Designing Offshore Pipeline Systems Divided Into Sections of Different Design Pressures

2004 ◽  
Author(s):  
Gunnar Staurland ◽  
Morten Aamodt
Keyword(s):  
Uniform Design ◽  
External Pressure ◽  
Transportation Systems ◽  
Point Of View ◽  
Pipeline System ◽  
Operating Pressure ◽  
Pipeline Systems ◽  
Upstream Pressure ◽  
Transmission Pipeline ◽  
Design Pressure

Norwegian waters have been a main arena for development of subsea pipeline technology over the last 25 year. The gas transportation systems from Norway to continental Europe comprise the largest and longest sub sea pipelines in the world. Codes traditionally require a pipeline to be designed with a uniform design pressure between stations with overpressure protection capabilities. However, the downstream part of a very long gas transmission pipeline may, after commissioning, rarely, if ever, see pressures near the pressure at the upstream end. There is, therefore, a potential for cost reduction and capacity improvement if two, or several, sections of different design pressure could be used without having to implement sub sea pressure regulation and overpressure protection facilities at the point of transition between the different sections of design pressure. In determining the lower design pressure the shutdown of the pipeline outlet facilities, at any point in time allowing for a practicable, achievable delay for closure of the upstream inlet valve has to be taken into account. The settle out pressure in a “normal” shut-in situation shall then not exceed the lower design pressure. In addition, deep water pipelines are often designed to withstand buckling due to bending and external pressure during installation, and may therefore locally tolerate a much higher internal pressure than the pipeline was designed for. Transmission pipelines crossing deepwater areas may therefore be designed for two or more operating pressures along the pipeline, thereby optimizing the cost. Even more important, for already existing pipelines, the capacity may be significantly increased by utilizing the upstream heavy wall sections. The operating pressure range for a long offshore gas transmission pipeline is very wide compared to an onshore line, typically between an upstream pressure of 150–250 bar, and a downstream pressure of 60 to 80 bar over a distance of several hundred kilometers. It may take hours to notice the closure of a downstream valve on the upstream pressure. Unless the pipeline is extensively packed, it is obvious that the pressure drop along the pipeline may be taken into account by allowing a lower design pressure for downstream part than for the upstream part. Thereby, the investment cost can be reduced. This paper describes the principles of designing a pipeline system divided into sections of different design pressures from a hydraulic point of view. The basis is the offshore standard for designing submarine pipeline systems, DNV OS-F101. The focusing will be on improvements in transportation efficiency, cost reductions and operational issues.

scholarly journals Experimental and Numerical Vibration Analysis of Hydraulic Pipeline System under Multiexcitations

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Peixin Gao ◽  
Hongquan Qu ◽  
Yuanlin Zhang ◽  
Tao Yu ◽  
Jingyu Zhai
Keyword(s):  
Pressure Fluctuations ◽  
Fluid Motion ◽  
Fluid Pressure ◽  
Point Of View ◽  
Pipeline System ◽  
Base Excitation ◽  
Fem Method ◽  
Pipeline Systems ◽  
Pump Pressure ◽  
Improved Model

Pipeline systems in aircraft are subjected to both hydraulic pump pressure fluctuations and base excitation from the engine. This can cause fatigue failures due to excessive vibrations. Therefore, it is essential to investigate the vibration behavior of the pipeline system under multiexcitations. In this paper, experiments have been conducted to describe the hydraulic pipeline systems, in which fluid pressure excitation in pipeline is driven by the throttle valve, and the base excitation is produced by the shaker driven by a vibration controller. An improved model which includes fluid motion and base excitation is proposed. A numerical MOC-FEM approach which combined the coupling method of characteristics (MOC) and finite element method (FEM) is proposed to solve the equations. The results show that the current MOC-FEM method could predict the vibration characteristics of the pipeline with sufficient accuracy. Moreover, the pipeline under multiexcitations could produce an interesting beat phenomenon, and this dangerous phenomenon is investigated for its consequences from engineering point of view.

Designing Offshore Pipeline Safety Systems Utilising Flow and Pressure in Multi Design Pressure Pipeline Systems

2008 ◽  
Author(s):  
Gjertrud Elisabeth Hausken ◽  
Jo̸rn-Yngve Stokke ◽  
Steinar Berland
Keyword(s):  
Pressure Drop ◽  
Flow Measurement ◽  
Large Diameter ◽  
Pressure Sensors ◽  
Safety System ◽  
Pipeline System ◽  
Outlet Pressure ◽  
Pipeline Systems ◽  
Pipeline Safety ◽  
Design Pressure

The Norwegian Continental Shelf (NCS) has been a main arena for development of subsea pipeline technology over the last 25 years. The pipeline infrastructure in the North Sea is well developed and new field developments are often tied in to existing pipeline systems, /3/. Codes traditionally require a pipeline system to be designed with a uniform design pressure. However, due to the pressure drop when transporting gas in a very long pipeline, it is possible to operate multi design pressure systems. The pipeline integrity is ensured by limiting the inventory and local maximum allowable pressure in the pipeline using inlet and outlet pressure measurements in a Safety Instrumented System (SIS). Any blockage in the pipeline could represent a demand on the safety system. This concept was planned to be used in the new Gjo̸a development when connecting the 130 km long rich gas pipeline to the existing 450 km long FLAGS pipeline system. However, a risk assessment detected a new risk parameter; the formation of a hydrate and subsequent blockage of the pipeline. In theory, the hydrate could form in any part of the pipeline. Therefore, the pipeline outlet pressure could not be used in a Safety Instrumented System to control pipeline inventory. The export pressure at Gjo̸a would therefore be limited to FLAGS pipeline code. Available pressure drop over the Gjo̸a pipeline was hence limited and a large diameter was necessary. Various alternatives were investigated; using signals from neighbour installations, subsea remote operated valves, subsea pressure sensors and even a riser platform. These solutions gave high risk, reduced availability, high operating and/or capital expenses. A new idea of introducing flow measurement in the SIS was proposed. Hydraulic simulations showed that when the parameters of flow, temperature and pressure, all located at the offshore installation, were used; a downstream blockage could be detected early. This enabled the topside export pressure to be increased, and thereby reduced the pipeline diameter required. Flow measurement in Safety Instrumented Systems has not been used previously on the NCS. This paper describes the principles of designing a pipeline safety system including flow measurement with focus on the hydraulic simulations and designing the safety system. Emphasis will be put on improvements in transportation efficiency, cost reductions and operational issues.

Measuring the Effectiveness of Damage Prevention Techniques and Defining the Key Performance Indicators on Damage Prevention Efficiency

2012 ◽  
Author(s):  
Mark Piazza ◽  
Gina Greenslate ◽  
Nicolas Herchin ◽  
Laurent Bourgouin ◽  
Miriam Kuhn ◽  
...  
Keyword(s):  
Performance Indicators ◽  
Public Awareness ◽  
Prevention Programs ◽  
Key Performance Indicators ◽  
Pipeline System ◽  
Energy Transmission ◽  
Geographic Population ◽  
Pipeline Systems ◽  
Transmission Pipeline ◽  
Damage Prevention

Pipeline operators expend substantial efforts to develop, implement, and audit their Public Awareness and Pipeline Damage Prevention Programs. While the rate of pipeline damage incidents from third-party and outside force impacts has progressively declined over a period of several decades, these events remain a high priority for the pipeline industry and external stakeholders. There are multiple management and communications tools that are used to support Damage Prevention programs for energy transmission pipeline operations. These tools are applied to large pipeline systems that cross a range of geographic, population, and regulatory boundaries. These factors make it challenging to determine the effectiveness of the individual tools applied for damage prevention for energy transmission pipeline systems. This paper present the results of research performed through Pipeline Research Council International, Inc. (PRCI) to measure and quantify the effectiveness of the various damage prevention tools and techniques as they apply to energy transmission pipeline systems. The project focuses on data collection through a web-based platform to provide the basis to establish a set of Key Performance Indicators (KPIs) for assessing the effectiveness of the methods and techniques that are used as standard practices by most pipeline operators in their damage prevention programs. The research includes development of a consistent and systematic process and database for collecting information on damage and “near hit” incidents that are recorded by pipeline operators. Fault-tree analysis of these data is expected to show where improvements can be made (e.g., one-call center, ticket handling, operator response, contractor cooperation and diligence, locating and marking, monitoring). Improvements will be measured by PRCI by capturing and analyzing the data over a multi-year period. The key output of the project will be metrics that demonstrate which damage prevention activities are more effective in reducing impacts and “near hits” to pipelines and which activities positively contribute to the safe operations of the pipeline system.

scholarly journals A methodology for flexibility analysis of pipeline systems

2018 ◽  
Vol 233 (4) ◽  
pp. 893-907 ◽  
Author(s):  
Umer Zahid ◽  
Sohaib Z Khan ◽  
Muhammad A Khan ◽  
Hassan J Bukhari ◽  
Salman Nisar ◽  
...  
Keyword(s):  
Transportation Systems ◽  
Pipeline System ◽  
Time Saving ◽  
Transport Efficiency ◽  
Flexibility Analysis ◽  
Long Span ◽  
Economic Significance ◽  
Pipeline Systems ◽  
Pipeline Design ◽  
Selection Of

Pipeline systems serve a crucial role in an effective transport of fluids to the designated location for medium to long span of distances. Owing to its paramount economic significance, pipeline design field have undergone extensive development over the past few years for enhancing the optimization and transport efficiency. This research paper attempts to propose a methodology for flexibility analysis of pipeline systems through employing contemporary computational tools and practices. A methodical procedure is developed, which involves modeling of the selected pipeline system in CAESAR II followed by the insertion of pipe supports and restraints. The specific location and selection of the inserted supports is based on the results derived from the displacement, stress, reaction, and nozzle analysis of the concerned pipeline system. Emphasis is laid on the compliance of the design features to the leading code of pipeline transportation systems for liquid and slurries, ASME B31.4. The discussed procedure and approach can be successfully adjusted for the analysis of various other types of pipeline system configuration. In addition to the provision of systematic flow in analysis, the method also improves efficient time-saving practices in the pipeline stress analysis.

scholarly journals Optimization of the Gas Transport in Pipeline Systems

2016 ◽  
Vol 66 (1) ◽  
pp. 103-120 ◽  
Author(s):  
Anton Sedliak ◽  
Tibor Žáčik
Keyword(s):  
Gas Transport ◽  
Optimization Problems ◽  
Software Implementation ◽  
Evolution Strategies ◽  
Pipeline System ◽  
The Real ◽  
Pipeline Systems ◽  
Transmission Pipeline

Abstract The purpose of this work is to design a suitable methodology to solve selected optimization tasks from the field of gas transport in pipeline systems. The modifications of evolution strategies algorithm to solve such optimization problems was developed. Testing of algorithm has been realized by a software implementation on the model of the real transmission pipeline system.

Gas Transmission Pipeline Safety and Integrity Activities and Results for INGAA Pipeline Companies

2012 ◽  
Author(s):  
Terry Boss ◽  
J. Kevin Wison ◽  
Charlie Childs ◽  
Bernie Selig
Keyword(s):  
Natural Gas ◽  
Management Practices ◽  
Pipeline System ◽  
Mandated Reporting ◽  
Pipeline Systems ◽  
Natural Gas Transmission ◽  
Transmission Pipeline ◽  
Integrity Management ◽  
Pipeline Safety ◽  
Transmission Pipelines

Interstate natural gas transmission pipelines have performed some standardized integrity management processes since the inception of ASME B3.18 in 1942. These standardized practices have been always preceded by new technology and individual company efforts to improve processes. These standardized practices have improved through the decades through newer consensus standard editions and the adoption of pipeline safety regulations (49 CFR Part 192). The Pipeline Safety Improvement Act which added to the list of these improved practices was passed at the end of 2002 and has been recently reaffirmed in January of 2012. The law applies to natural gas transmission pipeline companies and mandates additional practices that the pipeline operators must conduct to ensure the safety and integrity of natural gas pipelines with specific safety programs. Central to the 2002 Act is the requirement that pipeline operators implement an Integrity Management Program (IMP), which among other things requires operators to identify so-called High Consequence Areas (HCAs) on their systems, conduct risk analyses of these areas, and perform baseline integrity assessments and reassessments of each HCA, according to a prescribed schedule and using prescribed methods. The 2002 Act formalized, expanded and standardized the Integrity Management (IM) practices that individual operators had been conducting on their pipeline systems. The recently passed 2012 Pipeline Safety Act has expanded this effort to include measures to improve the integrity of the total transmission pipeline system. In December 2010, INGAA launched a voluntary initiative to enhance pipeline safety and communicate the results to stakeholders. The efforts are focused on analyzing data that measures the effectiveness of safety and integrity practices, detects successful practices, identifies opportunities for improvement, and further focuses our safety performance by developing an even more effective integrity management process. During 2011, a group chartered under the Integrity Management Continuous Improvement initiative(IMCI) identified information that may be useful in understanding the safety progress of the INGAA membership as they implemented their programs that were composed of the traditional safety practices under DOT Part 192, the PHMSA IMP regulations that were codified in 2004 and the individual operator voluntary programs. The paper provides a snapshot, above and beyond the typical PHMSA mandated reporting, of the results from the data collected and analyzed from this integrity management activity on 185,000 miles of natural gas transmission pipelines operated by interstate natural gas transmission pipelines. Natural gas transmission pipeline companies have made significant strides to improve their systems and the integrity and safety of their pipelines in and beyond HCAs. Our findings indicate that over the course of the data gathering period, pipeline operators’ efforts are shown to be effective and are resulting in improved pipeline integrity. Since the inception of the IMP and the expanded voluntary IM programs, the probability of leaks in the interstate natural gas transmission pipeline system continues on a downward slope, and the number of critical repairs being made to pipe segments that are being reassessed under integrity programs, both mandated and voluntary, are decreasing dramatically. Even with this progress, INGAA members committed in 2011 to embarking on a multi-year effort to expand the width and depth of integrity management practices on the interstate natural gas transmission pipeline systems. A key component of that extensive effort is to design metrics to measure the effectiveness to achieve the goals of that program. As such, this report documents the performance baseline before the implementation of the future program.

scholarly journals Specificity of the development and characteristics of mixed damage to network structures of pipeline transportation systems

Dependability ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 4-11
Author(s):  
I. A. Tararychkin
Keyword(s):  
Emergency Situation ◽  
Random Order ◽  
Transportation Systems ◽  
Pipeline System ◽  
Progressive Damage ◽  
Network Structures ◽  
Pipeline Transportation ◽  
Pipeline Systems ◽  
Linear Elements ◽  
Correct Comparison

Pipeline transportation systems are used in various industries for the purpose of delivering various substances and materials to consumers. If, as the result of an accident development, a certain number of random linear elements (pipelines) consecutively fail, such scenario of events is called progressive damage. If several pipelines converging at a node fail simultaneously, such point element of the system is blocked. Progressive blocking of a certain set of nodes of a pipeline system in random order is called a progressive blocking. Simultaneous development within a system of progressive damage to linear elements and blocking of transportation nodes represents mixed damage. Mixed damage is a hazardous form of emergency, and its development causes fast degradation of a system’s transportation capabilities.The Aim of the paper is to study the characteristic properties and patterns of the progress of mixed damage affecting network structures of pipeline systems, as well as evaluating such systems’ capability to resist its development.Methods of research. The characteristics of network entities’ resilience to the development of mixed damage were identified by means of computer simulation. The nature of the effects to which a system is exposed was defined with a cyclogram, whose integer parameters indicate the alternation of the process of sequential damage of linear elements and nodes of a network structure.Results. It has been established that a correct comparison of the resilience of various network structures to mixed damage is only possible with regard to comparable facilities. For that purpose, the analyzed systems must have identical numbers of nodes, linear elements and end product consumers. Additionally, such systems must be exposed to effects with identical cyclograms. It is shown that the correlation of the resilience of comparable network structures does not depend on the specific type of mixed damage cyclogram, but is defined by the nature of the connections within a particular system.Conclusions. Mixed damage is a hazardous development scenario of an emergency situation that is associated with rapid degradation of the transportation capacity of pipeline systems. The ability of network structures of pipeline systems to resist mixed damage is evaluated based on indicators that are defined by means of simulation. A correct comparison of the resilience of various structures to mixed damage is only possible in case they are comparable. For that purpose, they must have identical numbers of nodes, linear elements and product consumers. Additionally, such systems must be exposed to damage procedures with identical cyclograms. The correlation of the resilience of network structures that comply with the comparability conditions does not depend on the adopted damage cyclogram, but is defined by the existing set of connections within a particular system.

A Systematic Approach for Evaluating Dent Severity in a Liquid Transmission Pipeline System

2010 ◽  
Author(s):  
Chris Alexander ◽  
Eelco Jorritsma
Keyword(s):  
Systematic Approach ◽  
Element Model ◽  
Fatigue Curve ◽  
Pipeline System ◽  
Operating Pressure ◽  
Remaining Life ◽  
Recent Experimental Study ◽  
Analysis Methodology ◽  
Transmission Pipeline ◽  
Level 3

An API 579 Level 3 assessment was performed to determine the stresses in a 2% dent in a 20-inch × 0.406-inch pipeline. The intent was to determine the stress concentration factor (SCF) in the dent with a finite element model using geometry data provided from an in-line inspection caliper run. In addition to the analytically-derived SCF, data were also evaluated from a recent experimental study involving a plain dent subjected to cyclic pressure conditions with a profile comparable to the dent in question. This sample was cycled at a stress range of 70% SMYS and failed after 10,163 cycles had been applied. Using the DOE-B mean fatigue curve, combined with the experimental fatigue life, the resulting SCF factor was derived to be 4.20. This value is within 1% of the calculated FEA-based SCF and served to confirm the technical validity of the SCF. The operator provided historical pressure data covering a 12-month period and a rainflow count analysis was performed on the data. Using this data, along with the API X′ design fatigue curve, the estimated remaining life was determined for the dent in question and conservatively estimated to be 65 years. This paper provides details on the analysis methodology and associated results, discussions on the empirically-derived SCF with its use in validating the analytical SCF, and application of the results to estimate the remaining life of the pipeline system. It is the intent of the authors to provide the pipeline industry with a systemic approach for evaluating dent severity using caliper and operating pressure history data.

Use of Spoolable Pipe Technologies As a Means for Rehabilitating Small Diameter High Pressure Pipeline Systems

2020 ◽  
Author(s):  
Chantz Denowh ◽  
Chris Alexander ◽  
Frank Cox ◽  
Richard Kania
Keyword(s):  
Small Diameter ◽  
Full Scale ◽  
Combined Loading ◽  
Pipeline System ◽  
Central Feature ◽  
Repair System ◽  
Operating Pressure ◽  
Full Scale Test ◽  
Pipeline Systems ◽  
Scale Test

Abstract The aging infrastructure of pipeline systems around the world requires operators to explore novel and innovative methods for rehabilitating pipelines. Conventional repair methods involve the installation of steel sleeves or composite repair systems. While these repair methods are reliable and provide operators with options for pipeline repair, a major drawback is the requirement that pipelines must be excavated. Activities related to excavation have inherent risk in the form of personnel and environment safety along with the applicable cost of excavation activities. If extensive flaws are present in a pipeline system, efforts associated with a comprehensive pipeline repair system can be cost-prohibitive. Additionally, the rehabilitation of pipelines that were installed via horizontal direction drilling, using current repair methods, is near to impossible. This paper provides an in-depth presentation on a comprehensive study completed to evaluate the use of a spoolable pipeline technology as a means for rehabilitating pipelines. Results are included from an industry survey with responses from 15 pipeline operators on the use of spoolable pipe technologies. One outcome from the survey was the lack of full-scale test data associated with combined loading, which was a central feature in the current study. The combined loads considered in the year-long study included burst testing and cyclic pressure testing utilizing torsion, axial tension, and axial compression loads. More than 30 full-scale test samples were destructively tested in combined loading scenarios, utilizing up to 100,000 pressure cycles to the full operating pressure of the pipeline system. The approach employed in this study, and the associated test results, provides a model for evaluating a spoolable pipeline technology prior to implementation for rehabilitating pipelines. This approach is in addition to the required product qualification standards accepted by industry.

New Frontienrs in Pipeline Pressure Isolation: Non-Invasive, Without De-Pressurizing, Production Loss or Flow Interruption

2008 ◽  
Author(s):  
Rush Selden ◽  
Mark Sim
Keyword(s):  
High Pressure ◽  
New Technologies ◽  
External Pressure ◽  
Pipeline System ◽  
Thin Wall ◽  
Operating Pressure ◽  
Repair Work ◽  
Flow Interruption ◽  
Fail Safe ◽  
Spiral Wound

There are several methods for pressure isolating pipelines. Along with hot tapping and stopple and freeze plugging, there is another common method known as remote controlled (tether-less) pipeline plugging, whose use is increasing — both offshore and onshore. This paper will review piggable tether-less plugging technology, provided by TDW Offshore Services using the SmartPlug™, and case histories whereby a bi-directionally piggable, remotely actuated (tether-less) plug is deployed to allow pipeline operators to perform repair work, modifications, or tie-ins on pipeline systems without interrupting production in the remaining part of the pipeline system, i.e., while operating live and at production pressure. Specifically this paper will address two new technologies: First, allowing high pressure isolation of thin wall pipe, and second, of spiral wound pipe, both without welding, tapping or leaving any trace of the fact that an isolation occurred. Some advantages of tether-less plugging technology are: • Plugging tools have higher pressure containment capacity than other plugging methods, typically up to 3,000 psi. • Bi-directionally piggable, able to negotiate as small as 1.5D bends, operated and monitored entirely via remote control (tether-less through-wall control and communication system). • Compared to hot tapping, welding a fitting on the pipeline is not required, and no need to hot tap (drill) into the pipeline, no future leak path and no issues regarding cuttings or coupon. This latest frontier of pressure isolation allows for plugging tools that are fail-safe (the higher the differential pressure the harder they set) with zero leakage tolerance. They can be configured for job specific requirements such as double or single block, and can allow for hydrotesting the completed work. The most important advantage is that they eliminate the time needed and lost production cost of displacing pipeline product, flaring, depressurizing, emptying the line, and re-commissioning the line. In addition, specifically this paper will address the latest technology advances allowing high pressure isolation of thin wall (8mm/0.32 inch) spiral wound pipe using external pressure reinforcement clamps over the pressure isolation tool during an onshore project on a 24″ methane gas pipeline. During the isolation, a portion of the upstream pipeline was removed and replaced while the entire pipeline downstream of the pressure isolation remained under full operating pressure, thus requiring no loss of production from downstream assets during the repair. Once complete the tools were released and pigged from the line, leaving no holes, no welds, no future leak path and no trace that any event occurred on the pipeline in that location.

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