Gas–liquid flowing process in a horizontal well with premature liquid loading

Wang, Zhouhua; Fu, Xin; Guo, Ping; Tu, Hanmin; Wang, Hao; Zhong, Shichao

doi:10.1016/j.jngse.2015.05.003

Cited by 13 publications

(3 citation statements)

References 26 publications

(21 reference statements)

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“…The diameter of the bypass was 168 mm, and the delivery sequence was diesel oil pushing gasoline. When the volume fraction of gasoline in the dead-leg was less than 1%, we considered it to be completely replaced [32][33][34]. Figure 12 shows that the relationship between the length of the dead-leg and the time needed for the replacement of the dead-leg oil product can be described as: The gasoline was considered to be completely replaced by diesel oil when the volume percentage of gasoline in the dead-leg was less than 1% [30,31].…”

Section: The Effect Of the Dead-leg Length On Trailing Oilmentioning

confidence: 99%

Formation Mechanism of Trailing Oil in Product Oil Pipeline

Liu

Hong-jun

et al. 2018

Processes

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Trailing oil is the tail section of contamination in oil pipelines. It is generated in batch transportation, for which one fluid, such as diesel oil follows another fluid, such as gasoline, and it has an effect on the quality of oil. This paper describes our analysis of the formation mechanism of trailing oil in pipelines and our study of the influence of dead-legs on the formation of trailing oil. We found that the oil replacement rate in a dead-leg is exponentially related to the flow speed, and the length of the dead-leg is exponentially related to the replacement time of the oil. To reduce the amount of mixed oil, the main flow speed should be kept at about 1.6 m/s, and the length of the dead-leg should be less than five times the diameter of the main pipe. In our work, the Reynolds time-averaged method is used to simulate turbulence. To obtain contamination-related experimental data, computational fluid dynamics (CFD) software is used to simulate different flow rates and bypass lengths. MATLAB software was used to perform multi-nonlinear regression for the oil substitution time, the length of the bypass, and the flow speed. We determined an equation for calculating the length of the trailing oil contamination produced by the dead-leg. A modified equation for calculating the length of the contamination was obtained by combining the existing equation for calculating the length of the contamination with new factors based on our work. The amounts of contamination predicted by the new equation is closer to the actual contamination amounts than predicted values from other methods suggested by previous scholars.

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Section: The Effect Of the Dead-leg Length On Trailing Oilmentioning

confidence: 99%

Formation Mechanism of Trailing Oil in Product Oil Pipeline

Liu

Hong-jun

et al. 2018

Processes

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“…The diameter of the bypass was 168mm, and the delivery sequence was diesel oil pushing gasoline. When the volume fraction of gasoline in the dead-leg is less than 1%, we considered it to be completely replaced [31][32][33]. Figure 13 shows that when the length of the dead-leg is larger than 5 times of the main pipe diameter, the time required for the forward batch to be replaced by the backward batch in the deadleg increases sharply, which indicates that the effect of turbulent diffusion is still relatively large for this length.…”

Section: The Effect Of the Dead-leg Length On Trailing Oilmentioning

confidence: 99%

Research on Formation Mechanism of Trailing Oil in Product Oil Pipeline

Liu¹,

Li²,

Cai³

et al. 2018

Preprint

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Trailing oil is the tail section of contamination. There are two main reasons for the formation of trailing oil, one is the effect of laminar flow boundary layer, the other is the outflow of the preceding batch remained in the dead-legs. In the batch transportation of refined oil, under the action of viscous force, the preceding batch forms laminar boundary layer near the pipe wall and stays on the pipe wall, resulting in the phenomenon of contamination trailing and formation of trailing oil. When oil passes through the valve chamber of the oil transportation station, dead-leg will be formed. Due to gravity and convection diffusion, preceding batch flowing from dead-legs will form trailing oil in the pipeline. The phenomenon of trailing oil exists in the process of batch transportation, which will have an effect on the quality of oil. In this paper, Reynolds time-averaged method is used to simulate turbulence.Computational Fluid Dynamics(CFD) software is used to simulate different flow rates and bypass lengths to obtain contamination-related experimental data.Matlab software is used to perform multi-nonlinear regression for the oil substitution time, the length of the bypass and the flow rate. The formula for calculating the length of the trailing oil produced by the dead-leg is obtained. The modified formula for calculating the length of the contamination is obtained by combining the existing formula for calculating the length of the contamination.

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“…With the increasing demand for oil and natural gas resources, new technology in the field of oil and gas exploitation for efficiency improvement has been the focus for researchers home and abroad [1][2][3][4]. With the widely application of hydraulic fracturing in horizontal and highly deviated wells, the transportation of formation sand particles and fracturing proppant particles has aroused extensive interest for its great economic benefits and safety problems [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%