Identifying Minimum Safe Distance between Adjacent Parallel Pipelines

To meet the increasing energy demand, oil and gas pipelines from Myanmar to China have been planned since 2003. After 10 years’ hard work, Myanmar-China Oil and Gas Pipeline Project had been completed by the end of 2013. The project comprises one gas pipeline and one oil pipeline. The gas pipeline with a diameter of 1016 mm and a total length of 1727 km runs through great mountain areas in the southwest of China. The oil pipeline with a diameter of 813 mm and the first phase length of 606 km is laid parallel to the gas pipeline. The challenges of this project are long distant parallel large pipelines, undulant topography with high different elevation, complicated geological condition, vulnerable ecology, etc. This paper presents some design and construction issues concerned in the project, including the route selection in mountain areas, type of crossings and its design, type of ground movements and its design, special construction methods in these areas, etc. New technologies such as GIS-based route optimization, strain-based design, longspan suspension bridges, tunnels through mountains, multiple pipelines laid in narrow or steep areas and monitoring system for seismic and fault movement had been applied to conquer the challenges.

Personal safety and environmental issues, such as fires and explosions, have climbed to the top of the list of concerns due to the rupture of a high-pressure gas pipeline. Analysis of the diffusion characteristics of methane leaks in soil and air is essential for engineering maintenance and the prevention of secondary mishaps. The primary contribution of this paper is the design and establishment of a full-scale experimental system to simulate small-hole leakage of high-pressure gas pipeline in order to observe the leakage and diffusion behavior of methane in soil and atmosphere under various leakage pore sizes and pressures. The results show that, near the leakage hole, the high-pressure jet dominates the action, whereas near the surface, lateral diffusion and accumulation dominate for an extended period of time. When the diffusion reaches a stable state, the vertical and horizontal diffusion distances are 0.76 m and 1.05 m, respectively, and the maximum temperature difference at the leakage hole is 8.7°C; Under the conditions of leakage holes of 0.5 mm, 1.0 mm, and 1.5 mm, the surface leakage radii are 0.4 m, 0.8 m, and 1.4 m, respectively. The leakage aperture is the main factor affecting the diffusion of methane in soil; A small hole leakage rate model for high-pressure gas pipelines was established based on experimental data, with an average error of 9%; The response time and steady time in the process of methane concentration growth have an exponential relationship with horizontal distance from the leakage hole and a power function relationship with vertical distance and leakage rate. The average relative errors of the calculation formula are 16% and 12%, respectively. This work can provide a basis for the hazard assessment of small hole leakage and diffusion in buried gas pipelines, and also provide data support for the theoretical and numerical models of high-pressure gas flow in soil and atmosphere.

External corrosion of oil and gas pipelines: A review of failure mechanisms and predictive preventions

Long-distance oil and gas pipelines cross complicated terrain that different section of the pipeline suffers from different seismic excitation. If a consistent ground motion input is employed to the dynamic response analysis, there will be a big difference with the actual situation. In this paper, multi-support seismic input is considered to make dynamic analysis of long-distance oil and gas pipeline, time history method is used to compare and analyze the dynamic response of a typical long-distance gas and oil pipeline with multi-support and single-support seismic excitation. The dynamic response calculating result tells that these two kinds of seismic input methods have big differences. Therefore, the effect of multi-support seismic excitation should be considered when doing earthquake response analysis of pipes.

The pipelines are one of most important section of the fuel and energy complex of Russia. About 75% of them are presented by gas pipelines of large diameter (1020–1420 mm) for the operating pressure up to 7.4 MPa. CNIIchermet after I.P. Bardin put a big contribution into creation of pipe steels and mastering of technologies for their production at steel-works of Russia. The Institute in cooperation with leading steels-works developed an array of pipe steel, which are successfully used at construction of modern gas and oil pipelines. Tendencies of requirements increasing to characteristics of steels for large diameter pipes for pipelines considered, creation stages of grade range of steels and technology of rolled products production analyzed. Main technological requirements for achieving mechanical properties high level determined. It was shown, that K60–K65 strength class steels meet requirements to northern pipelines for a pressure up to 11.8 MPa, to thick walled underwater pipelines for a pressure of 25.0 MPa and to pipes for seismic arears. Steel-works and pipe-manufacturing plant of Russia provide the production of longitudinal-welded pipes with wall thickness up to 40–60 mm with anticorrosion external coating and smooth internal coating.

Fire Risk Study of Long-distance Oil and Gas Pipeline Based on QRA

Enbridge’s decision to formalize a Process Hazard Analysis (PHA) program has taken the organization through a journey from an informal/ad hoc practice to a rigorous, standardized, best-practice-based process with selected methodologies and tools being applied to all capital and operation projects in the company. This paper begins with a description of past hazard practices in the oil and gas pipeline industry in relation to the application of a hazard analysis. The oil and gas pipeline industry is governed by PHMSA, NEB, TSB, and provincial OHSA regulations, but is not regulated by OSHA or EPA RMP. Using this regulatory framework as a reference, a standard corporate PHA at Enbridge was developed and implemented. The paper describes the process, the methodologies, and the associated templates and tools. The implementation strategy is also discussed, including training deployment and communication plans. Finally, a road map for continuous improvement describes how to make the process sustainable by closing the current process gaps in relation to best practices and achieving a maturity stage of execution.

The article analyzes the theoretical, legal and applied problems of qualification of theft from an oil pipeline, gas pipeline, oil product pipeline by means of unauthorized tie-ins into main or production oil product pipelines and examines the features of the criminal-legal assessment of their careless damage. The high social danger of these crimes and significant material damage are noted. The results of the study allow us to reveal some contradictions in the application of measures of criminal responsibility for the same unlawful acts committed under identical circumstances.

Experimental study on dynamics of rotatable bypass-valve in speed control pig in gas pipeline

Quantization of magnetic flux leakage internal detection signals for composite defects of gas and oil pipelines

Shell's Auger Tension Leg Platform (TLP)in Garden Banks Block 426 has been installed in a record water depth of 2864 FSW(873 m). The two 12-inch oil and gas export pipelines from the TLP to shallow water platforms are also the deepest constructed to date in the Gulf of Mexico, requiring record breaking J-Lay construction technology. This paper describes design of the pipelines, including route selection, determination of the wall thickness, buckle arrestor and J-Lay collar design, and connection to the Auger TLP by means of first time use of a steel catenary riser. Construction topics discussed include a description of the deepwater J-lay system and a comparison of shallow water S-Lay and deepwater J-Lay. PIPELINESYSTEN DESCRIPTION The Auger pipelines were designed and constructed to transport oil and gas from Shell's Auger TLP located in the Deepwater Gulf of Mexico Garden Banks Area (GB426) to existing facilities in shallow water (Figure 1). The oil pipeline is a 12.75" (323.9 mm)outside diameter pipeline, 72 miles (116 km) in length, that runs from the TLP to one of Shell's existing platforms in the Eugene Island area (Block EI 331 'An) in a waterdepth of 250 ft (76 m). The gas pipeline is also 12.75" in diameter and runs from the TLP to Hess's existing platform in the Vermilion South Addition area (BlockVR397 'An) in a waterdepth of 397ft (121 m). The oil pipeline is designed for a 50 MBPD flow rate and the gas pipeline is designed to transport up to 150 14MSCoFfDnatural gas. Both pipelines are rated for ANSI 900service, or 2160psig (14.9 MPa)operating pressure. PIPELINE ROUTE SELECTION Several problems exist in routing deepwater pipelines in the Gulf of Mexico:large distance to existing shallow water pipeline infrastructure,generally very rough terrain in the deepwater region (beyond the 800 ft (244m)waterdepth contour),lack of reliable bottom contour and bottom feature data, andpresence of large areas classified by the Minerals Management Service as environmentally sensitive, which means that crossing of these areas by pipelines is prohibited. All these problems were present for the Auger TLP pipelines and route selection, including multiple surveys, required much more time and effort than at anytime in the past, Especially the oil pipeline routing faced the problem of having to circumvent environmentally sensitive areas and its final route is far from a straight line between the TLP and EI 331 "A" platform. Figure 1, which shows the routing of the deepwater portion of the pipelines, illustrates the impact of some of the problems caused by rough terrain. Because a portion of the pipeline (beyond the 1200- 1500foot waterdepth contour) could not be installed with conventional S-Lay, a choice had to be Dade:install a 20-mile-long section of each pipeline by first-time use of J-Lay along a smooth seabed, orlay as long as possible with S-Lay, and have only two 10-mile-longsections of J-Layed pipeline to install.

Since 2007, the pipeline industry has experienced a large increase in pipeline construction. Construction inspections performed by the Department of Transportation (DOT) Pipeline Hazardous Materials Safety Administration (PHMSA) have revealed numerous quality issues. These inspections, coupled with several pre-commissioning pressure test failures, first year in-service failures, and other material and construction problems, brought construction quality to the attention of the oil and gas pipeline industry. A proven method for improving quality in other industries is through the implementation of a quality management system (QMS). One widely accepted QMS used across industries is ISO 9001. Additionally, several QMS standards specific to the oil and gas industry have been developed. Due to the uniqueness of pipeline construction projects, PHMSA solicited proposals in 2013 for a research and development project titled, “Improving Quality Management Systems for Pipeline Construction Activities” which was awarded to and co-funded by DNV GL. This paper describes the QMS framework for pipeline construction activities and an accompanying guidance document developed by DNV GL. The framework and guidance document are intended to assist pipeline operating companies and contractors in the development and implementation of a company-specific QMS, with a goal of elevating the focus on quality to the level of safety. The framework adopts a risk-based, process approach, as defined in other QMS and management system documents, and follows the plan-do-act-check methodology. The QMS framework is designed to be scalable for a wide range of pipeline construction projects, including liquid and gas transmission pipelines and gas distribution lines. The framework includes the general management system components, as well as specific sections on implementation of a QMS for a pipeline construction project. The QMS framework and guidance document developed are intended to be used either as a stand-alone management system or as the quality component in a company’s corporate management system.

A comprehensive and objective risk evaluation model of oil and gas pipelines based on an improved analytic hierarchy process (AHP) and technique for order preference by similarity to an ideal solution (TOPSIS) is established to identify potential hazards in time. First, a barrier model and fault tree analysis are used to establish an index system for oil and gas pipeline risk evaluation on the basis of five important factors: corrosion, external interference, material/construction, natural disasters, and function and operation. Next, the index weight for oil and gas pipeline risk evaluation is computed by applying the improved AHP based on the five-scale method. Then, the TOPSIS of a multi-attribute decision-making theory is studied. The method for determining positive/negative ideal solutions and the normalized equation for benefit/cost indexes is improved to render TOPSIS applicable for the comprehensive risk evaluation of pipelines. The closeness coefficient of oil and gas pipelines is calculated by applying the improved TOPSIS. Finally, the weight and the closeness coefficient are combined to determine the risk level of pipelines. Empirical research using a long-distance pipeline as an example is conducted, and adjustment factors are used to verify the model. Results show that the risk evaluation model of oil and gas pipelines based on the improved AHP–TOPSIS is valuable and feasible. The model comprehensively considers the risk factors of oil and gas pipelines and provides comprehensive, rational, and scientific evaluation results. It represents a new decision-making method for systems engineering in pipeline enterprises and provides a comprehensive understanding of the safety status of oil and gas pipelines. The new system engineering decision-making method is important for preventing oil and gas pipeline accidents.

Generally, oil and gas pipeline is made of carbon steel, alloy steel and other metal materials. The biggest threat to the integrity of the oil and gas pipeline is the presence of corrosion. Corrosion will happened when the metal pipeline is affected by chemical or electrochemical attack, or microbial reaction with its environment. With the increasing of the service time, the corrosion of the oil and gas pipelines has become more and more serious. The wall thickness of the corroded pipeline will be lessened and that may lead the decrease of the strength of the pressurized pipeline. Thus, a leak may be happened at the corrosion area if the actual operation pressure of the pipeline is larger than the maximum safe pressure. So it is significant to study and assess the damage condition of the corroded oil and gas pipelines. Based on the theoretical foundations of fracture mechanics, the mathematical model for the failure pressure of corroded oil and gas pipelines was built in this paper firstly. And then, the corrosion damage level of the pipeline was divided into 3 grades according to the ability of the corroded pipeline. Furthermore, 20 corroded pipes were selected to study the damage assessment. The maximum safety operating pressure and damage level of each corroded pipe were carried out by applying the proposed mathematical model in the paper. As a result, the computational data were closed to the experimental data. The corrosion damage level and repair plan of the twenty pipes were discussed, and there were three pipes need to repair immediately. The results show that the proposed method can well assess the corrosion degree of the oil and gas pipelines with defects and can provide a scientific basis for the safe operation and emergency management of the oil and gas pipelines enterprise.

Corrosion potential is a fundamental electrochemical parameter critical to understanding the thermodynamic aspects of corrosion. Many corrosion theories are based on corrosion potentials. Corrosion potential is routinely and easily measured in the laboratory. In order to transfer this scientific knowledge from the laboratory to the field, it is necessary to determine the corrosion potential under operating field conditions. In this paper, the unique challenges measuring corrosion potentials in an industrial environment are described using measurements of the corrosion potentials of the internal surfaces of pipelines as examples.