Pipeline Trenching in Permafrost: A Review

2002 ◽  
Author(s):  
Denis Blanchet ◽  
Nick Lenstra ◽  
John Skalski ◽  
Joe Zhou ◽  
Bruce Smith
Keyword(s):  
Tensile Strength ◽  
Oil And Gas ◽  
Large Diameter ◽  
Field Trials ◽  
Permafrost Soil ◽  
Case Histories ◽  
Construction Costs ◽  
Long Distance ◽  
Current Technology ◽  
Oil And Gas Pipelines

BP America Inc., Enbridge Pipelines Inc., and TransCanada PipeLines Limited recently sponsored a comprehensive technical review of the use of wheel and chain trenchers for excavating pipeline ditches for large diameter, long distance oil and gas pipelines in permafrost. The purpose of the review was to identify techniques that could be implemented to improve the productivity of trenchers in permafrost and reduce pipeline construction costs. This paper summarizes the key findings of the study. The study included an analysis of data obtained from previous field trials and construction case histories in permafrost, including the results from proprietary trials that have never been published. The study found that the primary subsurface conditions affecting the productivity of both wheel and chain trenchers in permafrost soil are: 1) the concentration and lithology of cobbles and boulders; 2) the presence and strength of bedrock within the depth of trenching; and 3) the tensile strength of the permafrost soil. With current technology, neither wheel nor chain trenchers can achieve satisfactory rates of production if more than 5 to 10 percent cobbles or boulders are present, or if hard bedrock exists within the depth of trenching. The study evaluated a number of techniques for improving the productivity of both wheel and chain trenchers in permafrost soil which may or may not contain hard inclusions. These methods included pre-blasting along the ditchline using either conventional blasting techniques or shaped charges. In addition, a wide variety of multi-pass trenching techniques were evaluated as part of the study.

A Justification for Designing and Operating Pipelines Up to Stresses of 80% SMYS

2002 ◽  
Author(s):  
Martin McLamb ◽  
Phil Hopkins ◽  
Mark Marley ◽  
Maher Nessim
Keyword(s):  
Yield Strength ◽  
Oil And Gas ◽  
Large Diameter ◽  
Pipe Material ◽  
Gas Pipelines ◽  
Long Distance ◽  
Remote Locations ◽  
Pass Through ◽  
The Impact ◽  
Minimum Yield

Oil and gas majors are interested in several projects worldwide involving large diameter, long distance gas pipelines that pass through remote locations. Consequently, the majors are investigating the feasibility of operating pipelines of this type at stress levels up to and including 80% of the specified minimum yield strength (SMYS) of the pipe material. This paper summarises a study to investigate the impact upon safety, reliability and integrity of designing and operating pipelines to stresses up to 80% SMYS.

scholarly journals Pipeline Bending Strain Measurement and Compensation Technology Based on Wavelet Neural Network

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Rui Li ◽  
Maolin Cai ◽  
Yan Shi ◽  
Qingshan Feng ◽  
Shucong Liu ◽  
...  
Keyword(s):  
Neural Network ◽  
Oil And Gas ◽  
Original Method ◽  
Wavelet Neural Network ◽  
Measurement Unit ◽  
Gas Pipelines ◽  
Long Distance ◽  
Pipeline Inspection ◽  
Bending Strain ◽  
Oil And Gas Pipelines

The bending strain of long distance oil and gas pipelines may lead to instability of the pipeline and failure of materials, which seriously deteriorates the transportation security of oil and gas. To locate the position of the bending strain for maintenance, an Inertial Measurement Unit (IMU) is usually adopted in a Pipeline Inspection Gauge (PIG). The attitude data of the IMU is usually acquired to calculate the bending strain in the pipe. However, because of the vibrations in the pipeline and other system noises, the resulting bending strain calculations may be incorrect. To improve the measurement precision, a method, based on wavelet neural network, was proposed. To test the proposed method experimentally, a PIG with the proposed method is used to detect a straight pipeline. It can be obtained that the proposed method has a better repeatability and convergence than the original method. Furthermore, the new method is more accurate than the original method and the accuracy of bending strain is raised by about 23% compared to original method. This paper provides a novel method for precisely inspecting bending strain of long distance oil and gas pipelines and lays a foundation for improving the precision of inspection of bending strain of long distance oil and gas pipelines.

scholarly journals Optimization of distribution of emergency resources for emergency rescue points of oil and gas pipelines

2021 ◽  
Vol 266 ◽  
pp. 01016
Author(s):  
Y.Y. Chen ◽  
L.B. Zhang ◽  
J.Q. Hu ◽  
Z.Y. Liu
Keyword(s):  
Resource Allocation ◽  
Oil And Gas ◽  
Resources Allocation ◽  
Gas Pipelines ◽  
Long Distance ◽  
Emergency Rescue ◽  
Oil And Gas Pipelines ◽  
Fixed Proportion ◽  
Optimized Allocation ◽  
Resource Shortage

According to the inherent characteristics of long-distance oil and gas pipelines, the optimization of emergency resources allocation can be implemented to maximize the utilization of pipeline emergency resources under a certain cost of emergency investment. We built an improved solution of a multiple knapsack problem in a greedy algorithm, proposed maximizing Emergency Resources Factor (ERF) as the greedy strategy, and established the optimization model of emergency resources allocation. This model innovatively combines factors such as the centrality of rescue points, the risk of pipe sections, and the necessity of emergency resources. The results show that, compared to a conventional resource allocation in a fixed proportion, an optimized allocation can reduce resource shortage and redundancy by 2.660% and 1.051%, respectively. Therefore, this model can be used to control the initialization of resource allocation in emergency rescue points of long-distance oil and gas pipelines.

Field Trials of Suction-Assisted Installation of Circular Steel Pipe Cofferdam in Silty Sand

2020 ◽  
Author(s):  
Jae-Hyun Kim ◽  
Zhenhua Xin ◽  
Ju-Hyung Lee
Keyword(s):  
Large Diameter ◽  
Test Site ◽  
Field Trials ◽  
Offshore Structures ◽  
Silty Sand ◽  
Steel Pipe ◽  
Sheet Pile ◽  
Construction Costs ◽  
Inner Diameter ◽  
Column Foundation

Abstract The cofferdam is the temporary barrier to stop the flow of water from a construction site work such as a support column foundation at a river or offshore. It allows for working in the dry condition when the construction is done adjacent or within the waters. However, it is a major cause of delays and increased construction costs because additional works are required to stop the water flow. Recently, in order to overcome the limitations of the conventional cofferdam methods such as sheet pile or caisson tube cofferdams, a large-diameter steel pipe cofferdam method has been proposed which can be installed quickly using suction installation method. The steel pipe cofferdam method is characterized in that the top-lid of the steel pipe is located above the sea level in order to use it as a water barrier, unlike conventional suction buckets where the whole structures are submerged. In this study, the circular steel pipe cofferdam with a 5 m inner diameter was fabricated and the installation tests were conducted on silty sand at the Saemaguem test site. During the experiment, variations of suction pressure and inclination of the steel pipe cofferdam were measured and post-analyzed. This study verified the new steel pipe cofferdam method and confirmed that the suction installation method can be successfully used for various purposes on the offshore structures.

Study on the Weldability of X100 Pipeline Steel on Scene

2013 ◽  
Vol 753-755 ◽  
pp. 343-352
Author(s):  
Pin Yi Wang ◽  
Zong Yuan Mou
Keyword(s):  
Oil And Gas ◽  
Pipeline Steel ◽  
Large Diameter ◽  
Welding Process ◽  
Field Application ◽  
Organization Performance ◽  
Long Distance ◽  
Line Pipe ◽  
Pipe Welding ◽  
X100 Pipeline Steel

With the long-distance oil and gas pipelines are to development of the direction of large-diameter, high-pressure, high grade pipeline steel applications gradually become the trend of the development of the oil and gas pipeline construction. The welding process of the X100 line pipe which is about to industrial application is not yet to be determined. It is not clear that the affect to the weldability from the metallurgical composition, organization, performance, and other factors which would affect the site construction welding process and welding measures. In addition, it is not yet the discussion and analysis of the key technologies X100 line pipe-site welding process and defect types. In this paper, the X100 pipeline on-site application of welding technology research commenced work and studied the weldability and welding process of X100 which solve the field application of X100 pipeline steel pipe welding issues.

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