion in difficult to access regions, such as below pipe supports and in subsea applications. The performance of the system in terms of screening capability and the possibilities of extension into more quantitative measures are assessed. The behaviour of different wave modes as they interact with defects is investigated via experimental measurements on artificially induced corrosion patches and measurements on samples with in service corrosion. Measurement of the axial extent of corrosion patches, circumferential positioning and a range of possible remaining thickness is assessed. Finite element modelling of SH mode interaction with defects is used to understand what happens to different wave modes when they interact with defects in terms of reflection, diffraction and mode conversion. © 2016 AIP Publishing LLC.
Osbeck S.,Robert Gordon University |
Osbeck S.,Sonomatic Ltd. |
Ward S.,Cytec Industries Inc. |
Idriss H.,Robert Gordon University |
And 2 more authors.
Applied Surface Science | Year: 2013
The adsorption properties of untreated, electrochemically treated and ultra-violet/ozone treated polyacrylonitrile based carbon fibres were investigated using temperature programmed desorption (TPD) on a series of linear alcohols as probes in order to understand its surface properties. Surface uptake was found to be sensitive to both the surface treatment and the nature of the adsorbates. Surface coverage increased with increasing alcohol chain due to the increase in their polarizability. It also increased with the level of surface oxygen of the fibres most likely because it facilitates the OH bond dissociation of the alcohol functional group. In addition, the desorption temperature (during TPD) tracked the surface oxygen levels (as determined from XPS O1s signal) suggesting increasing in the adsorption energy. The reactions of C1-C4 linear alcohols were also investigated on the surface of the fibre carbon. The main reaction was dehydrogenation to the corresponding aldehydes; the dehydration reaction to olefins was not observed. The dehydrogenation reaction was sensitive to the length of the alky chain. It was highest for methanol (to formaldehyde) and decreased with increasing the carbon number. Overall TPD of linear alcohols was shown to be a promising method for quantifying the level and strength of bonding occurring on carbon fibre surfaces. © 2013 Elsevier B.V.
Stone M.,Sonomatic Ltd
Insight: Non-Destructive Testing and Condition Monitoring | Year: 2011
Corrosion mapping, in which wall thicknesses over large areas are measured by 0 degree compression probe ultrasonics at closely-spaced points, is being used increasingly in oil and gas applications. This paper describes a new approach to statistical analysis based on wall thickness distributions derived from corrosion mapping data. The analysis methods developed are described and cumulative thickness distributions obtained in a wide range of field applications are presented. A range of situations in which corrosion of carbon steel is active are covered and the results include analysis of data from pressure equipment with CO2 corrosion, O2 corrosion, under deposit corrosion, naphthenic acid corrosion and corrosion under insulation. The results show that there are many situations in which the wall thickness distributions display strongly ordered behaviour. In many cases it is observed that the wall loss can be represented by an exponential distribution. Examples of wall loss distributions other than exponential are also provided. It is shown that the distributions established can be a useful basis for estimates for the uninspected areas when less than 100% coverage has been achieved. A summary covering applications of such analyses to integrity management practice is provided. This highlights the benefits of the use of underlying thickness distributions.
Lilley J.R.,Sonomatic Ltd.
Insight: Non-Destructive Testing and Condition Monitoring | Year: 2010
Code Case 2235 was originally issued by the American Society for Mechanical Engineering (ASME) Boiler and Pressure Vessel Code (B&PVC) Committee in 1996. Construction codes and standards are intended to ensure that pressure equipment and structures are designed, fabricated and tested to consistent quality standards in the interests of safety and reliability. The code cases carried the statement regarding qualification block(s) and shall contain a minimum of three flaws, oriented to simulate flaws parallel to the production weld's fusion line. Large numbers of technicians have been required by industry to work in accordance with the code cases and there has been a tendency to rush these through the certification process. It can also be concluded that, if applied in the spirit with which they are intended, the code cases can lead to a requirement for a large quantity of costly qualification blocks and high levels of qualification activity, which could have the potential to delay project timescales.
Stone M.,Sonomatic Ltd. |
Emslie C.,Sonomatic Ltd. |
Lilley J.,Sonomatic Ltd.
Corrosion Management | Year: 2011
Non-intrusive inspection (NII) offers a range of benefits compared to traditional internal visual inspection (IVI) approaches for pressure vessels. It allows effective inspection of equipment while in service which leads to an increase in plant availability. The costs and safety hazards of vessel entry are also avoided. There has been particular interest from the upstream oil and gas industry in the application of NII. This paper aims to summarise some important aspects of that experience and identifies key elements that are essential to effective NII. In particular it covers the need for a structured process, working within the context of industry recommended practice, the integration of which requires specific changes to existing integrity management systems. Examples of implementation of such a process covering initial assessment, workscope development, inspection implementation and post-inspection evaluation and analysis are provided. The importance of seamless integration of these steps is emphasised. The impact of the approach to the inspection element on integrity decision making is also covered. Some common pitfalls and abuses of NII are identified. It is concluded that NII offers significant benefits to operators with no compromise on integrity provided a sound approach is adopted.
Cawley P.,Imperial College London |
Cegla F.,Imperial College London |
Stone M.,Sonomatic Ltd
Journal of Nondestructive Evaluation | Year: 2013
There is increasing interest in the use of permanently installed monitoring systems to track the progress of corrosion. There is a choice between point thickness measurement systems, those that monitor the average thickness over a modest area, and large area monitoring systems that will detect relatively severe, localised corrosion. The relative merits of the different types of monitoring system are assessed for cases with different likely fractions of the total surface area affected by corrosion. If the wall loss is expected to be fairly uniform over the component surface then a small number of point sensors is the most attractive solution, whereas if the loss is likely to be highly localised at an unpredictable location and potentially severe, a large area monitoring system is most suitable. In the intermediate case of modest loss over a significant fraction of the surface, the choice is more complex. If the requirement is to detect relatively large wall loss that may be localised then the number of point sensors required increases substantially and the average thickness area monitoring systems appear to be more attractive. However, it is shown that corrosion distributions are frequently exponential, and this can lead to large maximum pit depths when the average wall loss is at the margin of detectability with current commercially available systems. © 2012 Springer Science+Business Media New York.
Benstock D.,Non destructive Evaluation Group |
Cegla F.,Non destructive Evaluation Group |
Stone M.,Sonomatic Ltd
Journal of the Acoustical Society of America | Year: 2014
In corrosion assessment, ultrasonic wall-thickness measurements are often presented in the form of a color map. However, this gives little quantitative information on the distribution of the thickness measurements. The collected data can be used to form an empirical cumulative distribution function (ECDF), which provides information on the fraction of the surface with less than a certain thickness. It has been speculated that the ECDF could be used to draw conclusions about larger areas, from inspection data of smaller sub-sections. A detailed understanding of the errors introduced by such an approach is required to be confident in its predictions. There are two major sources of error: the actual thickness variation due to the morphology of the surface and the interaction of the signal processing algorithm with the recorded ultrasonic signals. Parallel experimental and computational studies were performed using three surfaces, generated with Gaussian height distributions. The surfaces were machined onto mild steel plates and ultrasonic C-scans were performed, while the distributed point source method was used to perform equivalent simulations. ECDFs corresponding to each of these surfaces (for both the experimental and computational data) are presented and their variation with changing surface roughness and different timing algorithms is discussed. © 2014 Author(s).
Conder P.M.,Sonomatic Ltd. |
McDonald K.I.,Sonomatic Ltd. |
Stone M.,Sonomatic Ltd.
Society of Petroleum Engineers - SPE International Oilfield Corrosion Conference and Exhibition | Year: 2016
Corrosion models and the laboratory testing they are based on, give a measure of corrosion rate but not the spatial distribution of corrosion. Corrosion risk assessments can include information on areas that are more susceptible to corrosion and can give a measure of the probability of corrosion occurring, but when the corrosion is localized rather than general, they do not indicate whether the corrosion is evenly spaced or clustered or how the corrosion will develop in extent over time. To deliver inspection, which is both effective and efficient, requires an understanding of the spatial distribution of corrosion along with the fraction of wall area affected by corrosion. Historically low level sampling using Manual Ultrasonic Techniques (MUT) has formed the primary basis for inspection of pipework on offshore oil and gas assets. For extensive corrosion, low level sampling can be effective and cost efficient but for less extensive corrosion, higher coverage is required to reliably reflect the nature of the corrosion. Simulation of different spatial and depth distributions of corrosion, to reflect a range of base case scenarios, have been carried out in conjunction with simulations of different inspection strategies. Metrics have been developed to compare the effectiveness of different inspection strategies. This paper discusses the aims of inspection and how efficient and cost effective the different inspection strategies, such as sampling or screening, are in meeting these aims. A range of different corrosion base cases including general uniform, random localized and preferential locations will be examined in relation to the most appropriate inspection strategy, defined primarily in terms of coverage. Recognizing these different corrosion cases from previous inspection results and the optimum time to change inspection strategy will also be covered. This paper quantifies the relationship between spatial distribution of corrosion in pipework and the effectiveness of different inspection strategies. Copyright 2016, Society of Petroleum Engineers.