An annular fluid comprehensive friction coefficient determination method and device
A friction coefficient and determination method technology, applied in electrical digital data processing, special data processing applications, instruments, etc., can solve problems such as inaccurate calculation of friction coefficient of annular fluid
Active Publication Date: 2019-05-03
YANGTZE UNIVERSITY
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[0004] The present invention proposes a method and device for determining the comprehensive friction coefficient of annular fluid based on the diameter enlargement ratio, so as to solve the problem of inaccurate calculation of the friction coefficient of annular fluid in irregular boreholes
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[0028] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings and experimental data.
[0029] See figure 1 , the present invention proposes a method for determining the comprehensive friction coefficient of annular fluid, said method comprising:
[0030] S1. Obtain the outer diameter D of the drill string in the current drilling of the wellbore po , drill string inner diameter D pi , diameter series data of open hole section, drilling fluid density ρ d , common drilling fluid circulation displacement Q k , k=1,2,...,m, m is the number of commonly used drilling fluid circulation displacements, and the inner diameter of the last casing D ci , length L 0 ; The open-hole section caliper series data includes the logging section length L j , diameter D j , diameter enlargement...
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The invention discloses a method and a device for determining the comprehensive friction coefficient of an annulus fluid. The method comprises the following steps of: acquiring borehole drilling string data, open hole section well diameter series data, drilling fluid data and the inner diameter and length of a previous casing pipe; combining and classifying the well diameter series data of the open hole section, and combining well sections with the well diameter expansion rate difference within a preset deviation range into one section; starting the drilling pump to circulate the slurry with the common drilling fluid discharge capacity when the drilling column descends to the bottom of the well, and establishing a wellhead pressure calculation equation; searching u + 1 wells which are thesame as the borehole geological condition, the well body structure, the well body mass, the drilling fluid performance and the drill string structure in the same block, establishing u + 1 wellhead pressure calculation equations according to the same method, and solving the algebraic equation set by adopting a Jacobian iteration method; and performing curve fitting to obtain annulus fluid comprehensive friction coefficients corresponding to the borehole diameter enlargement rates under different circulation displacement conditions. According to the method, the calculation accuracy of the friction coefficient of the annulus fluid can be improved.
Description
technical field [0001] The invention belongs to the technical field of petroleum engineering drilling, and in particular relates to a method and a device for determining the comprehensive friction coefficient of annular fluid. Background technique [0002] During the drilling process, due to the impact of formation fragmentation and heterogeneity, the expansion of well diameter is very common, and the surface of the well wall is irregular. Sometimes the expansion is uneven and unconventional wells such as "big belly" or "sugar haws" are formed. Eye. When the fluid flows in the annulus, diameter expansion and irregular borehole walls will affect the flow friction in the annulus, thereby affecting the pressure profile of the annulus. For formations with a narrow density window, if the calculation is inaccurate, it is easy to cause well kick and lost circulation Wait for an accident. Therefore, it is very important to accurately calculate the friction coefficient of annular f...
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IPC IPC(8): G06F17/50
CPCY02T90/00
Inventor 郑双进吴红建黄鹏熊冬
Owner YANGTZE UNIVERSITY