Pipeline Integrity Management: Estimating and Prioritizing the Risk Resulting From Pipeline Facility Operations

Recent efforts to develop a consistent approach to understanding the risk associated with operating a cross country pipeline have focused primarily on the pipe itself. Integrity management plans often include a prioritized risk profile that all but ignores the specific risks associated with operating tank farms, terminals, pumps and compression. This paper outlines a detailed logical approach that can be utilized to evaluate the relative safety, environmental and cost risk associated with operating diverse types of equipment within a pipeline station. Topics covered include the basic objectives of a facility risk model while providing the detail (granulation) necessary to continuously improve. A specific methodology is suggested as a systematic tactic to make an “apples to apples” comparison of diverse stations, lines and types of equipment, from a risk standpoint.

Alarm Management for Pipelines

In 2005 the National Transportation Safety Board, concluded that an effective alarm review/audit system will increase the likelihood of controllers appropriately responding to alarms associated with pipeline leaks. This paper looks at the pipeline industry in the broader context of process industry alarm management and how the best practices of the process industry apply to the pipeline industry.

Projective Noise Reduction Algorithm for Negative Pressure Wave Signal Processing

The appearance of a rupture, leak or damage in the long-distance oil & gas pipeline, which could cause a leak, usually generates a non-linear & chaotic negative pressure wave signal. By properly interpreting the negative pressure wave signature, it is possible to detect a leak along the pipeline. Most traditional noise reduction methods are established based on the linear system, which are not in line with the actual non-linear & chaotic situation. Therefore, the weak negative pressure wave signals, generated by small leaks, are often filtered out and cause false alarm and failure alarm. In order to resolve the problem, this paper uses the non-linear projective algorithm for noise reduction. First, the weak negative pressure wave signal series would be reconstructed using delay coordinates, in the high dimensional phase space, the background signal, the negative pressure wave signal and the noise signal are separated into different sub-spaces. Through the reconstruction of sub-spaces, the weak pressure wave signal can be isolated from the background signal as well as the random noise component reduced.

Stress Analysis of a Gas Pipeline Installed Using HDD and Auger Bore Techniques

As part of an important project to reinforce the natural gas transmission network, a new pipeline has been constructed to transport natural gas from a major UK LNG storage facility into the national transmission system. The project involved the installation of several sections by trenchless methods, namely auger boring for a number of road crossings and significant lengths of horizontal directional drilling (HDD) beneath railroads, canals and marshland. The installation of pipelines using trenchless techniques such as HDD continues to increase in popularity. The various methods available offer advantages over traditional open cut techniques, in particular much reduced disruption during the construction of road and rail crossings. Furthermore, increased awareness and responsibility towards the environment leads us to seek installation methods that cause the least disruption at the surface and have the least impact to the environment. It was required to assess the proposed crossing designs against acceptable stress limits set out in company specifications and against the requirements of UK design code IGE/TD/1 Edition 4 [1], which requires that ‘additional loads’ such as soil loadings, thermal loads, settlement and traffic loading are accounted for within the stress calculations. However, it does not stipulate the sources of such equations and the pipeline engineer must rely on other methods and published sources of information. This paper presents the method used to analyse those sections of the new pipeline installed by auger boring and HDD focusing on the methods and formulae used to calculate the stresses in the pipeline from all loading sources.

Integration of Radio Frequency Identification and GIS for Asset Management

The use of Radio Frequency Identification (RFID) has grown substantially in the past few years. Driven mostly by the retail supply chain management industry and by inventory control (loss prevention), RFID technology is finding more acceptance in the security and personal tracking sectors beyond simple pass cards. This growth has of course resulted in greater acceptance of RFID technology and more standardization of process and systems as well as decreased per unit costs. The oil and gas industry is being exposed to the potential use of RFID technology, mostly through the safety and equipment inspection portion of construction management. However, the application of RFID technology is expected to expand to the material tracking and asset management realms in the near future. Integrating the information provided by RFIDs with EPCM project and owner/operator Geographic Information Systems (GIS) is a logical next step towards maximizing the value of RFID technology. By linking assets tracked in the field during movement, lay-down and construction to a GIS, projects will have accurate, real-time data on the location of materials as well as be able to query about those assets after commissioning. This same capability is being modified for post-commission use of RFID with facility GISs. This paper outlines how existing GISs used during the EPCM phases and those employed after commissioning can display, utilize and analyze information provided by RFID technology.

Implementation of a Pipeline Integrity Management System at TIGF (France): The Added Value of the Pipeline Threats and Mitigations Module

On January 4th 2007 TIGF published the following invitation for tenders: “Development and Provision of a Pipeline Integrity Management System”. The project was awarded to Bureau Veritas (BV), who proposed to meet the requirements of TIGF with the Threats and Mitigations module of the PiMSlider® suite extended with some customized components. The key features of the PiMSlider® suite are: • More than only IT: a real integrity philosophy, • A simple intuitive tool to store, display and update pipeline data, • Intelligent search utilities to locate specific information about the pipeline and its surrounding, • A scalable application, with a potentially unlimited number of users, • Supervision (during and after implementation) by experienced people from the oil and gas industry. This paper first introduces TIGF and the consortium BV – ATP. It explains in a few words the PIMS philosophy captured in the PiMSlider® suite and focuses on the added value of the pipeline Threats and Mitigations module. Using this module allows the integrity analyst to: • Prioritize pipeline segments for integrity surveillance purposes, • Determine most effective corrective actions, • Assess the benefits of corrective actions by means of what-if scenarios, • Produce a qualitative threats assessment for further use in the integrity management plan, • Optimize integrity aspects from a design, maintenance and operational point of view, • Investigate the influence of different design criteria for pipeline segments. To conclude, TIGF presents the benefits of the tool for their Integrity Management department and for planning inspection and for better knowledge of their gas transmission grid.

Improving the Integrity of Lap Joint Flange Connections

Bolted connections where proper alignment is critical usually require the use of lap joint flanges. The ability of lap joint flanges to swivel around the pipe enables the connection to be installed with no rotational stress applied to the attached piping and equipment. The majority of lap joint flanges on the Enbridge Pipelines system are ANSI 600 and are located at pump nozzles. In these applications, Enbridge Pipelines’ standard specifies the use of spiral wound gaskets with inner rings. Problems with lap joint flanges typically occur at the time of assembly. There are a number of factors that contribute to the challenges of properly seating a gasket in these joints: • Since the raised face is separate from the flange, there is some flex in the face that could unevenly load the gasket; • The flange may not be concentric with the raised face that is welded to the pipe because of clearance between the pipe OD and the flange ID. Using the bolt holes to align the flange does not necessarily ensure that the raised faces are aligned; • Line up pins are not recommended on pump nozzles in order to ensure that no stress is placed on the pump. Consequently, the bottom studs are used to center the gasket and it is possible for the gasket to sit in the stud threads, increasing the misalignment between the gasket windings and the flange raised faces; • Specified torque values for a given flange size may be too high for use in a lap joint application. The perfect bolt alignment in these joints may result in a lower nut factor and subsequently a higher bolt stress for a given torque value. All of these factors can cause damage to the windings on a spiral wound gasket, eventually resulting in a leak. This paper will discuss ways to mitigate these issues.

Study on Duration of Hydrostatic Leak Test for Gas Pipeline

A mathematical model about the duration of hydrostatic leak test for gas pipeline is developed for the first time in the paper. The influences of temperature variation, elastic deformation of the pipe and a certain amount of residual air filled within the pipe are synthetically considered in the model. The results indicate that the duration is longer while the amount of the residual air in the pipe or the volume of pipe is lager under the same pressure dropping. The required duration is increasing with the pressure going up. At the same time, the temperature variation greatly influences the pressure dropping of the pipeline. The conclusions are helpful for determining the reasonable duration of hydrostatic leak test for gas pipeline. Furthermore, it can also provide some references for judging leak test result while hot water pressure testing in winter.

A Comprehensive Distributed Pipeline Condition Monitoring System and Its Field Trial

In this paper we describe a unique and innovative pipeline and flowline monitoring system which has been developed by Schlumberger in collaboration with BP. Applications of the system include pipeline/flowline integrity monitoring and overall optimization of the operation of the pipeline/flowline. Details of the pipeline condition monitoring system (PCMS) components are provided along with the results from comprehensive field trials. The system uses novel optical fibre distributed sensors to provide simultaneous distributed measurements of temperature, strain and vibration for the detection, monitoring, and location of events including: • Third Party Interference (TPI), including multiple simultaneous disturbances; • Geo-hazards and landslides; • Gas and oil leaks; • Permafrost protection. The system performs analysis of the combination of measurands to provide the operator with an event recognition and location capability allowing the most appropriate early response to be initiated. Through the use of newly developed remote, optically powered amplification, an unprecedented detection range of 100km is achieved without the need for any electronics and therefore remote power in the field. A system can thus monitor 200km when configured to monitor 100km in two directions from a single location. As well as detecting the external conditions leading to leaks, this fully integrated system provides a means of detecting and locating small leaks in gas pipelines below the threshold of present online leak detection systems based on monitoring flow parameters. Other benefits include the enhancement of the operator’s existing integrity management program and the potential for reductions in surveillance costs and HSE risks. In addition to onshore pipeline systems this combination of functionality and range is available for practicable monitoring in a wide range of other applications such as: • Long subsea flowlines; • Umbilicals; • Power cables; • Offshore riser systems; • Settlement in tank farms; • Facilities perimeter security. An important deliverable from this work includes the design and field testing of a bespoke optical sensor cable, designed to be sensitive to ground movement to allow distributed strain measurement whilst withstanding the rigors of the pipeline environment. In this paper, we describe the new optical sensing methods developed, and the results of the extensive field trials performed during 2007 and 2008 to fully evaluate and prove the system for use on long hydrocarbon transmission pipelines. Specifically, we demonstrate the detection of small gas releases, simulated earth movement and a number of different types of third party interventions at the full 100km target range.

Uncertainty Evaluation of the Natural Gas Molar Mass and Its Flow Rate Impact

In Brazil, the National Oil Agency — ANP and the National Metrology Institute elaborated Regulation No 1, on June 19th 2000. This government decree approves the Regulation of the Measurement Technique of Oil and Natural Gas, which establishes the minimum conditions and requirements for the oil and natural gas measurement systems, in order to guarantee accurate and complete results. The natural gas measurement fiscal systems must be projected, calibrated and operated so that the measurement uncertainty does not exceed 1.5%. Based on the norms AGA and ISO, the mathematical model for the calculation of the mass flow rate, depends on quantities that have well known uncertainty such as: orifice plate diameter, pipeline internal diameter, compressibility factor, discharge coefficient, differential pressure, static pressure and flow temperature. However, for the molar mass standard uncertainty fixed values are utilized in Brazil (mainly by IPT and PUC-RJ), around 0.30%, independent of the natural gas composition. The objective of this work is to develop a methodology to calculate the molar mass uncertainty of the natural gas derived from its chemical composition, analyzed by gaseous chromatography and to comparing it with the value currently practiced, evaluating the impact proceeding from this difference in the mass flow rate of the natural gas. Based on this methodology, the molar mass uncertainty is around 0.05% and the fiscal system uncertainty decreases in more than 10% when it is compared with the mass molar fixed value uncertainty.