Enbridge Northern Pipeline: 25 Years of Operation, Successes and Challenges

2010 ◽  
Author(s):  
Ingrid Pederson ◽  
Millan Sen ◽  
Andrew Bidwell ◽  
Nader Yoosef-Ghodsi
Keyword(s):  
Crude Oil ◽  
Ground Movement ◽  
Oil Pipeline ◽  
Ground Temperatures ◽  
Geotechnical Monitoring ◽  
Discontinuous Permafrost ◽  
Long Term Trends ◽  
Slope Instabilities ◽  
Successes And Challenges

Enbridge Pipelines Inc. has operated a 324 mm diameter, 870 km crude oil pipeline from Norman Wells, Northwest Territories to Zama, Alberta since 1985. This pipeline is the first completely buried oil pipeline constructed within the discontinuous permafrost zone of Canada. This pipeline was constructed over two winter seasons, and since 1985 has transported roughly 200 million barrels of crude oil to southern markets without significant interruption. This paper will review the design, construction, and operational challenges of this pipeline through the past 25 years. Unique and innovative aspects of this pipeline include measures taken during construction to minimize thermal disturbance to the soil, insulating permafrost slopes to minimize post-construction thaw, operating at temperatures that minimize thermal effects on the surrounding ground, accommodating ground movement caused by frost heave/thaw and slope instabilities, and evaluating the effects of moving water bodies adjacent to the pipeline right-of-way. The use of in-line inspection tools (GEOPIG) has been valuable as a supplement to conventional geotechnical monitoring, for the evaluation and assessment the effects of ground movement to the pipeline. Finite element pipe/soil interaction models have been developed for selected sites in order to assess the potential for slope movement to generate strains in the buried pipeline that exceed the strain capacity. This paper will review new monitoring data and findings since previous publications. In addition, the implications of long-term trends of increasing ground temperatures and associated changes to the geotechnical and permafrost conditions along the pipeline route will also be discussed and are relevant to other proposed pipeline and linear infrastructure projects along the Mackenzie Valley.

Permafrost Hazard of MoHe-DaQing Crude Oil Pipeline

2013 ◽  
Vol 734-737 ◽  
pp. 2659-2663
Author(s):  
Yun Bin Ma ◽  
Dong Jie Tan ◽  
Hong Yuan Jing ◽  
Quan Xue ◽  
Cheng Zhi Zhang
Keyword(s):  
Crude Oil ◽  
The Other ◽  
Frost Heave ◽  
Permafrost Soil ◽  
Buried Pipeline ◽  
Soil Frost ◽  
Plastic Deformations ◽  
Oil Pipeline ◽  
Thaw Settlement ◽  
Slope Instabilities

The crude oil pipeline from MoHe to DaQing (hereafter called Mo-Da pipeline) is part of China-Russia oil pipeline. Mo-Da pipeline is the first pipeline that through high latitude cold regions of China. The pipeline is in so complicated geography environment that many kinds of permafrost hazard are easily to happen including frost heave, thaw settlement, slope instabilities, and collapse and so on. The pipeline and the permafrost act and react upon one another. On one hand, soil frost heave and thaw settlement can produce extra stresses on pipe walls, which may result in centralized stresses and plastic deformations under certain conditions, even causes pipeline faults. On the other hand, buried pipeline will disturb ambient environment and then degrade the permafrost soil and finally impact safety of the pipeline. This paper mainly introduces the permafrost hazards of Mo-Da pipeline and demonstrates some methods for monitoring the influence of permafrost.

A Model for Predicting the Average Hydraulic Wax Deposition Thickness of a Long-Term Unpigged Crude Pipeline

2010 ◽  
Author(s):  
Qing Miao ◽  
Baoliang Jiang ◽  
Jianghua Tao ◽  
Sen Hu ◽  
Jianjun Liu
Keyword(s):  
Mathematical Model ◽  
Crude Oil ◽  
Wax Deposition ◽  
Oil Pipeline ◽  
Deposition Thickness ◽  
Northeast Of China ◽  
Statistical Results

A crude oil pipeline transporting Daqing crude in the Northeast of China had not been carried out pigging for four years. The wax deposition in it increased gradually over past four years. In this paper, from the operation data of the pipeline among the four years, the average hydraulic wax deposition thicknesses are calculated and analyzed statistically. Based on the results, the increment of the wax deposition in the long-term unpigged crude oil pipeline is concluded qualitatively and so a mathematical model for predicting the average hydraulic wax deposition thickness of such a pipeline is created. The physical meanings of the coefficients in the model are explained in the paper. Also, as an example for showing how to use this model, the statistical results on certain section of the pipeline are selected and the determination for the coefficients is introduced in detail.

Guidelines to Develop Fitness-for-Service Assessments in Oil Pipelines Exposed to Corrosive and Geotechnical Environments

2004 ◽  
Author(s):  
Rafael G. Mora ◽  
Carlos Vergara ◽  
Guy Krepps
Keyword(s):  
Crude Oil ◽  
Phase 1 ◽  
Growth Modeling ◽  
Internal Corrosion ◽  
Oil Pipeline ◽  
Maintenance Program ◽  
Integrity Management ◽  
Near Term ◽  
Term Maintenance

Industry standards (i.e. API 1160, ASME B31.4 and B31.8S-2001, CSA-Z662-2003) and regulations (i.e. US DOT 49 Parts 195-2002 and 192-2003, and NEB On-shore 99) have delineated the risk-based elements of oil and gas pipeline integrity management programs. A Fitness-For-Service Assessment is part of an overall Integrity Management Program that is implemented for the pipeline system depending on the required pipeline operational conditions, severity of integrity threats, and their impact or consequences to the public, environment and employees. This paper provides guidelines for pipeline operators of oil pipeline systems exposed to corrosive and geotechnical sensitive environments and high consequence areas to develop long term integrity plans. In this case, the pipeline integrity plans were prepared based on the integration of data and assessments such as metal loss, geometry and strain in-line inspections, product corrositivity, cathodic protection, geotechnical hazard identification, and pipe class location/high consequence areas. Guidelines for developing near-term integrity plans are herein provided based on best industry practices and regulations. In 2002, Oleoducto Central S.A. (Ocensa) and CC Technologies initiated the Phase 1 of the Fitness-for-Service assessment of 698 km of NPS 16/30 crude oil pipeline from Cupiagua to Coven˜as. Phase 1 was comprised of an internal corrosion study to assess the corrosivity of the product and its impact in the future. Corrosivity of the crude oil was determined from laboratory testing and correlated to the pipeline operational and topographical conditions. In 2003, the Phase 2 of the Fitness-for-Service assessment was comprised of a review of the near-term maintenance program and the development of the long-term maintenance program. The long-term integrity plan program for corrosion features was developed using a deterministic and probabilistic corrosion growth modeling to determine excavation/repair and re-inspection interval alternatives. The corrosion growth modeling took into account the in-line inspection tool accuracy based on the field validation program. The most cost effective alternative was identified by using a cost benefit analysis technique. This implemented approach contributed to timely schedule maintenance activities. In addition, the selected excavations confirmed with high confidence the results from the Ocensa-CC Technologies Canada predictability model. Geometry features reported by the geometry/inertial in-line inspection were initially evaluated, and correlated to the corrosion in-line inspection data, and the geotechnical hazard study to identify potential locations of slope instability, river-crossing scouring for assessing internal corrosion criticality. Strain areas were also assessed and correlated to pipe wall deformation and potential areas of land movement. Pipe class location limits were determined based on latest dwelling locations and distribution, and then correlated to the reported corrosion features for verifying minimum safety factors. The long-term maintenance program was integrated from all assessments performed on the identified integrity threats. As a result, guidelines were prepared for implementing technically sound and economically-optimized long-term inline inspection, excavation and repair plans.

Study on the Safety of Restart of a Long-Term Unpigged Crude Pipeline

2010 ◽  
Author(s):  
Qing Miao
Keyword(s):  
Numerical Simulation ◽  
Crude Oil ◽  
Heat Loss ◽  
Paper Study ◽  
Wax Deposition ◽  
Oil Pipeline ◽  
Heat Preservation ◽  
Northeast Of China

A crude oil pipeline transporting heated Daqing crude in the Northeast of China had not carried out pigging for four years and the wax deposition in it was very serious. The existence of wax deposition layer decreased the heat loss of the crude in the pipeline during its normal running, but this did not mean it would also make the pipeline cool down slowly after the shutdown of the pipeline, that is, the wax deposition does not always benefit to the heat preservation of a long-term unpigged hot crude pipeline. So the restart safety of a long-term unpigged hot crude pipeline could not be derived directly from that of the same pipeline pigged before shutdown, even qualitatively. In this paper, study on the safety of the restart of a long-term unpigged crude pipeline is conducted based on numerical simulation and significant conclusions are drawn.

Commercial trawling in seagrass beds: bycatch and long-term trends in effort of a major shrimp fishery

2014 ◽  
Vol 513 ◽  
pp. 143-153 ◽  
Author(s):  
CD Stallings ◽  
JP Brower ◽  
JM Heinlein Loch ◽  
A Mickle
Keyword(s):  
Seagrass Beds ◽  
Shrimp Fishery ◽  
Long Term Trends
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