Analyzing the Effectiveness of Prevention Measures for Third-Party Damage to Underground Pipelines Using a Hierarchical Fault Tree Model

This paper presents a hierarchical fault tree model for analyzing the effectiveness of measures for the prevention of third-party mechanical damage to underground pipelines. The model consists of a high level failure model that provides an overall indication of the effectiveness of a damage prevention program; and lower level fault tree models that detail the effectiveness of individual damage prevention measures. The model developed in this paper is consistent with current damage prevention and data collection practices, and it presents information in a simple and intuitive format that facilitates analysis and interpretation. The hierarchical fault tree approach developed in this paper is shown to be a useful tool for evaluating the effectiveness of various measures to prevent third-party damage and for identifying weak links in current damage management practices. It can also serve to inform the development of new damage prevention techniques and to identify information priorities relevant for future data collection and interpretation efforts aimed at reducing the frequency of third-party damage events.

Alternative Compressive Strain Capacity Performance Limits for Strain Based Design Applications

Existing industry standards have established the compressive strain capacity of pipelines within an empirical basis. The compressive strain capacity is generally associated with the peak moment. This approach has evolved from elastic stability concepts used in structural engineering for unrestrained pipe segments subject to primary loading (i.e. force or load control) conditions. This limiting condition does not take advantage of the observed performance for buried pipelines, when subjected to displacement control events such as differential ground movement, where the pipe curvature can exceed the peak moment response without loss of pressure containment integrity. This inherent conservatism may have a negative impact on project economics or sanction where the compressive strain capacity, rather than tensile rupture limits, governs the strain based design methodology. For these conditions, alternative performance limits defining the pipe compressive strain capacity are required. A numerical study was conducted, using finite element methods, to examine possible alternative compressive strain criteria for use in strain-based design applications. The results from this study and the requirements to bring these concepts forward through integration with industry recommended practice are presented.

Long Term Structural Integrity Considerations for Abandoned Pipelines

There has been increasing interest across the industry to better understand the possible long term risks associated with out of service pipelines. In Canada, the Canadian Energy Pipeline Association (CEPA), Petroleum Technology Alliance of Canada (PTAC), and the National Energy Board (NEB), have undertaken multiple studies to identify and assess the threats related to pipeline abandonment. [1][2][3] The primary hazards typically identified across industry for pipeline abandonment are associated with long term corrosion degradation, potential for creation of water conduits, possible environmental impacts, and potential for pipeline collapse and associated soil subsidence. Unfortunately, little guidance is presently available to the industry for determining remaining structural capacity of a heavily corroded pipeline to establish likelihood, and possible timeline, of collapse, nor for determining possible subsidence magnitudes associated with large diameter transmission lines. This paper presents a technical case study for an assessment approximating the remaining strength of an abandoned pipeline subject to long term corrosion degradation, considering both general metal loss, and randomized pitting and perforation growth. The work presented used a combination of finite element analyses, and existing industry models for determining load bearing capacity of an abandoned pipeline under varying levels of degradation.

Assessment of Stress-Displacement State of Cable Suspended Pipeline Bridge During Inspection Pig Motion

Designing and maintenance of pipeline cable bridge with dynamic loads is complex because this problem belongs to the geometrically nonlinear problems. Analysis shown that existing mathematics models of cables have restrictions in use and we can’t use these cable models for dynamic loads calculations of cable-suspended pipeline bridge. Movement, produced by motion of inspection pig inside pipeline is an example of such dynamic loads. During its motion through the pipeline cable bridge the inspection pig induces additional stresses in pipeline due its weight and finite velocity which induces the vibration of the bridge. Its stress state assessment requires a lot of modeling, measuring and calculating actions to be done. First of all the initial static stress state of the cable bridge should be evaluated. It depends on the existing tension forces in the cable elements. They approximately were derived from the optical measurement of their geometrical curvatures with accounting for known weight density of the cables. Then, existing software tool for piping stress calculation “3D Pipe Master”, which operates by 12 degrees of freedom in pipe elements, was modernized to be able to take into account the geometrically nonlinear behavior of 6 d.o.f. cable elements. The equations which relate the elongations and rotations of cable elements with tension forces in cables are written in the form convenient for application of the transfer matrix method in the linearized iteration procedure which adjusts the measured displacements of the elements of the bridge with calculated one. In this way the initial tension forces in cables, in particular, and the bridge state, in general were determined. The dynamic part of the problem is solved by expansion in terms of natural frequencies eigenfunctions. Given inspection pig velocity calculation allows to determine the time dependence of generalized loads for each of natural vibration mode as product of the pig weight multiplied by mode shape displacement in point of pig position at the given time moment. Eventually the technique of Duhamel integral is used to calculate the dynamic behavior of the bridge for each natural mode of vibration. Two examples of dynamic stress calculation are considered. First is primitive one and relate to calculation joint interaction pipeline and cable system at dynamic loading. The second example concerns dynamic calculation pipeline cable bridge through the river Svicha during movement inspection pig. This bridge consists of two support, two parallel pipelines (1220×15) with bends and cable system. Analysis shown possibility uses “3D Pipe Master” software for the solving problems of durability pipeline cable bridge any complexity in the conditions of static and dynamic loading.

‘We’re Still Hitting Things’: The Effectiveness of Third Party Processes for Pipeline Strike Prevention

High-pressure gas pipelines are vulnerable to damage in the course of building or maintaining other infrastructure, such as roads, water pipelines, electricity or telecommunications cabling. Unlike other countries, there has never been a death or serious injury from a high-pressure gas pipeline strike in Australia and yet external interference continues to be the most common cause of pipeline damage despite a range of technical and legislative measures in place. This research project aims to enhance the safety strategies regarding third party pipeline strikes by giving the pipeline sector a greater understanding of the motivations and priorities of those who work around pipeline assets and so how to work with them to achieve better outcomes. Using data gathered from more than 70 in-depth interviews, we explore empirically alternate understandings of risk amongst a range of stakeholders and individuals that are responsible in some way for work near or around high-pressure gas transmission pipelines in Australia. Outside the pipeline sector, much of the work around pipelines is conducted by those at the bottom of long chains of contractors and sub-contractors. We discuss perceptions of risk held by a range of third party actors whose activities have the potential to threaten gas pipeline integrity. We compare these views with gas pipeline industry perceptions of risk, couched in terms of asset management, public safety, legal and insurance obligations, and reputation management. This paper focuses on how financial risk and so also management of the potential for pipeline strikes is shifted down the third party contractor chain. Added to this, incentives for timely project completion can unintentionally lead to situations where the potential for third party contractors to strike pipelines increases. The data shows that third party contractors feel the time and cost impact of design or project changes most immediately. Consequently, strikes or near misses may result as sub-contractors seek to avoid perceived ‘unnecessary’ time delays along with the associated financial impact. We argue that efforts to reduce the potential for pipeline strike need to be targeted at structural changes, rather than simply aimed at worker risk perception and enforcement of safety compliance strategies.

Standardization of SENT (or SE(T)) Fracture Toughness Measurement: Results of a Round Robin on a Draft Test Procedure

Fracture toughness of steels is conventionally measured using bend specimens and provides a conservative estimate of toughness when the actual loading is in tension. There has been widespread interest in characterizing the toughness that occurs with reduced constraint to better reflect constraint conditions typical of a relatively shallow girth weld flaw. There is currently a standardized approach to measure fracture toughness in tension loaded specimens, however, it requires testing of multiple specimens to generate a resistance curve. Recent developments in fracture toughness testing and analysis of tension loaded specimens have led to publications by CANMET and Exxon Mobil Upstream Research Company toward development of a single-specimen procedure. As part of an initiative to enhance the state of the art in strain based design and assessment methods, with the intent of providing support for the standardization of appropriate weld testing methods, BMT under a Pipeline research Council International (PRCI) project has combined the two single-specimen approaches and developed a recommended practice for fracture toughness testing using single-edge-notched tension SENT (or SE(T)) samples with fixed grip loading. The procedure has been assessed by means of a round robin test program involving laboratories from around the world. Girth welds were fabricated and base metal, heat affected zone and weld center line specimens were prepared and sent to round robin participants. For the round robin program all the participants used a double clip gauge arrangement for direct CTOD measurement and electric potential drop measurement or unloading compliance method for crack growth measurement. In this paper, the results of the round robin test program including comparison of J and CTOD resistance curves will be presented and discussed.

The Advantages of Integrating Major Hazard Safety and Impact Assessments for Pipeline Projects

During many years of working on oil and gas pipeline projects, the authors have experienced many occasions where safety and environmental professionals on the same project have conducted assessments without using an integrated approach, often to the detriment of the project. This ‘siloed’ behaviour is evident in the way that safety and environmental teams are often assembled at different times and have little to no interaction. An Environmental, Social and Health Impact Assessment (ESHIA) is used as a key mechanism to identify potential adverse consequences from a pipeline project in terms of unwanted impacts to fauna and flora and local communities. Simultaneously, major hazard studies are carried out for a pipeline project to identify major accident hazards risks to adjacent communities or at above ground installations (AGIs), usually from flammable events due to the transport of natural gas, crude oil or petroleum products. Both the ESHIA and the major accident hazards processes will identify appropriate prevention, control and mitigation measures to reduce the risk from the pipeline system and to manage the potential adverse consequences in the unlikely event of a major accident. Within the scope of many ESHIAs prepared now, there is an assessment of environmental and social impacts from ‘unplanned events’, which essentially are those major hazard events with the potential to cause multiple injuries or fatalities to people in the local community or at AGIs. As such events are likely to have a major consequence to the environment, particularly in the case of crude oil and petroleum products releases, it makes sense for such events to be studied by both safety and environmental professionals using an integrated approach. Such an integrated approach requires collaboration between various professionals from an early point within a project, as there are several different aspects with a pipeline project that will require the assessment of key personnel. For a pipeline project in the design stages, the main points for consideration are as follows: • Construction of the pipeline system, with major disruptions to the local environment from the construction itself (line pipe and AGIs) and due to the logistical requirements (traffic movements, movements of personnel and construction camps, moving major equipment across the world). • Operation of the pipeline system, with potential adverse impacts due to a loss of containment, as has been shown by many accidents in the past (e.g. Ref 1, 2). The key issue here is that the initiating events often remain the same, certainly with regard to operations where the initiating event will be a loss of containment. There may be adverse consequences to people, the biological environment and the physical environment, depending on the location and nature of the incident. For this reason joint participation in the hazard identification (HAZID) process by key safety, social and environmental professionals is considered beneficial to a pipeline project to ensure all potential initiators are included. In this case, the HAZID process would also include an environmental impact identification (ENVID), rather than conducting both processes separately. A major advantage of conducting an integrated approach is the potential cost-savings. By bringing together technical safety and environmental professionals at an early stage of pipeline project design, there is the potential to avoid ‘doubling-up’ on potential issues, as well as conducting two parallel processes that have many similarities. Perhaps more significantly, many potential adverse consequences (environmental, social and safety) can be prevented, controlled or mitigated through their early consideration during project design. Hence, by bringing together these different technical view-points at an early stage of pipeline system design, potential risk reduction options that would be beneficial to people and the environment may be identified. If ESHIA considerations and major accident hazard studies are evaluated in parallel during the early stages of a project (e.g. Appraise or Select), a pipeline project will have more available options to prevent potential impacts. As prevention of hazards is generally more cost-effective than designing in control and mitigation measures (for recovery of an incident), this will have a critical financial benefit. Furthermore, early changes to project design are generally far less costly than changes in the latter stages of a pipeline project; hence, early identification of prevention and risk reduction may be hugely beneficial.

Unlocking the Power of Incident Investigation: Building a Strong Pipeline Safety Management System From a Solid Foundation

As many pipeline operators embark on the journey of developing a Pipeline Safety Management System (PSMS), the first question is typically, “Where do we begin?” Management systems can be intimidating, and the thought of taking on the task of developing one can seem overwhelming. Companies want to know if it is necessary to start from scratch, if they can use existing processes or programs, and which step to take first for a successful PSMS. There are many ways to begin, but one of the most effective ways is to first ask two questions, “What do we already have?” and “What are our biggest problems?” Armed with these answers, a path forward can be developed, and the foundation for the management system can begin to take shape. One effective way to choose where to begin when developing the PSMS is to determine which elements have been related to the root causes of incidents and near misses in the past. Likewise, continuing to determine and monitor the causes of incidents after the implementation of the PSMS will provide guidance for continual improvement of the management system. Using the elements and sub-elements of existing management system standards or practices, such as API RP 1173, Pipeline Safety Management System Requirements [1], as a starting point for determining root causes is a good way to break down, categorize, and trend the causes of each incident. Combining these with a gap analysis of both the undocumented and documented processes and procedures will provide a basis for determining the priorities for development and implementation of each management system element.

Risk Based Strategy for the Development of an Emergency Pipeline Repair System (EPRS)

This paper presents an overview of the various components of an emergency pipeline repair system which should be in place in order to act effectively and efficiently during an emergency pipeline repair scenario. The condition of pipelines during operation is typically monitored by means of external and internal inspections. These inspections allow for planned intervention when a pipeline is found to be deteriorating. A failure to inspect adequately for time dependent threats, or randomly occurring events such as third party interaction, could result in a pipeline failure, leading to a requirement to rapidly return to operation and thus the need for an emergency repair. An Emergency Pipeline Repair System (EPRS) is therefore an essential part of a pipeline integrity management system. The primary purpose of the EPRS is to ensure that pipeline operators have the necessary level of readiness to allow an emergency repair to be carried out, thus minimising the economic consequences of having a pipeline out of service, whilst optimising the cost of purchasing and maintaining equipment and spares. In general, pipeline operators will have some emergency repair procedures to cater for unplanned or unexpected incidents. However, to complete an emergency repair efficiently and effectively, the availability of adequate spare materials and timely access to the damage location is required. For a large pipeline network, satisfying these requirements can be challenging. This paper discusses some basic elements of an EPRS and describes a case study of the development of a risk based EPRS strategy for an offshore pipeline operator. This approach involves the identification of credible hazards that can lead to damage requiring an emergency repair, and identification of repair options. The relative importance of the individual pipelines, in terms of their availability requirement, and the expected time required to complete an emergency repair are then taken into account. This enables the pipelines to be ranked based on the consequence of failure. Pipelines with consequence rankings that are considered unacceptable are therefore highlighted, and EPRS readiness related to those pipelines can subsequently be optimised. Recommendations for the development of an EPRS for an onshore or offshore pipeline network are also made.

Pipeline Project Technical Documents Control and Compliance

This paper presents an overview of Pipeline Project Technical Documents, along with Control Room Management and Compliance Issues, Challenges and Processes in the Oil & Gas Industry. It will be based on the work that the authors have developed between 2010 and 2015. With an overwhelming number of standards, norms, and best practices, operational and security requirements needs to be well implemented and documented. Any compliance issues have the potential to cause serious repercussions to an organization as an incident or an audit failure could result in significant financial loss. This review is especially critical to the industry as it highlights the advantages of taking a broad approach to obtain and maintain compliance in today’s Oil & Gas regulatory environment. The focus will be on pipeline monitoring regulations - Department of Transportation (DOT) - Pipeline and Hazardous Materials Safety Administration (PHMSA) and American Petroleum Institute (API) recommended practices: API 1164 (Supervisory Control and Data Acquisition System - SCADA Security), API 1165 (SCADA Displays), API 1167 (SCADA Alarm Management) and API 1168 (Control Room Management). Regarding Supervisory Control and Data Acquisition Systems (SCADA) security, this includes not only IT infrastructure such as computers and network related appliances, but also other equipment such as programmable logic controllers (PLCs) and Remote Terminal Units (RTUs) depending on the system architecture. The cyber-security threat has become a real issue related to critical infrastructure protection, and physical or human-risk issues. Understanding the systems vulnerabilities that could impact the availability of the control system and the facilities it controls is key. On the Control Room Management side, current PHMSA regulatory framework, a human factors plan is required to ensure control systems match human capabilities and limitations. Pipeline operators are since required to inform controllers of their roles and responsibilities, and carefully assess the implications on each of the following SCADA areas: alarm management, documentation and procedures, HMI displays, shift handover, fatigue management, change management and training. Therefore with the pipeline industry facing increasing regulatory scrutiny and ever-increasing cyber-threats, it’s more important than ever for companies to improve their plans, documentation, and processes. Companies around the globe are converging and prioritizing Security and Control, establishing long-term strategy to meet and sustain regulatory compliance to remain competitive, increase efficiency and productivity. The authors, working jointly with the client and industry leaders, have developed compliance methods and procedures to deal with these challenges. After applying these methods and procedures, the observed results were translated into smoother transitions to a centralized SCADA control center, which not only meet regulatory safety guidelines and PHMSA regulation, but also added value and efficiency to the control center operations.