Sandwich Pipe for Long Distance Pipelines: Flow Assurance and Costs

2016 ◽  
Author(s):  
Segen F. Estefen ◽  
Marcelo Igor Lourenço ◽  
Junkai Feng ◽  
Claudio Moura Paz ◽  
Dirney Bessa de Lima
Keyword(s):  
Thermal Insulation ◽  
Cost Evaluation ◽  
Thick Wall ◽  
Flow Assurance ◽  
Long Distance ◽  
Steel Pipes ◽  
Slowing Down ◽  
Innovative Solutions ◽  
Structural Configurations ◽  
Offshore Industry

The low oil prices have produced severe impact on the offshore industry slowing down new projects. The projects to become economically feasible shall incorporate innovative solutions for subsea equipment. In this context, the use of sandwich pipes for deepwater scenarios can be a useful alternative to conventional long distance pipelines. Sandwich pipe is a new concept composed of two concentric steel pipes separated by and bonded to a cement annulus that provides a combination of high structural strength with thermal insulation. For ultra deepwater scenarios, related to water depths beyond 1,500 m, the single wall steel pipe requires very thick wall and high insulation capacity. In this work, structural configurations for single wall pipe (SW), pipe-in-pipe (PIP) and sandwich pipe (SP) are designed for several deepwater scenarios. Collapse and buckling propagation are considered to overcome the high pressure environment while flow assurance is considered to overcome the low temperature. Simulations on flow assurance and cost evaluation will provide the basis for the comparative studies and recommendation about the appropriate scenarios for sandwich pipe applications. Flow assurance was simulated with OLGA software for the considered scenarios to avoid solid deposition. The costs related to each pipeline technology are finally compared for the established scenarios, and the sandwich pipe was considered to be a promising technology when high collapse strength and good thermal insulation are required.

Flow Assurance in Deep-Water Gas Pipelines: Locating Hydrate Plugging Position in a Fast Way

2021 ◽  
Author(s):  
Jing Yu ◽  
Cheng Hui ◽  
Chao Wen Sun ◽  
Zhan Ling Zou ◽  
Bin Lu Zhuo ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Deep Water ◽  
Pipe Wall ◽  
Gas Pipeline ◽  
Flow Assurance ◽  
Gas Pipelines ◽  
Long Distance ◽  
Hydrate Layer ◽  
Hydrate Deposition ◽  
Water Gas

Abstract Hydrate-associated issues are of great significance to the oil and gas sector when advancing the development of offshore reservoir. Gas hydrate is easy to form under the condition featuring depressed temperature and elevated pressure within deep-water gas pipeline. Once hydrate deposition is formed within the pipelines, the energy transmission efficiency will be greatly reduced. An accurate prediction of hydrate-obstruction-development behavior will assist flow-assurance engineers to cultivate resource-conserving and environment-friendly strategies for managing hydrate. Based on the long-distance transportation characteristics of deep-water gas pipeline, a quantitative prediction method is expected to explain the hydrate-obstruction-formation behavior in deep-water gas pipeline throughout the production of deep-water gas well. Through a deep analysis of the features of hydrate shaping and precipitation at various locations inside the system, the advised method can quantitatively foresee the dangerous position and intensity of hydrate obstruction. The time from the start of production to the dramatic change of pressure drop brought about by the deposition of hydrate attached to the pipe wall is defined as the Hydrate Plugging Alarm Window (HPAW), which provides guidance for the subsequent hydrate treatment. Case study of deep-water gas pipeline constructed in the South China Sea is performed with the advised method. The simulation outcomes show that hydrates shape and deposit along pipe wall, constructing an endlessly and inconsistently developing hydrate layer, which restricts the pipe, raises the pressure drop, and ultimately leads to obstruction. At the area of 700m-3200m away from the pipeline inlet, the hydrate layer develops all the more swiftly, which points to the region of high risk of obstruction. As the gas-flow rate increases, the period needed for the system to shape hydrate obstruction becomes less. The narrower the internal diameter of the pipeline is, the more severe risk of hydrate obstruction will occur. The HPAW is 100 days under the case conditions. As the concentration of hydrate inhibitor rises, the region inside the system that tallies with the hydrate phase equilibrium conditions progressively reduces and the hydrate deposition rate slows down. The advised method will support operators to define the location of hydrate inhibitor injection within a shorter period in comparison to the conventional method. This work will deliver key instructions for locating the hydrate plugging position in a fast way in addition to solving the problem of hydrate flow assurance in deep-water gas pipelines at a reduced cost.

Spun Steel Pipes for the Offshore Industry

1983 ◽  
Vol 105 (1) ◽  
pp. 97-102 ◽  
Author(s):  
A. Royer ◽  
B. Dumas ◽  
M. Gantois
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Centrifugal Casting ◽  
High Strength ◽  
Controlled Rolling ◽  
Climatic Conditions ◽  
Casting Technique ◽  
Steel Pipes ◽  
Potential Applications ◽  
Offshore Industry

Many parts either for sea-line pipes as “buckle” or “crack arrestor,” or for structures may require the use of wall tubular products with high mechanical properties. Such heavy-wall pipes may be produced by centrifugal casting. Two Mn-Mo steels have been developed for medium-wall pipes (e≤35 mm) to be used under very severe climatic conditions: an acicular ferritic steel, a pearlite reduced steel produced by controlled rolling techniques [1, 2, 3]. More alloyed chemical composition and heat-treatments are needed to produce heavy-wall pipes. Then, production of such pipes is more difficult and sometimes impossible. Observations made on controlled-rolled Mn-Mo steel led to a better understanding of the influence of metallurgical structures and chemical composition on steel characteristics. Similar metallurgical structures can only be reached via other routes, for example centrifugal-casting of steel associated with heat-treatment, lead to the production of heavy-wall pipes with high strength and suitable transition temperature. After a brief description of the centrifugal casting technique, we introduce the grades developed for heavy-wall pipes with yield strength up to 100,000 psi. The mechanical properties, Battelle, fatigue, static bending, C.O.D., weldability, etc., of Centrishore II are given and compared to other materials. Possible offshore applications and other potential applications of parts produced by centrifugal casting are described.

Assessing the risk of hydrate plug formation: a new probability and management tool

2015 ◽  
Vol 55 (2) ◽  
pp. 477
Author(s):  
Zachary Aman ◽  
Bruce Norris ◽  
Michael Johns ◽  
Eric F. May
Keyword(s):  
New Technologies ◽  
Water Concentration ◽  
Operating Conditions ◽  
Management Tool ◽  
Flow Assurance ◽  
Long Distance ◽  
The Past ◽  
Hydrate Plug ◽  
Plug Formation ◽  
Low Dosage

As production moves towards harsher operating conditions, the conventional strategy of complete hydrate avoidance may not be economically viable. In the past two decades, the development of new technologies, such as low-dosage hydrate inhibitors and active pipeline heating, have enabled new management strategies where limited quantities of hydrate may be allowed to form without endangering the flowline. While this strategy may result in cost savings for long-distance tiebacks, its success hinges on accurate predictive capabilities for hydrate formation and transportability. In this extended abstract, the authors present a new freeware Hydrate Flow Assurance Simulation Tool (HyFAST), where the risk of hydrate plug formation can be directly predicted in subsea flowlines for use in flow assurance concept selection and process engineering. This tool is based on deterministic hydrate plug formation stages—including phase dispersion, hydrate growth rate and particle agglomeration—developed in the international engineering community in the past 20 years. HyFAST expands this conventional paradigm by introducing a new probabilistic engine to account for dynamic hydrate nucleation. This expanded capability enables flow-assurance engineers to directly quantify the risk of plug formation as a function of: flowline length; insulation thickness; produced water concentration; the amount of thermodynamic inhibitor injected; and, the amount of low-dosage hydrate inhibitor injected. An open discussion of all models and assumptions underlying the tool is presented, and the use of this tool to quantify hydrate plug formation risk is demonstrated.

Thermal Insulation With Latent Energy Storage for Flow Assurance in Subsea Pipelines

2015 ◽  
Author(s):  
Mohammad Parsazadeh ◽  
Xili Duan
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Thermal Insulation ◽  
Phase Change Materials ◽  
Heat Transfer Analysis ◽  
Flow Assurance ◽  
Pipeline System ◽  
Fluid Temperature ◽  
Latent Energy ◽  
Subsea Pipelines

Flow assurance is critical in offshore oil and gas production. Thermal insulation is an effective way to reduce heat loss from subsea pipelines and avoid the formation of hydrates or wax deposits that could block the flowlines. This paper presents heat transfer analysis from a subsea flowline with different insulation materials, particularly with nano-enhanced phase change materials (NPCMs) that allow thermal energy storage in the pipeline system. The phase change materials (PCMs) can effectively regulate fluid temperature during production fluctuations or increase the cool-down time during production shutdown. This paper considers a pipe in pipe configuration with different insulation methods; the cool-down times are calculated and compared. The results show that thermal insulation can greatly delay the fluid cool-down process. A significant improvement of cool-down time can be achieved with PCM energy storage under a good conventional insulation layer. Moreover, with nanoparticles in a PCM, the latent energy storage is enhanced thus it takes even longer time for the internal fluid to reach its hydrate formation temperature.

The Next Generation Fast Marine Access Solution

2021 ◽  
Author(s):  
Albert A.K. Rijkens ◽  
Gerard J. Poen ◽  
Remco D. Schipperen
Keyword(s):  
Integrated Design ◽  
Design Approach ◽  
Operational Cost ◽  
Next Generation ◽  
Long Distance ◽  
Long Distance Transport ◽  
Comfort Levels ◽  
Integrated Design Approach ◽  
Offshore Industry ◽  
Distance Transport

The long distance transport of offshore personnel has traditionally been undertaken by air. However, the desire for increased safety and efficiency in combination with the drive to lower operational cost in the offshore industry opens up new possibilities for fast marine access solutions. This article presents the development of the next generation Fast Crew Supplier that combines high transit speeds at high comfort levels with a reliable, safe and comfortable method of personnel exchange to the platform using a Walk-to-Work solution. The results of an integrated design approach are presented which are used to optimize the main transfer systems and their controls. It is shown that optimization of these systems allows a high workability for a Walk-to-Work solution on a fast and relatively lightweight ship in challenging wave conditions.

The Welding Deformations of Stainless Steel Pipes With Thick Wall by Narrow Gap Gas Tungsten Arc Welding

2010 ◽  
Author(s):  
Jainxun Zhang ◽  
Chuan Liu ◽  
Jing Niu
Keyword(s):  
Stainless Steel ◽  
Arc Welding ◽  
Welding Process ◽  
Gas Tungsten Arc Welding ◽  
Thick Wall ◽  
Fe Model ◽  
Narrow Gap ◽  
Steel Pipes ◽  
Gas Tungsten Arc ◽  
Gas Tungsten

The austenitic stainless steel pipes with thick wall are widely used in the nuclear power station and are welded by narrow gap gas tungsten arc welding process. The welding deformations of multi-pass butt-welded pipes with 65 and 70mm thickness are investigated experimentally and numerically in the paper. The transient axial deformation and axis shift deformation are measured during welding. An axisymmetric FE model and a thermal mechanical calculating procedure are presented to simulate the welding axial deformations. An effective calculating method by only considering the contraction of each welding pass in the model is proposed. The experimental results show that the axis shift deformation is very small and demonstrates an elastic movement during welding; the axial shrinkage of welded pipes is the mainly deformation, which is very significant during the first several weld pass, and decreases sharply after the weld groove has been filled at the height of 30% wall thickness that makes the stiffness of pipes large enough to resist the welding shrinkage.

Insulation Performance of Sandwich Pipe

2018 ◽  
Author(s):  
Jiankun Yang ◽  
Segen F. Estefen ◽  
Marcelo Igor Lourenço Souza ◽  
Yuxi Wang ◽  
Cheng Hong
Keyword(s):  
Steady State ◽  
Comprehensive Evaluation ◽  
Flow Assurance ◽  
Insulation Material ◽  
Flexible Pipe ◽  
Long Distance ◽  
Severe Condition ◽  
Promising Alternative ◽  
Offshore Oil Industry ◽  
Insulation Performance

As the tendency of the offshore oil industry is going deeper and further, the subsea pipeline is exposed under tougher condition combining lower temperature with higher hydrostatic pressure. The severe condition creates a challenge towards flow assurance, which often results in a high cost solution. Reducing the cost while providing a qualified insulation performance is of great significance to deepwater development. For ultra-deepwater beyond 1500m, single-wall pipe usually fails to meet the flow assurance requirements or requires a huge amount of insulation material. Pipe-in-pipe configuration can provide a good insulation performance but comes with a high cost associated. Sandwich pipe is a new concept composed of two concentric steel pipes separated by a cementitious composite annulus that provides a combination of high structural strength with thermal insulation. It is reported to be a promising alternative for both flexible and rigid conventional pipes in applications for long distance pipelines. In order to further investigate its feasibility in deep waters, a subsea production system with depth at 2200m was used as a case study for a comprehensive evaluation of insulation performance of the sandwich pipe, including both steady-state and shut-in working conditions. For a comparative study, scenarios using single-wall pipe (SW), pipe-in-pipe (PIP) and flexible pipe (FP) were also considered separately. The results showed that (i) sandwich-pipe performs better in steady-state but worse in between shut-in and the restart period (ii) sandwich-pipe with larger diameter performs better than it with smaller diameter. The reasons for the sandwich pipe behavior were discussed and suggestions to improve the performance are presented.

Technology Focus: Subsea Systems (August 2021)

2021 ◽  
Vol 73 (08) ◽  
pp. 48-48
Author(s):  
Birger Velle Hanssen
Keyword(s):  
Oil And Gas ◽  
New Technologies ◽  
Hydrate Formation ◽  
Gas Production ◽  
Sensor Technology ◽  
Flow Assurance ◽  
Detailed Knowledge ◽  
Oil Viscosity ◽  
Long Distance ◽  
Produce Water

Flow assurance in subsea oil and gas fields often presents significant challenges. Every field has its own combination of difficulties, and no universal process or system can be used to mitigate these. Detailed knowledge across a broad range of competencies, therefore, is required to find solutions that can minimize the risk of not getting the hydrocarbons safely to the process facilities. Many subsea fields that are being developed today are long tiebacks, taking advantage of existing offshore infrastructure or producing directly to shore. These developments must deal with the long-distance transport of hydrocarbons in deep cold water, commonly increasing the risk of hydrate formation and wax deposition, for example. In addition, large elevation changes from deep water to surface and topographical challenges along the pipeline can create flow-regime effects that can hinder production. The loss of temperature in a long subsea pipeline also creates challenges for fields that produce heavy oil because the oil viscosity in some cases increases dramatically at low temperatures, in addition to effective viscosities increasing because of oil and water emulsions. Other phenomena such as scale deposition, foaming, sand production, erosion, and corrosion must be considered and dealt with as well. Various smart-technology innovations for subsea oil and gas production contribute to reducing the risk of these flow-assurance issues. Some of them are described in this month’s selected SPE papers. A good example is as follows: When wells start to produce water, the operator needs to understand where the water is coming from and quantify volumes in order to start a mitigation program to avoid hydrate formation. This is one of the reasons why subsea multiphase flowmeters have become an essential feature in all new subsea fields. The most common remedy for flow-assurance problems is probably the use of chemical additives. A sensor technology that can directly determine the ratio between produced water and chemicals such as monoethylene glycol has been recently introduced in subsea production systems. This measurement enables the optimization of chemical-injection rates, thereby contributing to significant savings in capital expenditure (reduced design margins) and operational expenditure (reduced overdosage margins). Another effective way to prevent hydrates and wax is to keep the process temperature above critical limits by applying active flowline heating. New technologies for highly reliable and efficient subsea electrically heat-traced flowlines have recently been qualified, industrialized, and installed. Technologies as described here can play an important role in future subsea field developments. The recommended readings for this feature date back further back in time than usual, but are relevant to the theme of this year’s main selections. Recommended additional reading at OnePetro: www.onepetro.org. OTC 29232 Real-Time Subsea Hydrate Management in the World’s Longest Subsea Tieback by Christophe Vielliard, OneSubsea, a Schlumberger Company, et al. OTC 31078 Electrically Heated Trace Flowline on the Ærfugl Project—A Journey From Product Qualification to Offshore Campaign by Guy Mencarelli, Subsea 7, et al. SPE 195784 A New Flow-Assurance Strategy for the Vega Asset: Managing Hydrate and Integrity Risks on a Long Multiphase Flowline of a Norwegian Subsea Asset by Stephan Hatscher, Wintershall Norge, et al.

Failure Prediction for Pressurized Thick Wall Circumferentially Welded CrMoV Steel Pipes under High Temperature

2013 ◽  
Vol 631-632 ◽  
pp. 951-956
Author(s):  
Kun Rong Jia
Keyword(s):  
Power Plants ◽  
Weld Zone ◽  
Failure Prediction ◽  
Parent Material ◽  
Thick Wall ◽  
Heat Affect Zone ◽  
Steel Pipes ◽  
Weld Material ◽  
Failure Life ◽  
Hoop Stresses

The failure Prediction for thick wall CrMoV steel pipes circumferentially welded was studied using the Finite Element Method (FEM) under close-ended, open-ended and axial compression conditions, respectively. The life span of failure, redistribution of stress on the welds and damage variations were obtained using damage modeling. Since there is a distinct mismatch of mechanical properties in parent material, weld material and heat affect zone, variations of damage with time, stress redistribution and failure life in each zone are different. The FEM results show that the weakness of the welds is the heat-affected zone (HAZ) where the hoop stresses increase sharply in the tertiary stage of creep. The maximum of damage of the welds lies on the inner surface of in the weld zone when failure occurs. The information is useful for assessing the performance of practical service welds in power plants pipe work.

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