Method for calculating spiral flow velocity of Newtonian fluid eccentric annuli
A technology of eccentric annular space and spiral flow, which is applied in the directions of fluid velocity measurement, fluid dynamics test, velocity/acceleration/impact measurement, etc. It can solve the problems of not reaching the application level and complicated results, and achieve the effect of improving calculation accuracy
Inactive Publication Date: 2009-09-09
CHINA NAT OFFSHORE OIL CORP +1
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Problems solved by technology
In the existing method, the complex variable function method is used to map the eccentric ring to the bipolar coordinates, and the analytical solution of the axial flow of the Newtonian liquid laminar flow in the eccentric ring space is obtained, and the result is very complicated
In recent years, although some scholars have made some improvements to the analysis method of Newtonian fluid eccentric annulus spiral flow, it is far from being applied.
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[0015] The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.
[0016] Such as figure 1 , during the drilling process, the inner pipe 1 is the drill string, the outer pipe 2 is the wellbore, and the middle space between the inner pipe 1 and the outer pipe 2 is the annular space. The outer cylindrical surface of the inner tube 1 is S a , the inner cylindrical surface of the outer tube 2 is S b ;The axial length of the annular space is L, that is, the drilling depth; the two cylindrical surfaces S a and S b The distance between is the clearance of the eccentric annulus, denoted by h. In the actual working conditions of oil drilling, since the axial length L of the annular space is much larger than the gap h of the eccentric annular space, that is, h / La As the base surface, an S-family coordinate system (x α , x 3 ), where x α is the outer cylindrical surface S of the inner tube 1 a Gaussian coordinates on , ...
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A method for calculating spiral flow velocity of Newtonian fluid eccentric annuli is characterized in that an analytical method is adopted for calculating the spiral flow field of eccentric annuli; the three-dimensional spiral flow is simplified to the two-dimensional flow in the thin layer of annuli through mapping the momentum tensor equation of Newtonian fluid in the three-dimensional Euclidean space into the two-dimensional space of Riemann surface, and finally the analytic solution of spiral flow velocity of Newtonian fluid eccentric annuli, which is concisely expressed, is obtained. The analytic solution of spiral flow velocity of Newtonian fluid eccentric annuli of the invention can be used for predicting and quantizing the problems of cement top between the wide-clearance cement slurry and narrow-clearance cement slurry and slury channeling in the two-phase flow when the oil drilling slurry replaces the cement slurry. The method of the invention has important practical significance in researching the cuttings-carrying flow regulation of annuli of oil well-drilling project, calculating the course flow resistance of wellhead annuli and increasing the calculating accuracy.
Description
technical field [0001] The invention relates to a method for measuring and calculating Newtonian fluid, in particular to a method for calculating the velocity of spiral flow in eccentric annular space of Newtonian fluid. Background technique [0002] Discrimination and research of annular fluid state in eccentric circular pipes have always been the basic research content of annular hydraulics in petroleum drilling engineering. In the drilling operations of highly deviated wells and horizontal wells, the inner pipe sinks due to gravity to form an eccentric annular channel. When the drilling mud and cement slurry fluid carrying rock flow in this channel, due to the uneven distribution of the flow field, the The low position of the narrow side is easy to make the cuttings and solid phase particles in the mud and cement slurry settle to the narrow side, resulting in the accumulation of cuttings on the narrow side and hindering the smooth passage of the annulus. Therefore, it is...
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IPC IPC(8): G01P5/00G01M10/00E21B49/00E21B47/00
CPCE21B33/14E21B47/0005E21B47/005
Inventor 蒋世全姜伟牛海峰
Owner CHINA NAT OFFSHORE OIL CORP