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- Title
高温定向井井筒瞬态温度计算模型及其应用.
- Authors
郑友志; 辜 涛; 舒 刚; 杨 谋; 余 江; 伍 葳; 张占武; 赵 军
- Abstract
The target layers of ultradeep natural gas wells in the western Sichuan Basin are at the depth about 8 000 m, the bottom hole original temperature is over 150 ℃, and the drilling mode of directional well is generally adopted here to drill to the target layers. In order to accurately predict the wellbore transient temperature in the drilling process of directional wells in the western Sichuan Basin and evaluate the influences of temperature environmental change on fluid performance and pressure distribution, this paper established a wellbore–formation two-dimensional transient heat transfer model of directional well and a wellbore pressure calculation model of temperature and pressure coupling on the basis of the momentum and energy conservation principles, combined with the characteristics of the directional wells in this area and the radial and axial heat transfer mechanisms in each region under the control of wellbore– formation. Then, this mathematical model was solved using the fully implicit finite difference method. Finally, the influences of circulation time and displacement on the wellbore temperature were analyzed, and the evolution characteristics of fluid density and pressure under temperature and pressure coupling were evaluated. And the following research results were obtained. First, as circulation time and displacement increase, the fluid temperature at the lower hole section and the formation temperature near the wellbore decrease and they are both lower than original formation temperature, while the fluid temperature at the upper section and the casing and cement sheath temperature near the wellbore are higher than the original formation temperature. Second, the wellbore circulation pressure, static density and equivalent circulating density under temperature and pressure coupling are lower than those without temperature and pressure conditions, and they are 2.1 MPa, 0.065 g/cm³ and 0.045 g/cm³, respectively. In conclusion, the research results can provide a reliable decision basis for analyzing the operational environment of directional drilling tools, evaluating the fluid performance in the full hole and controlling the wellbore pressure.
- Subjects
SICHUAN Sheng (China); GAS wells; DIRECTIONAL drilling; FINITE difference method; LOW temperatures; FLUID pressure; HEAT transfer fluids
- Publication
Natural Gas Industry, 2021, Vol 41, Issue 3, p119
- ISSN
1000-0976
- Publication type
Article
- DOI
10.3787/j.issn.1000-0976.2021.03.014