Pipeline Isolation Tool Testing & Analysis ProgramFALL 2018 PRCI PIPELINE TECHNICAL COMMITTEE MEETING (SAN DIEGO)PLUG-1-01 Piggable Plug Technology Project
Tuesday, October 23, 2018 | 1:30 to 2:00 PM
Presented by Chris Alexander
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Presentation Overview Program description Phases of work Technology companies and overview Finite element analysis Test sample configuration Schedule and billing Path forward
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Program DescriptionStress analysis / numerical modeling for pipe stresses induced by three isolation technologies, as well as validation by full-scale testing.
There is also a need to characterize the microscopic impact of the plug grips on inside surface of pipe’s having thin nominal wall thicknesses (compared to subsea pipelines).
The proposed program has been configured to evaluate competing technologies in an unbiased manner based on technical merits and observations.
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Phases of Work Phase 1: Industry Survey
Phase 2: Design review
Phase 3: Numerical modeling
Phase 4: Full-scale testing (current project stage)
Phase 5: FEA model calibration
Phase 6: Development of Parametric-based Tool
Phase 7: Post-testing inspection
Phase 8: Final reporting
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Technology Overview Proven high pressure isolation technology,
including 20+ years of success in the offshore pipeline market, but not optimized for onshore pipelines with applications that require: Low stress (thin walled pipeline)
Highly-piggable (1.5 D ~ 3D Bends)
Bi-directionally piggable
Cost competitive (versus Hot Tap, Plugging, or Line Purge)
Tetherless and remotely-operated
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The “Tools”PPIG
STATS
TDW
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Finite Element Modeling
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Report submitted to PRCI members in mid-JuneReport submitted to Tool Companies in mid-July
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General FEA Description Pipe size: 24-inch x 0.375-inch,
Grade X70
Plasticity of pipe material modeled using Ramberg Osgood approach
Only one plug module is modeled
1 x pipe outer diameter on each side of plug module
For the ovality cases, 1.5% ovality was assumed
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TDW Model (Exemplar)
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FEA ModelSlip Contact Surface
Packer Contact Surface
Space between Packer & Slips
High Pressure Side 1 x D
Low Pressure Side 1 x D
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FEA Model – Mesh• ABAQUS C3D8R “brick” element type.• 3 elements across wall thickness.• Transition from coarse to finer mesh
around the packer and slips.• Loading:
• Internal pressure (72% SMYS)• Packer pressure• Slips pressure• Slips axial load
DmaxDmin
Ovality Configuration
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Summary of ResultsCases
von Mises Stress (psi) [MPa]
Hoop Stress (psi) [MPa] Plastic Strain
PPIG 73,838 [502.2] 82,019 [565.5] 0.48%PPIG (Ovality) 73,172 [504.5] 83,455 [575.4] 0.54%
STATS 64,716 [446.5] 71,097 [490.2] 0.03%STATS (Ovality) 67,443 [465.0] 74,868 [516.2] 0.08%
TDW 70,140 [483.6] 77,494 [534.3] 0.21%TDW (Ovality) 71,185 [490.8] 80,148 [552.6] 0.29%
Cases Hoop Stress (psi) [MPa] Load Rating Factor
PPIG 82,019 [565.5] 1.17
STATS 71,097 [490.2] 1.01
TDW 77,494 [534.3] 1.11
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Results – Hoop Stress (OD)Units are in Pa(multiple by 0.000145 to get psi)
Tool Company: PPIG
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Results – Hoop Stress (ID)Tool Company: STATS
Units are in Pa(multiple by 0.000145 to get psi)
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Results - Deformation
Units are in meters (100X)
Tool Company: TDW
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Discussion The contact surface area between the grips
and the pipe inner wall play critical roles in the magnitude of stresses and how they are distributed.
The STATS isolation tool design incorporates two gaps on the grips’ surface, which creates a continuous surface in the axial direction.
The PPIG tool has the largest gap between each grip, the axial length of the grip is the largest.
Experimental validation of estimated stresses using strain gages is critically important.
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Path Forward Activities
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Test Sample Configuration(3 “replaceable” assemblies required)
900# Class “slip-on” 24-inch flanges with blinds (2 req’d per assembly);
include bolting and gaskets1-inch NPT HP couplings(4 req’d per assembly, final location TBD)
X XFabricate a basic support structure to hold the pipe, water, and tool (assume 10,000-lbs)
This 20-ft insert piece will be removed after each test and replaced by welding as shown
24-inch x 0.375-inch, Grade X70 pipe material(20-ft replacement piece)
24-inch x 0.375-inch, Grade X70 pipe material(30-ft total length per assembly)
24-inch x 0.375-inch, Grade X70 pipe material(30-ft total length per assembly)
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Project Status Phase 1: Industry Survey
Phase 2: Design review
Phase 3: Numerical modeling
Phase 4: Full-scale testing (current project stage)
Phase 5: FEA model calibration
Phase 6: Development of Parametric-based Tool
Phase 7: Post-testing inspection
Phase 8: Final reporting
Completed workOngoing work
Future (2019) work
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Path Forward Test assembly fabrication underway (testing to
be conducted early next year in 2019)
Prepare for modeling validation efforts using full-scale testing
Develop framework for analytical tool
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Dr. Chris Alexander, [email protected] | (281) 450-6642 (cell)