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There are few deepwater-pipeline operators with expertise in pipeline repairs. This paper describes a strategy developed and implemented on deepwater-pipeline intervention, based on a deepwater operational experience built over a decade. A methodology is proposed for design of subsea flowlines and risers coupled with a subsea high-integrity pressure protection system (HIPPS) for fields with high shut-in tubing pressure (SITP). Systematic experimental and modeling approaches to designing a safe operating strategy for a 5-km deepwater-subsea-flowline case study are presented to address unplanned shutdown and restart events for waxy-crude production.
There are few deepwater-pipeline operators with expertise in pipeline repairs. This paper describes a strategy developed and implemented on deepwater-pipeline intervention, based on a deepwater operational experience built over a decade. The market for subsea vessel operations in field development; inspection, repair, and maintenance (IRM); and subsea well intervention is expected to grow 63% during 2012 to 2016.
The natural gas pipeline is co-financed by the EU, with work beginning immediately. The hunt for global alternatives to store crude oil includes offshore, global strategic reserves, pipelines, rail cars, and trucks. Westcoast Energy revised its inspection practices following the 2018 incident. Shell has begun to examine the innovative technologies that could shift the inspection paradigm. Delfin Midstream announced advancements in partnership with Samsung Heavy Industries and Black & Veatch.
The two companies worked together in 2019 to improve execution techniques where Petrofac digitalized maintenance and inspection activity. Low prices will constrain maintenance and modifications in the coming year. However, maintenance can only be delayed so long, leading to a long-term outlook of growth in the market for maintenance, modifications, and operations. There are few deepwater-pipeline operators with expertise in pipeline repairs. This paper describes a strategy developed and implemented on deepwater-pipeline intervention, based on a deepwater operational experience built over a decade.
The amount of oil and gas resources approved for development last year surpassed 20 billion BOE, the highest level seen since 2011. Telltale signs have emerged that we are entering a new offshore investment cycle. The project aims to contribute an estimated ultimate recovery of more than 175 MMboe from one of the company’s signature deepwater projects in the US Gulf of Mexico. Following a 42-day journey from Singapore, the Liza Destiny has arrived at the Stabroek Block offshore Guyana, where it is expected to produce up to 120,000 gross boe/D from the ExxonMobil-operated deepwater project upon startup. Phase 1 production from the deepwater US Gulf of Mexico field is expected to reach 30,000 BOPD.
Fugro and SEA-KIT’s partnership will develop unmanned vessels, while HII and Kongsberg will market naval and maritime products. Sensors, robots, and artificial intelligence have made their way into a number of areas within the industry, including pipeline inspections. Shell has begun to examine the innovative technologies that could shift the inspection paradigm. The subsea operations company said its most recent campaign is the first fully unmanned offshore pipeline inspection completed “over the horizon,” surveying up to 100 km from the shore. Saipem is taking the lead in advancing the capabilities of FlatFish, an autonomous underwater vehicle being developed by Shell for commercial application by 2020.
Nair, Aravind (DNV GL) | Jaiswal, Vivek (DNV GL) | Fyrileiv, Olav (DNV GL) | Vedeld, Knut (DNV GL) | Zheng, Haining (ExxonMobil) | Huang, Jerry (ExxonMobil) | Tognarelli, Michael (BP) | Goes, Rafael (Petrobras) | Bruschi, Roberto (Saipem) | Bartolini, Lorenzo (Saipem) | Vitali, Luigio (Saipem)
To date, there are no publicly available, validated tools or industry accepted guidelines for the assessment of Vortex-Induced Vibration (VIV) fatigue of rigid Jumper (spool) systems. The existing state of practice has been to treat rigid jumper systems as free spanning pipelines and apply the associated design principles in DNV GL recommended practice DNV-RP-F105/DNVGL-RP-F105 (Free Spanning Pipelines). However, widely used rigid jumper systems such as the M-shape jumper systems are subjected to complex flow fields around their legs and bends and fall outside of the test data used to generate the free-span response model in DNV GL Recommended Practice (RP). A Joint Industry Project (JIP) ‘Jumper VIV JIP’ that included BP, ExxonMobil, Petrobras, Saipem and DNV GL was conducted between Dec. of 2014-2016 to collectively tackle the technical issues related to the VIV design of rigid jumper systems.
Through the JIP study, measured responses from ExxonMobil's jumper tow test data were used to develop new response curves for jumper systems in pure-current condition. Curves for in-line and cross-flow responses were initially developed by classifying the measured responses into in-line or cross-flow directions and compared against the existing DNVGL-RP-F105 response curves. Due to potential ambiguity in classification and application to Jumper Design, a more general curve that does not rely on directional classification has also been generated. Due to the differences in behavior of rigid jumper systems to that of free spanning pipelines, a new VIV guidance report was developed as part of the JIP deliverable. Principles and philosophies in the DNV-RP-F105 were followed in the development, but with the intent of identifying unique behavior of jumper systems for a subsequent update of the RP.
This paper presents the Guidance notes from the JIP and forms the first release of Jumper VIV fatigue assessment approach to the Industry. ExxonMobil's model test data, the only known test data available in the industry, was used in the development of unique response model and the new design guidance. The paper includes the new response model along with VIV screening, safety factors and unique considerations required for fatigue assessment of jumper systems.
Deep water pipelines operating under high pressures and temperatures are susceptible to gradual global axial movements over a number of heating and cooling cycles – A phenomenon known as axial walking. These cyclic axial movements that occur in high pressure-high temperature(HPHT) offshore pipelines are usually induced by four mechanisms: Seabed slopes along the pipeline route Riser base tension induced by a steel catenary riser at the end of a pipeline Thermal transients during startup/shutdown cycles Multiphase flow behaviour like slug-induced flows, start up, shut down and ramp up operations
Seabed slopes along the pipeline route
Riser base tension induced by a steel catenary riser at the end of a pipeline
Thermal transients during startup/shutdown cycles
Multiphase flow behaviour like slug-induced flows, start up, shut down and ramp up operations
Several mitigation measures for pipeline walking as a results of these mechanisms have been developed and studied over the years with the most common being the use of hold-back anchors installed either at the middle or the end of a pipeline, the latter being the preferred method. Historically, estimation of the required anchor force to restrict pipeline axial movement has been premised on the amount of soil frictional resistance required to equal the driving force due to temperature and pressure. This methodology can lead to erroneously high estimates of the required anchor force for walking mitigation, leading to large-sized pipeline anchors with an attendant increase in capital expenditure associated with pipeline projects. This paper estimates, with a higher degree of accuracy, the required anchor force to mitigate axial walking due to seabed slope or steel catenary riser(SCR) tension.
The methodology described in this work involves the use of a mathematical proof to show that the magnitude of the walking mitigation force for a pipeline susceptible to walking is directly proportional to the pipeline submerged weight. The solution was also validated by a finite element analysis(FEA). The finite element analysis was carried out using the multipurpose industry FEA tool, Abaqus with the pipeline modelled using beam elements and the soil modelled using three dimensional analytically rigid elements. The coulomb friction model was used with frictional forces defined in the axial direction only.
Several cases were analysed in Abaqus using several pipeline sizes and soil friction coefficients in order to validate the analytical results. The analytical and FEA results agree quite well and show that the restraining force required to mitigate pipeline walking due to global seabed slope and SCR tension is solely dependent on the pipeline submerged weight and SCR tension respectively.
This paper proffers a cost-effective mitigation to seabed slope and SCR induced walking by showing that pipeline walking mitigation is not dependent on the magnitude of the axial friction resistance which usually requires large mitigation forces to counter the large frictional forces that may result particularly when we have a fairly long pipeline.
Nilsen-Nygaard, Viktor (Equinor ASA) | Hanssen, Ståle (Equinor ASA) | Groenewegen, Matthijs (Allseas Engineering B.V.) | Vlaanderen, Stef (Allseas Engineering B.V.) | Apeland, Kjell Edvard (Equinor ASA) | Berge, Jan Olav (Equinor ASA) | Instanes, Frode (Equinor ASA) | Armstrong, Michael A. P. (Isotek Oil&Gas Ltd)
In order to deliver on the ambitious schedule for the Johan Sverdrup development, the operator and the Johan Sverdrup-partners also needed to make some innovative bets on new technology. This paper explores two areas - innovations in installation and pipeline technology - that played a key role in the development of the mega-project. In particular the decision to qualify and become the world s first user of the single-lift installation technology developed for the vessel Pioneering Spirit ended up changing the very concept for construction, installation and completion of three of the four topsides that make up the Johan Sverdrup field center in the first phase of the development. The technology - developed by the installation contractor and qualified for first use worldwide by the operator - saved an estimated 2.5 million offshore manhours from the offshore completion phase, which significantly reduced safety risks and helped shave months off the development schedule. The first-ever use of the technology to install topsides took place in June 2018 with the singlelift installation of the drilling platform topsides on the Johan Sverdrup field. And in March 2019, the two remaining topsides weighing a total of 44,000 tonnes were lifted in place in the span of only 3 days, including the heaviest offshore lift ever executed with the installation of the 26,500 tonnes processing platform. The paper also intends to explore how the same innovative mindset and focus also played a role in introducing new pipeline technology - in particular, the world s first use of remote-controlled and diverless hyperbaric welding of the ''36 oil export pipeline to the Johan Sverdrup riser platform. The paper also discusses how the project benefited from further industrialization of the hot-tapping technology used for the first time by the operator in 2012 on the Åsgard subsea project, when connecting the Johan Sverdrup gas export pipeline to the'live' Statpipe gas pipeline.
The main objective of this paper is to demonstrate a cost-effective, user-friendly and highly reliable subsea pipeline and subsea structure design automation method developed on a cloud-based digital field twin platform. The FEED and detail design phase of the subsea pipeline and subsea structures are normally quite long and need to run several analyses sequentially to achieve the desired results. In this cloud-based design automation method, a significant number of calculation hours are saved due to systematic and sequential approach with minimum remediation work by reducing human error.
In this proposed design automation framework, all the standard pipeline and subsea structure design calculations including code checks based on design standards are performed through a web-based graphical user interface (GUI) designed in cloud-based digital field twin. In the design phase of the subsea pipeline, some more advanced level pipeline finite element analyses are performed for buckling and walking assessment. The design phase of the subsea pipeline consists of different analytical as well as finite element (FE) calculations which are performed systematically and sequentially in cloud-based digital field twin. Various pipeline engineering calculations are performed sequentially and systematically in the cloud using the metadata information available from the digital field data. Some of the standard engineering calculations implemented in the digital field twin are wall thickness calculation (based on design standards), on-bottom stability analysis, span analysis, pipe end expansion analysis, pipeline global buckling analysis etc. All the standard pipeline and subsea structure design calculations are developed in python, which is connected to the cloud-based digital twin through API. For advanced FE analyses for lateral buckling and pipeline walking, the preliminary susceptibilities are assessed through analytical calculations developed through python-based API. For the pipeline FE analysis for lateral buckling and walking assessment, pre-processor and post-processor are developed in python based on various metadata (pipe data, soil, environment) information available in the subsea digital field.
The pipeline design calculation outputs are stored in a standardised report format in the cloud platform. The proposed GUI developed for the pipeline and structural design automation is user friendly and the whole process is automated through the python API. This design automation approach significantly reduces the total project cost. Digital Field Twin integrate all the subsea pipeline and structural design calculations and automate the report generation. The proposed digital field twin is very much beneficial for the early stages in the projects where some changes are expected.
This subsea pipeline and structural design automation system built on the cloud-based digital field twin through API so that it works as an integrated system giving 3D digital field diagram to perform all the design calculations in one digital platform.