A New Approach to Pipeline Leak Detection Using Electromagnetic Sensing

Many different approaches have been adopted for identifying leaks in pipelines. Leak detection systems, however, generally suffer from a number of difficulties and limitations. For existing and new pipelines, these inevitably force significant trade-offs to be made between detection accuracy, operational range, responsiveness, deployment cost, system reliability, and overall effectiveness. Existing leak detection systems frequently rely on the measurement of secondary effects such as temperature changes, acoustic signatures or flow differences to infer the existence of a leak. This paper presents an alternative approach to leak detection employing electromagnetic measurements of the material in the vicinity of the pipeline that can potentially overcome some of the difficulties encountered with existing approaches. This sensing technique makes direct measurements of the material near the pipeline resulting in reliable detection and minimal risk of false alarms. The technology has been used successfully in other industries to make critical measurements of materials under challenging circumstances. A number of prototype sensors were constructed using this technology and they were tested by an independent research laboratory. The test results show that sensors based on this technique exhibit a strong capability to detect oil, and to distinguish oil from water (a key challenge with in-situ sensors).

Pipeline Diagnostics With Ultrasonic Meters

Canada and the United States have vast energy resources, supported by thousands of kilometers (miles) of pipeline infrastructure built and maintained each year. Whether the pipeline runs through remote territory or passing through local city centers, keeping commodities flowing safely is a critical part of day-to-day operation for any pipeline. Real-time leak detection systems have become a critical system that companies require in order to provide safe operations, protection of the environment and compliance with regulations. The function of a leak detection system is the ability to identify and confirm a leak event in a timely and precise manner. Flow measurement devices are a critical input into many leak detection systems and in order to ensure flow measurement accuracy, custody transfer grade liquid ultrasonic meters (as defined in API MPMS chapter 5.8) can be utilized to provide superior accuracy, performance and diagnostics. This paper presents a sample of real-time data collected from a field install base of over 245 custody transfer grade liquid ultrasonic meters currently being utilized in pipeline leak detection applications. The data helps to identify upstream instrumentation anomalies and illustrate the abilities of the utilization of diagnostics within the liquid ultrasonic meters to further improve current leak detection real time transient models (RTTM) and pipeline operational procedures. The paper discusses considerations addressed while evaluating data and understanding the importance of accuracy within the metering equipment utilized. It also elaborates on significant benefits associated with the utilization of the ultrasonic meter’s capabilities and the importance of diagnosing other pipeline issues and uncertainties outside of measurement errors.

Implementation of CSA Z662-15 Annex K Option 2 on a 610mm Liquid Pipeline

For more than two decades, CSA Z662 Annex K has provided a method for developing alternative acceptance criteria for weld flaws in mechanized welded pipelines. Increasingly, over the years, fracture mechanics practitioners have found the method overly conservative and restrictive with respect to brittle fracture criteria when compared to other accepted fracture mechanics-based engineering critical assessment ECA codes and methods. These limitations rendered the CSA Annex K method difficult to implement on pipelines constructed with materials not possessing optimal toughness and in cases requiring consideration of fracture toughness at temperatures lower than the typical minimum design metal temperature (MDMT) of −5°C. This paper presents experiences implementing CSA Z662-15 Annex K Option 2 methodology on a 610 mm diameter liquids pipeline and compares and contrasts the utility and benefits of the code revision. This pipeline required consideration for installation during winter months, necessitating installation temperatures as low as −30°C. In addition to evaluation of actual ECA results, analytical evaluations of the Option 2 methodology were also conducted considering parameters outside those used on the project. The new Annex K Option 2 method was found to be of considerable benefit in preparation of a practical ECA. Since fracture toughness testing was conducted at the anticipated lowest installation temperature, the flaw criteria were, as expected, principally controlled by elastic/plastic crack growth consideration. The failure assessment diagram implemented into the CSA Z662-15 Annex K Option 2 provided tolerance for both longer and deeper flaws than that afforded by Option 1 (which resorts to the former 2011 Annex K method). Furthermore, the reduced restriction to the surface interaction ligament (p distance) offers additional advantages including increased flexibility in weld profile design and weld pass sequencing. Fracture toughness (CTOD) testing of TMP pipeline steels used in the project at −30°C often produced transitional fracture toughness results. It was found that the particular project materials were quite sensitive to the level of test specimen pre-compression (an acceptable plastic straining method to reduce residual stress gradients) applied to the CTOD specimens to enhance fatigue crack-front straightness. It was found that optimizing the level of pre-compression (to achieve acceptable pre-crack straightness while minimizing plastic pre-strain) achieved a balance between fully satisfying testing requirements, providing a conservative assessment of CTOD, and facilitating a functional Annex K ECA.

Oil Pipeline Standoff Leak Detection: A Novel Approach for Airborne Remote Detection of Small Leaks

While natural gas pipelines already benefit from airborne, remote detection of leaks [1, 2], oil pipeline leak detection has been for a long time reliant on SCADA systems limited in their capability to detect very small leaks, and/or visual inspection of the right of way (line flyers, pipeline employees or members of the public). This paper presents a novel and complementary way of detecting small leaks (i.e. sensitivity of 0.1 L/minute, 1 barrel/day) of oil (crude or refined products) using an optical detection system mounted on an airborne platform (UAV, plane or helicopter). The scope of this paper is based on the requirements provided by TransCanada, namely sensitivity (herein referred as LOD — Limit of Detection) and accuracy (herein referred as spatial resolution) as similar to their description in API 1130, while the topic of reliability is addressed in our noted concerns on the false alarms that may be generated in Infrared-DiAL based systems due to soil reflectivity. Robustness, as described in API 1130, was out of scope. Keeping in mind the requirement of airborne operation, three different approaches for the detection of leaks along long pipeline ROWs were studied. Infrared Differential Absorption lidar (IR-DiAL), UltraViolet Raman lidar (UV-Raman lidar) and UltraViolet Laser-Induced Fluorescence lidar (UV-LIF lidar) have been tested in realistic conditions. In the first round of tests, laboratory spectral measurements of vapors in a closed cell were performed. In the second round of tests, the breadboards were placed in a mobile laboratory and the light beams aimed at a large open at 40 to 50 meters and reflected off a sand target. Finally, the mobile laboratory with the breadboards was installed at ∼40 meters from a leak simulator. The leak simulator was made by using a large sand container in which petroleum products were leaked. Intermediate scale leak simulator tests showed that it is clearly a challenge to correlate a measured concentration to an actual leak size. Tests have also shown that there is a strong concentration gradient in the air above a leak. This indicates that a better overall detection performance should be obtained with a measurement using the air next to the ground, and that it is feasible to detect a leak of less than 1 barrel/day. UV-Raman tests performed in the outdoors suggested a Limit Of Detection (LOD) of the system below 1 500 ppm-m when detecting all hydrocarbons. Because of the hardware that would be needed to lower this detection limit, results suggest abandoning the Raman technique for remote leak detection from an airborne platform. IR-DiAL showed the best sensitivity for the detection of hydrocarbons (< 1 ppm-m of LOD). However the effective LOD will be reduced because of the soil spectral reflectance variations that may lead to a high false alarm rate for concentrations of hydrocarbons lower than 235 ppm-m. The UV-absorption approach was also briefly tested, suggesting a LOD for benzene of between 1.5 and 2.5 ppm-m. The UV absorption of benzene is not affected by ground spectral reflectance variations. This is an approach that will be investigated further.

Fracture Behavior in West Jefferson Test Under Low-Temperature Condition for X65 Steel Pipe With High Charpy Energy: Current Activities in HLP Committee, Japan, Report 1

This paper describes the results of pressure vessel fracture test which called West Jefferson and/or partial gas burst testing using Grade API X65 linepipe steel with high Charpy energy that exhibits inverse facture in the Drop Weight Tear Test (DWTT). A series of pressure vessel fracture tests which is as part of an ongoing effort by the High-strength Line Pipe committee (HLP) of the Iron and Steel Institute of Japan (ISIJ) was carried out at low temperature in order to investigate brittle-to-ductile transition behavior and to compare to DWTT fracture behavior. Two different materials on Fracture Appearance Transition Temperature (FATT) property were used in these tests. One is −60 degree C and the other is −25 to −30 degree C which is defined as 85 % shear area fraction (SA) in the standard pressed notch DWTT (PN-DWTT). The dimensions of the test pipes were 24inches (609.6 mm) in outside diameter (OD), 19.1 mm in wall thickness (WT). In each test, the test pipe is cooled by using liquid nitrogen in the cooling baths. Two cooling baths are set up separately on the two sides of the test vessel, making it possible to obtain fracture behaviors under two different test temperatures in one burst test. The test vessel was also instrumented with pressure transducers, thermocouples and timing wires to obtain the pressure at the fracture onset, temperature and crack propagation velocity, respectively. Some informative observations to discuss appropriate evaluation method for material resistance to brittle facture propagation for high toughness linepipe materials are obtained in the test. When the pipe burst test temperatures are higher than the PN-DWTT transition temperature, ductile cracks were initiated from the initial notch and propagated with short distance in ductile manner. When the pipe burst test temperatures were lower than the PN-DWTT transition temperature, brittle cracks were initiated from the initial notch and propagated through cooling bath. However, the initiated ductile crack at lower than the transition temperature was not changed to brittle manner. This means inverse facture occurred in the PN-DWTT is a particular problem caused by the API DWTT testing method. Furthermore, results for the pipes tested indicated that inverse facture occurred in PN-DWTT at the temperature above the 85 % FATT may not affect the arrestability against the brittle fracture propagation and it is closely related with the location of brittle fracture initiation origin in the fracture appearance of PN-DWTT.

Development of an Effective ASME IX Welding Procedure Qualification Program for Pipeline Facility and Fabrication Welding

For cross country pipeline welding in Canada, welding procedures shall be qualified in accordance with the requirements of CSA Z662 Oil and Gas Pipeline Systems. For pipeline facility and fabrication welding on systems designed in accordance with CSA Z662 or ASME B31.4, welding procedures qualified in accordance with the requirements of ASME Boiler & Pressure Vessel Code Section IX are permitted and generally preferred. Welding procedures qualified in accordance with ASME IX provide advantages for pipeline facility and fabrication applications as a result of the flexibility achieved through the larger essential variable ranges. The resulting welding procedures have broader coverage on material thickness, diameter, joint configuration and welding positions. Similarly, ASME IX is more flexible on welder performance qualification requirements and accordingly a welder will have wider range of performance qualifications. When applied correctly, the use of ASME IX welding procedures often means significantly fewer welding procedures and welder performance qualifications are required for a given scope of work. Even though ASME IX qualified welding procedures have been widely used in pipeline facility and fabrication welding, it is not well understood on how to qualify the welding procedures in accordance with ASME IX and meet the additional requirements of the governing code or standard such as CSA Z662 in Canada. One significant consideration is that ASME IX refers to the construction code for the applicability of notch toughness requirements for welding procedure qualification, yet CSA Z662 and ASME B31.4 are both silent on notch toughness requirements for welding procedure qualification. This paper explains one preferred method to establish and develop an effective ASME IX welding procedure qualification program for pipeline facility and fabrication welding while ensuring suitability for use and appropriate notch toughness requirements. The paper discusses topics such as base material selection, welding process, welding consumable consideration and weld test acceptance criteria.

Cybersecurity From Field to Host

Remote communications to field devices for data monitoring and controls has greatly reduced operating costs, reduced downtime, and helped to optimize our industry. With the ever growing threat of cyber-attacks, the need for securing that data is becoming a more common topic of discussion. Whether collecting SCADA or Measurement data from the field, doing remote configuration, or even sitting dormant, it is important to keep the line of communication to your devices secure. This presentation will discuss potential threats and examples of cyber-attacks. It will cover industry standards, types of cyber security, and the importance and best practices for securing data for Measurement and/or SCADA and control systems.

Overpressure Protections in Liquid Pipeline Hydraulic Design

Continuous economic development demands safe and efficient means of transporting large quantities of crude oil and other hydrocarbon products over vast extensions of land. Such transportation provides critical links between organizations and companies, permitting goods to flow between their facilities. Operation safety is paramount in transporting petroleum products in the pipeline industry. Safety can affect the performance and economics of pipeline system. Pipeline design codes also evolve as new technologies become available and management principles and practices improve. While effective operation safety requires well-trained operators, adequate operational procedures and compliance with regulatory requirements, the best way to ensure process safety is to implement safety systems during the design stage of pipeline system. Pressure controls and overpressure protection measures are important components of a modern pipeline system. This system is intended to provide reliable control and prevent catastrophic failure of the transport system due to overpressure conditions that can occur under abnormal operating conditions. This paper discusses common pressure surge events, options of overpressure protection strategies in pipeline design and ideas on transient hydraulic analyses for pipeline systems. Different overpressure protection techniques considered herein are based on pressure relief, pressure control systems, equipment operation characteristics, and integrated system wide approach outlining complete pressure control and overpressure protection architecture for pipeline systems. Although the analyses presented in this paper are applicable across a broad range of operating conditions and different pipeline system designs, it is not possible to cover all situations and different pipeline systems have their own unique solutions. As such, sound engineering judgment and engineering principles should always be applied in any engineering design.

Development of Grade X80 High Charpy Energy Linepipe by MA Formation Control

Higher grade linepipes such as grade X80 have been developed and applied to long distance pipelines in order to reduce the cost of pipeline construction by using thinner pipes than is possible with conventional grades. Service pressures have also been increased in recent years for efficient gas transportation. In addition to the requirement of higher strength, running ductile fracture should be prevented in long distance and high pressure pipelines. Resistance to ductile fracture, as evaluated by Charpy energy, is an important material property for higher grade linepipes. It has been reported that bainite single-phase steel tends to show higher Charpy energy than ferrite-bainite or bainite-MA (martensite-austenite constituent) dual-phase steels, since void nucleation is suppressed in single-phase steels compared with dual-phase steels. However, in higher grade steels with a bainite single phase, a small amount of MA grains generally remains due to the chemical stability of MA. Therefore, further reduction of MA is key to improving Charpy energy for higher grade linepipe steels. In order to achieve high Charpy energy by MA formation control, the optimum conditions of the plate manufacturing process were investigated. As a result, a high Charpy energy was achieved by the combination of controlled rolling and precise control of the accelerated cooling conditions, by which the MA phase was minimized. Based on the above investigation, grade X80 high Charpy energy linepipes were trial-produced by applying JFE Steel’s optimized accelerated cooling (ACC) system with a high cooling rate and homogeneous temperature profile. Stable higher Charpy energy was achieved by minimizing MA formation and achieving a homogeneous microstructure by advanced cooling control.

Optimization of Planning and Scheduling of Refinery Product Based on Downstream Requirements

The disconnect between the optimization systems of upstream production and downstream demand poses a legitimate problem for China’s refined oil industry in terms of overproduction waste. Established methods only partially model the refinery system and are unable to integrate detailed production plans or meet market demands. Therefore, the research on production scheduling optimization combined with the demand of downstream pipeline network has very real applications that not only reduce the consumption of human/material resources, but also increase economic efficiency. This paper aims to optimize the production scheduling of refined oil transportation based on the demand of downstream product pipelines by analyzing the relationships between crude oil supply, refinery facility capacities and refinery tanks storage. The new model will minimize the refined production surplus therefore minimizing refinery costs and wastage. This is done by implementing models custom designed to optimize the three subsystems of the overall process: oil product blending scheduling optimization, producing and processing equipment scheduling optimization, and mixed crude oil scheduling optimization. We first analyzed the relationship between all the production units from the crude oil to the distributional destinations of oil products. A mathematical model of the refinery production scheduling was then built with minimum total surplus inventory as the objective function. We assumed a known downstream demand and used a step by step model to optimize oil stocks. The oil blending plan, production scheduling, amount of crude oil, and refined oil mixing ratios were all derived from the model using three methods: a nonlinear method called Particle Swarm Optimization (PSO), the simplex method and the enumeration method. The evidence laid out in this paper verifies our models functionality and suggests that systems can be significantly optimized by using these methods which can provide solutions for industries with similar challenges. Optimization of the refinery’s overall production process is achieved by implementing models for each of the three distinguished subsystems: oil blending model, plant scheduling model, and the mixed crude oil refining model. The demand dictates the final production quantities. From those figures we are able to place constraining limits on the input crude oil. The refined oil production scheme is continuously enhanced by determining the amount of constituent feed on the production equipment according to the results of previous production cycle. After optimization, the minimum surplus inventory of the five oil components approach their lower limits that were calculated using our models. We compare the literature on scheduling optimization challenges both in China and abroad while providing a detailed discussion of the present situation of Chinese refineries. The interrelationships of production processes on each other are revealed by analyzing the system and breaking it down to three fundamental parts. Basing the final production predictions on the downstream demand, we are able to achieve a minimum refinery surplus inventory by utilizing a comprehensive refinery scheduling model composed of three sub-models.