Minimum Wall Thickness Requirements for Ultra Deep-Water Pipelines

Torselletti, Enrico; Vitali, Luigino; Bruschi, Roberto; Collberg, Leif

doi:10.1115/omae2003-37219

Cited by 4 publications

(2 citation statements)

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“…An increase of wall thickness and sometimes yield strength is the obvious approach to improve the collapse capacity. Torselletti et al 4 state that collapse becomes the most critical design aspect in ultra-deep waters as there are limitations on how thick line pipes can be manufactured by the mills. Depending on the pipe diameters, there are also limitations on the tension capacity associated with different installation vessels in order to hold the weight of the submerged pipe string in the catenary.…”

Section: Challengesmentioning

confidence: 99%

Deepwater pipelines – status, challenges and future trends

Fyrileiv

Aamlid

Venas

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part M:

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The demand for energy is steadily increasing and, at least for the coming decades, the world has to rely on oil and gas to address this need. Most of the easiest accessible offshore petroleum reservoirs have been discovered and a great part developed over the last six decades. Thus, development of new oil and gas fields faces a lot of challenges as most of them are in remote areas, in deep waters and/or in areas with extreme environments like the Arctic region. One of the major trends in the offshore petroleum industry points towards deeper waters (e.g. outside West Africa, the Brazilian Pre-Salt developments and in the Gulf of Mexico). This trend also includes increased use of subsea installations instead of platforms, more subsea processing and increased use of pipelines to transport the hydrocarbons to shore or into a pipeline grid. This paper addresses some of the challenges pipeline design, installation and operation may face in deep and ultra-deep waters. The main design challenge is related to the high external pressure that may cause collapse of the pipeline. This potential failure mode is normally dealt with by increasing the pipe wall thickness, but at ultra-deep water depths this may require a very thick walled pipe that becomes very costly, difficult to manufacture and hard to install due to its weight. One approach to overcome this is to improve some of the parameters that determine the collapse resistance by an improved manufacturing process. Other approaches are to ensure a minimum internal pressure is maintained in the pipeline during all phases, or to install a buoyant pipeline that is anchored at a moderate water depth rather that laying on the sea bed.

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Section: Challengesmentioning

confidence: 99%

Deepwater pipelines – status, challenges and future trends

Fyrileiv

Aamlid

Venas

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part M:

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“…The propagation buckling pressure was determined in the context of the tests performed on one pipe in each of the "as-received" and thermally treated states. The following equation can be found in DNV Offshore Standard OS-F101 [5], taking no account of additional safety margins: The fabrication factor α fab allows for the reduction in compressive yield strength frequently observed in the past in circumferential direction of pipes produced using UOE process [6], [7], [8]. Figure 14 shows a comparative assessment of calculated propagation buckling pressures and data obtained experimentally.…”

Section: Propagation Bucklingmentioning

confidence: 99%

Collapse Testing of Thermally Treated Line Pipe for Ultra-Deepwater Applications

DeGeer¹,

Marewski

Hillenbrand³

et al. 2004

23rd International Conference on Offshore Mechanics and Arctic Engineering, Volume 3

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The Mardi Gras Transportation System is an ultra deepwater pipeline system that will support a number of prospects in the Gulf of Mexico, including the Holstein, Mad Dog, Atlantis and Thunder Horse field developments. To support the design of the deepest portions of the Mardi Gras Transportation System, a full-scale collapse test program was performed, and was aimed at measuring, quantifying and documenting the increase in pipe strength and collapse resistance as a result of the thermal induction heat treatment effect (thermal aging) from the pipe coating process. This paper presents a summary of the test program and the results of all testing performed on Europipe pipe samples. Two collapse tests and five pressure + bend tests were performed on as-received and thermally treated pipe specimens. These specimens were API Grade X65 line pipe, with an outer diameter of 28 inches (711 mm) and a wall thickness of 1.5 inches (38 mm). Geometric measurements, material coupon tests, and ring expansion tests were also performed. The coupon tests also included specimens taken from the original plate samples from which the full-scale pipes were manufactured, providing data on the effect of the UOE process on circumferential compressive strength. For the thermally treated pipe specimens, thermal treatment was performed by running the specimens through a pipe coating mill, simulating a fusion bond epoxy coating operation. This process involved preheating specimens to 240°C using induction heating. Subsequent material and full-scale tests on these specimens resulted in an increase of cross-sectional residual stresses by almost threefold, an increase of the circumferential compressive yield strength of the pipe by approximately 23% and an increase of pipe collapse strength by approximately 28%. The results of these tests are also compared to the collapse and collapse + bending equations found in the DNV (DNV OSF101) and API (API RP 1111) offshore pipeline codes, as well as the collapse equations found in API Bul 5C3 for downhole casing applications. In particular, it has been shown that the thermal treatment of the UOE pipe specimens can increase the DNV fabrication factor from 0.85 to 1.0.

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Collapse Limit of Thermally Treated Line Pipe Under Combined External Pressure and Bending Deformation

Sakimoto¹,

Tajika²,

Handa³

et al. 2022

Journal of Offshore Mechanics and Arctic Engineering

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This study discusses the collapse criteria for thermally-treated line pipe and their bending interaction against collapse based on a full-scale test under external pressure with and without bending loading. The critical collapse strain in the pressure bending test was much higher than that estimated by the DNV-ST-F101 standard because it was calculated based on estimating collapse pressures without bending interaction based on SMYS of design pipe in the standard. However, the collapse pressures without bending interaction in fullscale test was significantly higher than that of the estimation according to DNV-ST-F101 standard. The effect of the thermal heat cycle simulated anti-corrosion coating heating on line pipe collapse criteria is also discussed based on the change of yield stress of pre-strained and thermally-treated material. As the maximum heat cycle temperature increases, the reduction of the compressive yield stress along circumferential direction by the Baushinger effect due to UOE process becomes small. It is thought that a DNV equation for estimating the critical bending strain to collapse will provide a more accurate estimation of the critical collapse pressure and strain for thermally-treated line pipe when the collapse pressure is calculated considering the change of strength parameters due to the tensile pre-strain level and heat cycle temperature.

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Minimum Wall Thickness Requirements for Ultra Deep-Water Pipelines

Cited by 4 publications

References 0 publications

Deepwater pipelines – status, challenges and future trends

Deepwater pipelines – status, challenges and future trends

Collapse Testing of Thermally Treated Line Pipe for Ultra-Deepwater Applications

Collapse Limit of Thermally Treated Line Pipe Under Combined External Pressure and Bending Deformation

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