APTECH's Pipeline Experience
The projects that are summarized here will provide an introduction to our experience:
Liquids Line - Third Party Damage
APTECH analyzed a liquids line failure that resulted in significant river water pollution. We performed the failure analysis and confirmed that a prior mechanical damage incident was the root cause of the failure. We performed finite element analyses to define the local stresses at a dented location in the pipe and, using a probabilistic fracture mechanics based fatigue analysis, we were able to define the most likely time that the damage occurred.
The projects that are summarized here will provide an introduction to our experience:
- Incident Investigations
- Liquids Line - Third Party Damage
- Natural Gas Line Collapse
- Offshore Pipeline Fracture Mechanics Analysis
- Design Support - Offshore Pipeline Risk
Analysis
- Design Support - Alaskan Natural Gas
Transmission System (ANGTS)
- Onshore Pipeline Risk Analyses
Liquids Line - Third Party Damage
APTECH analyzed a liquids line failure that resulted in significant river water pollution. We performed the failure analysis and confirmed that a prior mechanical damage incident was the root cause of the failure. We performed finite element analyses to define the local stresses at a dented location in the pipe and, using a probabilistic fracture mechanics based fatigue analysis, we were able to define the most likely time that the damage occurred.
Offshore Pipeline Fracture Mechanics
Analysis
In this project, APTECH analyzed the significance of pre-existing weld imperfections in an offshore line that was laid in the South China Sea. On subsequent review of the circumferential weld radiographs by the owner, it was concluded that linear indications were present in the welds. Using fracture mechanics procedures based on API 1104, we were able to conclude that the imperfections did not constitute a fracture risk. We also concluded that fatigue was not a life limiting condition.
Design Support - Offshore Pipeline Risk Analysis
APTECH was part of the Technology Development team for the proposed Oman-to-India natural gas pipeline. We were responsible for hazard scenario identification for all phases of the project (design, installation, and operation) and developed probabilistic risk assessments for the major hazard scenarios. The analyses resulted in a risk ranking of the key hazards based on realistic cost assessments of the consequences and evidence-based predictions of the likelihood. APTECH also contributed to issues related to fracture control, weld quality, pipeline collapse, and overall quality assurance programs.
Design Support - Alaskan Natural Gas Transmission System
In this project, APTECH provided design support for materials selection for the line pipe and compressor stations for the proposed transport of chilled natural gas. We developed the fracture control plan for the line pipe and welds and also used the result to tailor the inspection program and quality assurance plan. The reports on APTECH’s work were part of the submittal to a Federal Energy Regulatory Commission (FERC) for the project.
In this project, APTECH analyzed the significance of pre-existing weld imperfections in an offshore line that was laid in the South China Sea. On subsequent review of the circumferential weld radiographs by the owner, it was concluded that linear indications were present in the welds. Using fracture mechanics procedures based on API 1104, we were able to conclude that the imperfections did not constitute a fracture risk. We also concluded that fatigue was not a life limiting condition.
Design Support - Offshore Pipeline Risk Analysis
APTECH was part of the Technology Development team for the proposed Oman-to-India natural gas pipeline. We were responsible for hazard scenario identification for all phases of the project (design, installation, and operation) and developed probabilistic risk assessments for the major hazard scenarios. The analyses resulted in a risk ranking of the key hazards based on realistic cost assessments of the consequences and evidence-based predictions of the likelihood. APTECH also contributed to issues related to fracture control, weld quality, pipeline collapse, and overall quality assurance programs.
Design Support - Alaskan Natural Gas Transmission System
In this project, APTECH provided design support for materials selection for the line pipe and compressor stations for the proposed transport of chilled natural gas. We developed the fracture control plan for the line pipe and welds and also used the result to tailor the inspection program and quality assurance plan. The reports on APTECH’s work were part of the submittal to a Federal Energy Regulatory Commission (FERC) for the project.
Natural Gas Line Collapse
In this project, APTECH analyzed the collapse of a buried natural gas line that was subjected to a shock wave from an explosion due to a fire at an ammonium perchlorate production plant. We calculate the forces imposed on the pipeline by the shock wave and also performed a condition assessment of the remaining section of the line. We also performed mechanical integrity calculations to determine if the gas line had leaked prior to the fire and explosion that was a hypothesis proposed by others for the failure scenario. We were able to demonstrate convincingly (to a jury) that the gas line damage was a result of the above ground explosion.
Onshore Pipeline Risk Analysis
APTECH developed risk analyses for
onshore lines as a means of ranking alternate
operating scenarios and for lines for which the local
environment has changed from swamp to flooded
conditions. We used DOT Office of Pipeline Safety
data to estimate the expected failure rate per mile
for the various operating scenarios. The data were
modified, based on specific line conditions to be
relevant to the situation analyzed. This project also
involved the evaluation of the corrosion control
program based on cathodic protection and coatings.
For an onshore oil pipeline and tank farm,
APTECH performed a risk and
reliability analysis to compare data from the USA
with data from East Europe. These data indicated much
higher incident rates and hence a higher risk when
the East European failure rates were used.