Heat Transfer in Tubing-Casing Annulus during Production Process of Geothermal Systems

In geothermal systems, the temperature distribution of heat flow in the wellbore is dependent on the well structure and the geological conditions of the surrounding formation. Understanding of heat transfer in the tubing-casing annulus can reduce the heat losses of wellbore fluid during the producti...

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Bibliographic Details
Published inJournal of earth science (Wuhan, China) Vol. 26; no. 1; pp. 116 - 123
Main Authors Zhou, Fuzong, Zheng, Xiuhua
Format Journal Article
LanguageEnglish
Published Heidelberg China University of Geosciences 01.02.2015
Springer Nature B.V
Department of Economics and Management, Tongren University, Tongren 554300, China%School of Engineering and Technology, China University of Geosciences, Beijing 100083, China
Subjects
Biogeosciences
Conductivity
Earth and Environmental Science
Earth science
Earth Sciences
Emissivity
Fluid dynamics
Fluid flow
Fluids
Geochemistry
Geology
Geophysics
Geotechnical Engineering & Applied Earth Sciences
Geothermal
Heat flow
Heat transfer
Mathematical analysis
Radiation
Special Issue on Geohtermal Energy
Temperature distribution
Thermal conductivity
Thermal radiation
Well drilling
传热
地热系统
套管
油管
热传递系数
环形空间
环空
生产过程
tubing-casing annulus
radiation
natural convection
Rayleigh number
geothermal system
thermal conductivity
heat transfer
geo-thermal system
Online AccessGet full text
ISSN1674-487X
1867-111X
DOI10.1007/s12583-015-0511-5

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Summary:In geothermal systems, the temperature distribution of heat flow in the wellbore is dependent on the well structure and the geological conditions of the surrounding formation. Understanding of heat transfer in the tubing-casing annulus can reduce the heat losses of wellbore fluid during the production process. The present study discusses the possible means of heat transfer in the annulus, and develops a piecewise equation for estimating the convective heat transfer coefficient with a wider valid condition of 0〈Ra〈7.17×10^8. By converting the radiation and natural convection into equivalent thermal conduction, their sum is defined as a total thermal conductivity to describe the heat transfer in the annulus. The results indicate that the annulus filled with gas can be utilized as a good thermal barrier for the fluid in the wellbore. Additionally, the contribution of radiation will increase to occupy a majority proportion in the total thermal conductivity when the annular size increases and the materials have high emissivity. Otherwise, thermal radiation is just the second factor.
Bibliography:In geothermal systems, the temperature distribution of heat flow in the wellbore is dependent on the well structure and the geological conditions of the surrounding formation. Understanding of heat transfer in the tubing-casing annulus can reduce the heat losses of wellbore fluid during the production process. The present study discusses the possible means of heat transfer in the annulus, and develops a piecewise equation for estimating the convective heat transfer coefficient with a wider valid condition of 0〈Ra〈7.17×10^8. By converting the radiation and natural convection into equivalent thermal conduction, their sum is defined as a total thermal conductivity to describe the heat transfer in the annulus. The results indicate that the annulus filled with gas can be utilized as a good thermal barrier for the fluid in the wellbore. Additionally, the contribution of radiation will increase to occupy a majority proportion in the total thermal conductivity when the annular size increases and the materials have high emissivity. Otherwise, thermal radiation is just the second factor.
42-1788/P
heat transfer, tubing-casing annulus, Rayleigh number, natural convection, geothermal system, thermal conductivity, radiation.
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ISSN:1674-487X
1867-111X
DOI:10.1007/s12583-015-0511-5