From Installation to Operation: A Full-Scale Finite Element Modeling of Deep-Water Pipe-in-Pipe System

2009 ◽  
Author(s):  
Jason Sun ◽  
Paul Jukes
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
High Temperature ◽  
Deep Water ◽  
Compressive Load ◽  
Analysis Tool ◽  
Realistic Interaction ◽  
Global Buckling ◽  
Advanced Analysis ◽  
Lock In

Developments of deep water oil reservoirs are presently being considered in the Gulf of Mexico (GoM). Pipe-in-Pipe (PIP) systems are widely used and planned as the tie-back flowline for high pressure and high temperature production (HPHT) due to their exceptional thermal insulation capabilities. The installation of PIP flowline in deep water, disregarding the laying method, can present real challenges because of the PIP string weight. The effect of the lowering displacement as well as the lock-in compressive load acting on the inner pipe for the commonly used un-bonded PIP is also a major concern. Such effects will enhance the total flowline compression when the high temperature and high pressure are applied after start-up; they greatly increase the severity of the global buckling and result in local plastic collapse at a larger bending curvature section or strain localization area. An even greater concern is that industry fails to realize the seriousness of such failure potential, and the PIP is generally treated as a composite single pipe which does not evaluate the PIP load response correctly, especially the inner pipe lock-in compression omitted. It could result in an unsafe design for HPHT production. This paper endeavors to provide a trustworthy solution for the HPHT PIP systems from installation to operation by using the advanced analysis tool — “Simulator”, an ABAQUS based in-house Finite Element Analysis (FEA) engine. “Simulator” allows the PIP pipes being modeled individually with realistic interaction between the pipes. A systematic process was introduced by using a generic deep-water PIP flowline as a working example of J-Lay installation and HPHT production. The load and stress responses of the PIP at all installation stages were calculated with a high level of accuracy, they were then included in the global buckling analysis for the HPHT operation. The study demonstrated the effectiveness of Loadshare, an industry-leading solution; which reduces or eliminates the inner pipe lock-in compression and improves the PIP compressive load capacity for the high temperature operation.

Challenging Design Confronted in a Deepwater/HPHT PiP Tie-Back Flowline System

2013 ◽  
Author(s):  
Jason Sun ◽  
Sandra Jakl ◽  
Han Shi
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
High Energy ◽  
Lessons Learned ◽  
Design Stage ◽  
Length Variation ◽  
Analysis Tool ◽  
Load Effect ◽  
Strength Design ◽  
Advanced Analysis

A challenging problem that pipeline industry has to face in deepwater is the high energy reservoir with high pressure and high temperature. For piping, flowline, and riser, High Pressure (HP) leads to much thicker pipe wall that increases manufacturing and installation cost. High Temperature (HT) has even wider impact on design since the flowline system has to operate over a greater temperature range between non-producing situations such as installation and shut down, and the maximum production flow. Subsea tie-back to the existing floating production facility, generally named as Brown Field Development, has many engineering and financial advantages. It becomes more popular in the Gulf of Mexico (GoM), North Sea, and West African due to the economical benefits. This paper presents some of the design challenges of a deepwater subsea tie-back project, which is composed of an 8″ by 12″ pipe-in-pipe (PiP) flowline loop from three (3) subsea fields to a semi-submersible platform located in the GoM at a water depth of 2,000m (∼6,600ft). Some of key efforts are worth to mention: • Mitigation of thermal expansion and global buckling as facing very soft clay soil; • Transition tie-in of PiP to structure piping - a valiant strength design to meet the deepwater installation loading; • PiP inner pipe lock-in compressive load - effect of flowline (non-bonded) section length variation and locked-in stress; • Tight installation target box for the separately installed structure mudmat and upper module. This paper presents the solutions that Project team has generated to address these design/installation challenges. Lessons learned from the designs and installations are also presented. Advanced analysis tool — FEA are utilized through the entire design stage, from global 3-D flowline modeling to local component strength design.

Upheaval Buckling Analysis of Partially Buried Pipeline Subjected to High Pressure and High Temperature

2011 ◽  
Author(s):  
Jason Sun ◽  
Han Shi ◽  
Paul Jukes
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Soil Cover ◽  
Resistance Force ◽  
Soil Resistance ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Lateral Buckling ◽  
Upheaval Buckling ◽  
Global Buckling

Offshore industry is now pushing into the deepwater and starting to face the much higher energy reservoir with high pressure and high temperature. Besides the significant impacts on the material, strength, and reliability of the wellhead, tree, and manifold valve; high Pressure (HP) also leads to thicker pipe wall that increases manufacturing and installation cost. High Temperature (HT) can have much wider impact on operation since the whole subsea system has to be operated over a greater temperature range between the non-producing situations such as installation, and long term shut down, and the maximum production flow. It is more concerned for fact that thicker wall pipe results in much greater thermal load so to make the pipeline strength and tie-in designs more challenging. Burying sections of a HPHT pipeline can provide the advantages of thermal insulation by using the soil cover to retain the cool-down time. Burial can also help to achieve high confidence anchoring and additional resistance to the pipeline axial expansion and walking. Upheaval buckling is a major concern for the buried pipelines because it can generate a high level of strain when happens. Excessive yielding can cause the pipeline to fail prematurely. Partial burial can have less concern although it may complicate the pipeline global buckling behavior and impose challenges on the design and analysis. This paper presents the studies on the upheaval buckling of partially buried pipelines, typical example of an annulus flooded pipe-in-pipe (PIP) configuration. The full-scale FE models were created to simulate the pipeline thermal expansion / upheaval / lateral buckling responses. The pipe-soil interaction (PSI) elements were utilized to model the relationship between the soil resistance (force) and the pipe displacement for the buried sections. The effects of soil cover height, vertical prop size, and soil resistance on the upheaval and lateral buckling response of a partially buried pipeline were investigated. This paper presents the latest techniques, allows an understanding in the global buckling, upheaval or lateral, of partially buried pipeline under the HPHT, and assists the industry to pursue safer but cost effective design.

Life Prediction of the Tapered Pipe With High Temperature and High Pressure by Finite Element Methods

2007 ◽  
Author(s):  
Juntao Bao ◽  
Jianming Gong ◽  
Shantung Tu ◽  
Yuesheng Li ◽  
Yanfei Qiu
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
High Temperature ◽  
Internal Pressure ◽  
Creep Damage ◽  
Piping System ◽  
Bending Moments ◽  
Finite Element Program ◽  
Element Program ◽  
Main Steam

Tapered pipe used in the main steam pipelines, which operated at high temperature and high pressure, including concentric tapered pipe and eccentric tapered pipe, they are sources of weakness in the piping system serviced in the power stations and the chemical plants, and creep is the significant reason that caused their failure. Creep damage analyses are carried out for these two kinds of tapered pipes by introducing user subroutine based on the modified Karchanov-Rabotnov constitutive equations into finite element program ABAQUS, then the effects of bending moments and internal pressure to the serviced life of the components are investigated by comparing four group of calculated results under different loads, the results indicated that eccentric tapered pipe is more inclinable to broken than concentric tapered pipe under the same conditions, so it is not recommended to use the eccentric tapered pipe in the piping system. The bending moments will accelerate the components’ failure, so it is necessary to take some advantages to reduce the bending moments near the tapered pipe, on the other hand, the life of the tapered pipe will decrease quickly with the internal pressure increasing, so the control of the operated pressure is important to ensure the serviced life of the pipelines.

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