scholarly journals FLOW ASSURANCE IN KUMUJE WET-GAS PIPELINE: ANALYSIS OF PIGGING SOLUTION TO LIQUID ACCUMULATION

2018 ◽  
Vol 9 (9) ◽  
pp. 380-386
Author(s):  
Sarah Akintola ◽  
Emmanuel Folorunsho ◽  
Oluwakunle Ogunsakin
Keyword(s):  
Pressure Loss ◽  
Gas Pipeline ◽  
Gas Condensate ◽  
Flow Assurance ◽  
Gas Pipelines ◽  
Wet Gas ◽  
Highly Sensitive ◽  
Temperature And Pressure ◽  
Pipeline Corrosion ◽  
Assurance Problem

Liquid condensation in gas-condensate pipelines in a pronounced phenomenon in long transporting lines because of the composition of the gas which is highly sensitive to variations in temperature and pressure along the length of the pipeline. Hence, there is a resultant liquid accumulation in onshore wet-gas pipelines because of the pipeline profile. This accumulation which is a flow assurance problem can result to pressure loss, slugging and accelerated pipeline corrosion if not properly handled.

Flow Assurance in Deep-Water Gas Pipelines: Locating Hydrate Plugging Position in a Fast Way

2021 ◽  
Author(s):  
Jing Yu ◽  
Cheng Hui ◽  
Chao Wen Sun ◽  
Zhan Ling Zou ◽  
Bin Lu Zhuo ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Deep Water ◽  
Pipe Wall ◽  
Gas Pipeline ◽  
Flow Assurance ◽  
Gas Pipelines ◽  
Long Distance ◽  
Hydrate Layer ◽  
Hydrate Deposition ◽  
Water Gas

Abstract Hydrate-associated issues are of great significance to the oil and gas sector when advancing the development of offshore reservoir. Gas hydrate is easy to form under the condition featuring depressed temperature and elevated pressure within deep-water gas pipeline. Once hydrate deposition is formed within the pipelines, the energy transmission efficiency will be greatly reduced. An accurate prediction of hydrate-obstruction-development behavior will assist flow-assurance engineers to cultivate resource-conserving and environment-friendly strategies for managing hydrate. Based on the long-distance transportation characteristics of deep-water gas pipeline, a quantitative prediction method is expected to explain the hydrate-obstruction-formation behavior in deep-water gas pipeline throughout the production of deep-water gas well. Through a deep analysis of the features of hydrate shaping and precipitation at various locations inside the system, the advised method can quantitatively foresee the dangerous position and intensity of hydrate obstruction. The time from the start of production to the dramatic change of pressure drop brought about by the deposition of hydrate attached to the pipe wall is defined as the Hydrate Plugging Alarm Window (HPAW), which provides guidance for the subsequent hydrate treatment. Case study of deep-water gas pipeline constructed in the South China Sea is performed with the advised method. The simulation outcomes show that hydrates shape and deposit along pipe wall, constructing an endlessly and inconsistently developing hydrate layer, which restricts the pipe, raises the pressure drop, and ultimately leads to obstruction. At the area of 700m-3200m away from the pipeline inlet, the hydrate layer develops all the more swiftly, which points to the region of high risk of obstruction. As the gas-flow rate increases, the period needed for the system to shape hydrate obstruction becomes less. The narrower the internal diameter of the pipeline is, the more severe risk of hydrate obstruction will occur. The HPAW is 100 days under the case conditions. As the concentration of hydrate inhibitor rises, the region inside the system that tallies with the hydrate phase equilibrium conditions progressively reduces and the hydrate deposition rate slows down. The advised method will support operators to define the location of hydrate inhibitor injection within a shorter period in comparison to the conventional method. This work will deliver key instructions for locating the hydrate plugging position in a fast way in addition to solving the problem of hydrate flow assurance in deep-water gas pipelines at a reduced cost.

Comparison of PIR to PIPESAFE-Based 1% Lethality Zones for Natural Gas Pipelines

2014 ◽  
Author(s):  
Aleksandar Tomic ◽  
Shahani Kariyawasam
Keyword(s):  
Natural Gas ◽  
Small Diameter ◽  
Gas Pipeline ◽  
Accurate Estimation ◽  
Simple Relationship ◽  
Gas Pipelines ◽  
Friction Forces ◽  
Natural Gas Pipelines ◽  
Decay Factor ◽  
Outflow Rate

A lethality zone due to an ignited natural gas release is often used to characterize the consequences of a pipeline rupture. A 1% lethality zone defines a zone where the lethality to a human is greater than or equal to 1%. The boundary of the zone is defined by the distance (from the point of rupture) at which the probability of lethality is 1%. Currently in the gas pipeline industry, the most detailed and validated method for calculating this zone is embodied in the PIPESAFE software. PIPESAFE is a software tool developed by a joint industry group for undertaking quantitative risk assessments of natural gas pipelines. PIPESAFE consequence models have been verified in laboratory experiments, full scale tests, and actual failures, and have been extensively used over the past 10–15 years for quantitative risk calculations. The primary advantage of using PIPESAFE is it allows for accurate estimation of the likelihood of lethality inside the impacted zone (i.e. receptors such as structures closer to the failure are subject to appropriately higher lethality percentages). Potential Impact Radius (PIR) is defined as the zone in which the extent of property damage and serious or fatal injury would be expected to be significant. It corresponds to the 1% lethality zone for a natural gas pipeline of a certain diameter and pressure when thermal radiation and exposure are taken into account. PIR is one of the two methods used to identify HCAs in US (49 CFR 192.903). Since PIR is a widely used parameter and given that it can be interpreted to delineate a 1% lethality zone, it is important to understand how PIR compares to the more accurate estimation of the lethality zones for different diameters and operating pressures. In previous internal studies, it was found that PIR, when compared to the more detailed measures of the 1% lethality zone, could be highly conservative. This conservatism could be beneficial from a safety perspective, however it is adding additional costs and reducing the efficiency of the integrity management process. Therefore, the goal of this study is to determine when PIR is overly conservative and to determine a way to address this conservatism. In order to assess its accuracy, PIR was compared to a more accurate measure of the 1% lethality zone, calculated by PIPESAFE, for a range of different operating pressures and line diameters. Upon comparison of the distances calculated through the application of PIR and PIPESAFE, it was observed that for large diameters pipelines the distances calculated by PIR are slightly conservative, and that this conservativeness increases exponentially for smaller diameter lines. The explanation for the conservatism of the PIR for small diameter pipelines is the higher wall friction forces per volume transported in smaller diameter lines. When these higher friction forces are not accounted for it leads to overestimation of the effective outflow rate (a product of the initial flow rate and the decay factor) which subsequently leads to the overestimation of the impact radius. Since the effective outflow rate is a function of both line pressure and diameter, a simple relationship is proposed to make the decay factor a function of these two variables to correct the excess conservatism for small diameter pipelines.

METHODOLOGICAL ASPECT OF ASSESSING RELIABILITY OF MEDIUM PRESSURE GAS PIPELINES

2021 ◽  
pp. 97-107
Author(s):  
A.I. Pashentsev ◽  
A.A. Garmider
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Methodological Approach ◽  
Gas Pipeline ◽  
Methodological Aspect ◽  
Gas Pipelines ◽  
Gas Flow Rate ◽  
Medium Pressure ◽  
Reliability Calculation

The author’s vision of the methodological aspect of assessing the reliability of medium pressure gas pipelines is presented. Analysis of existing methods for assessing the reliability of gas pipelines with the identification of positive and negative features was carried out, a methodological approach to assessing the reliability of medium pressure gas pipelines by gas flow rate and pressure was developed and tested, and a scale for identifying the results of reliability calculation was developed. The test conducted on the example of a really working gas pipeline with a test for reliability showed its promise.

Advances in Abandonment and Disposal Technology of Aging Oil and Gas Pipelines

2021 ◽  
Author(s):  
Jiaqiang Jing ◽  
Wenlu Wang ◽  
Dongrong Wu ◽  
Jinhua Luo ◽  
Shuang Zeng ◽  
...  
Keyword(s):  
Environmental Protection ◽  
Oil And Gas ◽  
Residual Life ◽  
Practical Experience ◽  
Gas Pipeline ◽  
Practical Significance ◽  
Systematic Evaluation ◽  
Gas Pipelines ◽  
Oil And Gas Pipelines ◽  
The Status

Abstract When the operation benefit of an oil and gas pipeline is not enough to cover its operation cost, and the pipeline is no alternative use, seriously damaged, aged or the operation risk exceeds the acceptable range, it is bound to cause serious safety and environmental hazards along the pipeline, especially for the over age pipeline in service, therefore its scientific abandonment and reasonable disposal is particularly important and urgent. Focused on the methods for judging abandonment, retirement modes, cleaning and environmental management of oil and gas pipelines, the characteristics of existing methods for predicting the remaining life of the pipelines and their application in abandonment and disposal are compared and analyzed, and the basis and adaptability of oil and gas pipelines retirement are illuminated. According to the actual situation and environment of the discarded pipelines, the selection basis and applicable conditions of the pipeline and facility disposal methods such as demolition, in-situ shelving and their combination are expounded. It is found that North America has rich experience and mature technology in oil and gas pipeline abandonment and disposal, but many countries, including China, seriously lack scientific and systematic evaluation standards, practical experience, related theoretical and technical investigations. This study has important reference and practical significance for promoting the development of abandonment and disposal technology of an aging oil and gas pipeline, and ensuring the personal safety and ecological environmental protection along the abandoned pipeline. This paper presents the status quo of over age service and abandonment decision-making of oil and gas pipelines in the world, draws lessons from the experience of safety and environmental protection disposal of the global abandoned pipelines, and puts forward the principle and method of abandonment judgment and scientific disposal of the aging pipelines based on residual life evaluation. This method has sufficient basis, strong adaptability and wide application.

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