Developments in 3 Layer PE Coating for Pipeline Protection

Three Layer Polyethylene (3LPE) coating for onshore pipelines have been used in India since the early 1980’s and have reached a level of maturity. The combination of Gas barrier by FBE layer and moisture barrier with mechanical and UV protection by black PE layer makes it better than either standalone FBE or 2LPE coatings. Further developments in PE materials makes 3LPE coating suitable for a design temperature range of −50°C to +90°C which practically covers all the onshore Oil pipelines in all geographies with excellent outdoor weathering resistance. It has also been possible to provide end-to-end protection with new PO Melt film technology that can give “factory applied” quality girth weld coating on site with complete fusion of girth weld coating with the parent coating, making it a hermetically sealed pipeline. This paper also discusses couple of the failure and success stories of 3LPE coating and their analysis.

Offshore Oil and Gas Pipeline: Flow Assurance and Corrosion Modelling for Inspection Prioritization

Flow modelling and corrosion risk assessment are used to study a challenging multiphase pipeline, where the main focus is the identification and prioritization of critical locations for direct inspection (DA). Through the internal corrosion direct assessment (ICDA), flow modelling sensitivity studies is carried out to identify critical locations with risks of high shear stresses and water holdup. Through corrosion risk assessment (CRA), the critical locations were narrowed down to four primary locations, which through direct inspection could provide the information necessary to estimate the overall pipeline condition. It is highlighted that without the In-line inspection (ILI) data, selection of inspection locations becomes problematic. However, carrying out a CRA in combination with dynamic flow modelling can build a more representative analysis and assist with effective engineering decision making. One of the available industry standard tools that can assist with demonstration of pipelines’ integrity requirement is an approach that integrates flow assurance with corrosion modelling known as Internal Corrosion Direct Assessment (ICDA). More specifically, an industry standard multiphase dynamic flow model (OLGA) with well-established corrosion models, CRA and engineering judgement have been employed to identify and prioritize inspection locations. A benefit of this work is the validation of predictions by both OLGA and the corrosion engineer in close adoption to the procedures of the NACE ICDA standard practice. Considerations from corrosion engineering aspect on modelling requirements and corrosion diagnosis will be presented, where the primary focus is on identification of hot spots and consequent inspection requirements in order to limit excavation activities and provide cost-effective solutions to the client.

Risk Based Inspection (RBI) Implementation in Cross Country Petroleum Pipelines

Risk Based Inspection (RBI) is a risk assessment and management process that is focused on loss of containment of pressurized equipment in processing / transportation facilities, due to material deterioration / degradation. These risks are managed primarily through threat identification, inspection, monitoring and mitigation measures. Risk Based Inspection (RBI) process is focused on maintaining the mechanical integrity of high pressure pipelines and minimizing the risk of loss of containment due to deterioration. Frequency of inspection & monitoring activities are fixed in cost effective way which based on the risk ranking. This paper discusses the development, implementation and maintaining a risk-based inspection (RBI) program for high pressure long petroleum pipelines. It provides guidance to operators of pressure-containing pipelines for developing and implementing an inspection program. This technical paper includes means for assessing an inspection program and its plan. The approach emphasizes safe and reliable operation through risk-prioritized inspection and monitoring program. This also includes practical implementation case study of Wolrd’s longest heated crude oil pipeline operated and maintained by M/s Cairn India Limited.

Free Span Rectifications in Submarine Pipeline Projects: A Case Study

Seabed features along a subsea pipeline route are highly stochastic. Free spans may be created in the pipelines due to seabed irregularities, subsequent scouring, and horizontal movements of pipeline during operation. It is quite common to encounter free spanning sections along the pipeline route from the very start till the end. Spanning of subsea pipelines is a primary area of concern not only in the detailed design and installation stage but also during the operation stage. For ensuring the pipeline safety during operation, underwater surveys must be conducted at suitable intervals. The frequency of such pipeline free spanning surveys depends on the operators’ interest and the statutory requirements. The static and dynamic characteristic of the pipeline spans should be investigated to ensure that the pipeline can be operated within acceptable safety levels. The unsupported spans that incur static as well as dynamic loads on the pipeline, may lead to vortex-induced vibrations and ultimately fatigue, and thus affecting the pipeline serviceability and design life. Vortex induced vibrations are not allowed to occur in the operation life as far as the conventional design is considered but DNV - RP - F105 allows the onset of vortex induced vibrations provided that the fatigue damage due to vortex induced vibrations doesn’t exceed the allowable values. Pipe soil interaction has a huge impact on the pipeline design as well as the pipeline service life. Analysis of the existing conditions and stress levels based on the site-specific surveys and environmental data needs to be carefully carried out for determining the acceptability of spans and the effective intervention works if required. Hydrological studies and numerical modeling may also need to be carried out for sediment transportation analysis and for proper assessment & quantification of sea bed erosion, trenching and backfilling requirements. In the present work, the acceptable criteria in terms of static and dynamic stresses and fatigue damage limits due to vortex induced vibrations as per DNV - RP - F105 have been discussed. Further comprehensive analysis philosophy and the criticalities in the design analysis for free spanning of subsea pipeline are presented. A case study based on an offshore project in western India has been presented involving the major project issues. The main areas of concerns & challenges faced are examined in detail. Further study has been conducted for the other available strategic solutions in the VIV mitigation and rectification of free spanning sections.

Pressurfect™ CNG-Advanced Material Grade for High Pressure CNG Fuel Line Applications

In line with the government of India’s philosophy of going green to reduce emission levels in cities there is a thrust to increase the gas distribution network. With an increase in CNG vehicles, comes the safety of the people and we need to ensure that Safety is not comprised at any level. To follow the Safety aspect, CNG is an excellent alternate fuel which can be used to minimize risks and increase life of the vehicles. Since this gas is used at very high pressures (in the range of 230–250 bar) and under severe conditions, special tubing must be used for the transportation to gas stations and in the vehicles. Therefore, the tubing should be able to not only withstand high pressure of the gas within but also the corrosion issues arising due to the extreme conditions the tubes within. Sandvik did an extensive study of the conditions and came up with a material which is specifically developed for this high pressure application. The high pressure line is of Stainless Steel 316L but this material comes with certain modifications for this particular requirement. In this tubing the C content is lowered to 0.025% for better corrosion resistance, Ni is min 13% along with Mo min 2.5% this makes sure that the material not only has sufficient passivation properties but the strength also to withstand that kind of a pressure. Alongside a special production route also has been developed for the manufacturing of these tubing. This ensures Safety for the people throughout the life of the vehicle.

HSE and City Gas Distribution

City Gas Distribution is one of the most assured businesses in current times as Natural Gas being a clean fuel becomes the first choice of consumers. Though CGD Network has enormous potential and has evident advantages however, it brings alongwith it’s own challenges but the biggest challenge is the vicinity of CGD Network with common public. A major factor for success of CGD Network depends on the discipline and involvement of common public in keeping CGD Network safe and effective. This paper intends to discuss on HSE issues with focus on like Single Call system for India, Indian regulations Vs other countries and Quality Assurance. Single Call system for India is the most important issue of CGD Network that really needs to be deliberated. In India, more than 20 clearances need to be obtained from various statutory and civil authorities before execution of any CGD Network project which really affects the project cost, time, consumer benefits, emergency response and third party damages. Now let’s consider few international regulations like National Energy Board in Canada which is the nodal agency to ensure CGD pipelines are safe for public and environment. NEB regulations harmonize with provinces to ensure that any third party excavation work within pipeline corridor is carried out only after due communication to the pipeline company. The 49 US Code 60114 - One Call notification system also mandates that any third party before carrying out any excavation needs to establish if there are underground facilities present in the area of the intended activity and contact appropriate system. Indian regulations like T4S and ERDMP for CGD Network are indeed bringing all CGD companies at par in terms of design, safety, O&M and Integrity Management System. However, they need to sincerely look into Single Call System alongwith specific issues like interdistances, space constraints in big cities, compressor installation at height. Quality Assurance involves periodic inspection and maintenance of CGD asset through a systematic plan including identification of critical equipments, Preventive Maintenance Schedules, carrying out maintenance as per the PM, maintaining a database of observations and defects. A key component is the generation of baseline data for implementing and monitoring Integrity Management System for CGD Network. Hence, as CGD Network is a complex and dynamic distribution system involving public, private industries/commercials, civil authorities and wide geography, it is imperative to have a multi-pronged approach involving strict regulation enforcement, well informed public and latest technologies to ensure safe and efficient CGD Networks.

The Automated System for Line Pipe’s Dimensions Measurement

With the advent of automated measurement of physical dimensional parameters of steel line-pipes, the industry seems to have scaled newer heights, which were previously never even imagined. The dimensional accuracy of each pipe is very critical in the overall success of a line pipe project. The quality of girth welding of pipes during laying, depends upon the close dimensional tolerances of the pipe ends. Even a slight variation in out-of-roundness or end-chamfered profile could lead to drastic irregularities in the pipe-to-pipe joining process. And the manual measuring of the pipe parameters poses a serious question with regards to their accuracy and reliability, due to the effects of man, measurement method and instruments used. There is also a huge limitation of the sampled area measured not exactly resembling the whole pipe, due to the constraints of time and the manual process involved. This paper describes the rise of Automated Pipe Dimension Measurement System (APDMS), which measures a total of 19 dimensional parameters after real-time geometrical & trigonometrical calculations, using parametric data from 72 measurement laser scanners & sensors. The pipe coordinates are measured by laser triangulation technique principally, at each degree circumferentially and 10 mm apart lengthwise. A pipe that needs at least 45 minutes to measure all dimensional parameters manually, by 2 men and almost 25 instruments & accessories, is measured in 2.5 minutes by APDMS with mind-boggling resolution and accuracy. All this is done with a simple push of a button after one-time entering of pipe size. The fully automated system then does its job efficiently to move the pipe accordingly and scan it. The back-end software calculates the required parameters from the measured raw coordinates, evaluates them against set criteria, viz. upper and lower limits, and generates a plot that shows the variation of a parameter along the length or circumference. A calibration system in incorporated to keep the system compliant with accuracy against calibrated and certified standard samples. Initially, we took more than 2000 trials on the whole range of pipe sizes we manufacture, after the installation of system on shop-floor. After trials and establishment, we have so far measured more than 3000 regular production pipes through this system with remarkable results. Analysis has been carried out continuously to ensure the repeatability and reproducibility of the system is as per industry standards. This new, contactless method aims to minimize dimensional variances for fluent and effortless installation of pipes at application site, by ensuring that the dimensions are well within the defined criteria, at each and every point on the pipe during its manufacturing.

Internal Corrosion Predicted and Found in Refined Piggable Product Pipeline Through ICDA

Contaminants such as CO2, H2S and O2 in liquid and gas pipelines in the presence of water create an aggressive environment conducive to internal corrosion. During pipeline operations, solids deposition, water accumulation, bacterial activities and improper chemical inhibition aggravate the internal corrosion attack. For assessing the threat of internal corrosion the industry has only three integrity validation tools at its disposal. These are Pressure Testing, In Line Inspection (ILI) and Internal Corrosion Direct Assessment (ICDA). To enhance pipeline integrity for piggable and non-piggable pipelines, NACE International published a variety of Standard Practices for the ICDA protocols for predicting time-dependent internal corrosion threats for various products in both offshore and onshore in sweet or sour service. All ICDA protocols are a structured, iterative integrity assessment process, consisting of the following four steps: Pre-assessment, Indirect Inspection, Detailed Examination and Post-assessment. Most importantly, unlike ILI and pressure testing, all ICDA standards require a mandatory root cause analysis and a go forward mitigation plan to arrest the corrosion processes being encountered. This paper reviews one case study; LP-ICDA for three (3) “piggable” refined product pipelines from the Jetty to the onshore marketing terminal. This paper will be useful for the pipeline operators to provide guidance on not only identifying the locations at which internal corrosion activity has occurred but also look into how the operators used the ICDA program to better manage their asset.

Pipeline Repairs: The History of the Technology and the Efforts to Codify and Document Standards

This paper will review the history of pipeline repairs. Prevailing codes, standards , design guidance’s and regulation typically permit several types of repairs: namely: replace pipe as a cylinder, repair by grinding or buffing out a defect, weld overlays techniques, utilizing a steel reinforcement sleeve or utilizing a composite reinforcement sleeve or composite wrap. This paper will review the history of the technology and the efforts to document and codify consensus standards such as ASME PCC 2 Article 4.1, ASME B31.8s, ASME B31.4 and ISO 24817. Contemporaneous issues related to the subject will be addressed as well of the durability of the aforementioned repair methods. Globally pipeline operators are required to operate their pipelines in a safe and reliable manner, preventing any unplanned loss of containment, and ensuring the asset continues to run reliably delivering a profit for the pipeline owner/operator. Most pipeline operators are required to maintain their pipelines to an approved code either by National Regulators and/or insurers with the aim of improving safety of the pipeline and unplanned losses of containment. Most National Regulators guidance for the repair of pipelines refers to either ASME B31.4 for liquid pipelines and B31.8(S) for gas pipelines, while for process piping most operators complete repairs following the ASME PCC2 Article 4 guidelines. These guidelines are credible and are globally accepted as being an effective method to operate and maintain pipelines. This paper with reference to the three ASME guidelines highlighting the acceptable repair methods and also looks at the requirements of ISO TS 24817 and highlights how this does and does not fit into the maintenance of high pressure pipelines.

The Impact of Crossing Design, Geotechnical Data, Drilling and Survey Techniques on the Economics Execution and of Extreme Length HDD Crossings

Over the years the drilled river crossing industry has matured through important developments and advancements, extending the probability of achieving significantly longer crossings. Stronger rigs, higher quality drill pipe and smart intersect survey techniques are a few of the areas showing improvement. Executing a long length crossing involves a high competency level from personnel, high quality reliable equipment and general construction resources over a longer period of time as compared to a more standard HDD crossing. Consequently a relatively large financial investment is necessary and significant cash flow capabilities. This requires drilling companies to step up job preparation, planning and overall organisation and to follow a detailed scenario with each step of the operation assessed and engineered, tools and support equipment selected and arranged and checked with all work methods written down in detail. Providing an elaborate plan and organisation to guarantee maintenance and repair of all sorts of equipment on site with systems in place to stock, trace and deliver wear & tear parts at short notice. Preventing the operation coming to a standstill caused by technical problems.