Numerical Analysis of Pressure Gradient along Casing in Helical Turbulent Flow of Power Law Fluid in Eccentric Annulus

2012 ◽  
Vol 616-618 ◽  
pp. 685-689
Author(s):  
Zheng Li ◽  
Hong Wu Zhu ◽  
Xiao Li Fan ◽  
Jian Sheng Hao ◽  
Xiang Ling Kong
Keyword(s):  
Angular Velocity ◽  
Pressure Gradient ◽  
Flow Velocity ◽  
Power Law ◽  
Annular Flow ◽  
Drilling Fluid ◽  
Average Pressure ◽  
Power Law Fluid ◽  
Pipe Length ◽  
Average Pressure Gradient

With the use of casing running tool (CRT), casing can be rotated and reciprocated at the same time with circulation of drilling fluid. Thus the flow in well bore was eccentric annular helical. Pressure exerted on casing was important for casing buckling analysis. A numerical model of eccentric annular helical flow of power law fluid was built in this paper. The relationship between average pressure gradient on pipe and some influence factors (pipe axial velocity, rotating angular velocity, drilling fluid circulation velocity, and axial coordination) was analyzed. Results showed that average pressure gradient caused by shear stress was only affected by average annular flow velocity, and it didn’t change along pipe length. Effect of rotating angular velocity on average pressure gradient on pipe was very small and could be negligible. A fitting function between average pressure gradient and average annular flow velocity was obtained in this end.

Scaling Formulae for the Wellbore Hydraulics Similitude with Drill Pipe Rotation and Eccentricity

2021 ◽  
Author(s):  
Thad Nosar ◽  
Pooya Khodaparast ◽  
Wei Zhang ◽  
Amin Mehrabian
Keyword(s):  
Power Law ◽  
Flow Rate ◽  
Annular Flow ◽  
Rotation Speed ◽  
Drilling Fluid ◽  
Drill Pipe ◽  
Flow Loop ◽  
Annular Flows ◽  
Fluid Rheology ◽  
Pipe Rotation

Abstract Equivalent circulation density of the fluid circulation system in drilling rigs is determined by the frictional pressure losses in the wellbore annulus. Flow loop experiments are commonly used to simulate the annular wellbore hydraulics in the laboratory. However, proper scaling of the experiment design parameters including the drill pipe rotation and eccentricity has been a weak link in the literature. Our study uses the similarity laws and dimensional analysis to obtain a complete set of scaling formulae that would relate the pressure loss gradients of annular flows at the laboratory and wellbore scales while considering the effects of inner pipe rotation and eccentricity. Dimensional analysis is conducted for commonly encountered types of drilling fluid rheology, namely, Newtonian, power-law, and yield power-law. Appropriate dimensionless groups of the involved variables are developed to characterize fluid flow in an eccentric annulus with a rotating inner pipe. Characteristic shear strain rate at the pipe walls is obtained from the characteristic velocity and length scale of the considered annular flow. The relation between lab-scale and wellbore scale variables are obtained by imposing the geometric, kinematic, and dynamic similarities between the laboratory flow loop and wellbore annular flows. The outcomes of the considered scaling scheme is expressed in terms of closed-form formulae that would determine the flow rate and inner pipe rotation speed of the laboratory experiments in terms of the wellbore flow rate and drill pipe rotation speed, as well as other parameters of the problem, in such a way that the resulting Fanning friction factors of the laboratory and wellbore-scale annular flows become identical. Findings suggest that the appropriate value for lab flow rate and pipe rotation speed are linearly related to those of the field condition for all fluid types. The length ratio, density ratio, consistency index ratio, and power index determine the proportionality constant. Attaining complete similarity between the similitude and wellbore-scale annular flow may require the fluid rheology of the lab experiments to be different from the drilling fluid. The expressions of lab flow rate and rotational speed for the yield power-law fluid are identical to those of the power-law fluid case, provided that the yield stress of the lab fluid is constrained to a proper value.

scholarly journals Peristaltic Transport of Power-Law Fluid in an Elastic Tapered Tube with Variable Cross-Section Induced by Dilating Peristaltic Wave

2021 ◽  
pp. 1293-1306
Author(s):  
Mohammed Ali Murad ◽  
Ahmed M. Abdulhadi
Keyword(s):  
Pressure Gradient ◽  
Cross Section ◽  
Power Law ◽  
Variable Cross Section ◽  
Peristaltic Transport ◽  
Peristaltic Wave ◽  
Variable Cross ◽  
Power Law Fluid ◽  
Opposite Behavior ◽  
Local Shear

The peristaltic transport of power-law fluid in an elastic tapered tube with variable cross-section induced by dilating peristaltic wave is studied. The exact solution of the expression for axial velocity, radial velocity, stream function, local shear stress, volume of flow rate and pressure gradient are obtained under the assumption of long wavelength and low Reynolds number. The effects of all parameters that appear in the problem are analyzed through graphs. The results showed that the flux is sinusoidal in nature and it is an increasing function with the increase of  whereas it is a decreasing function with the increase of . An opposite behavior for shear strain is noticed compared to pressure gradient.  Finally, trapping phenomenon is presented to explain the physical behavior of various parameters. It is noted that the size of the trapping bolus increases with increasing  whereas it decreases as  increases. MATHEMATICA software is used to plot all figures.

Analysis of Lubrication Theory for the Power Law Fluid

1993 ◽  
Vol 115 (1) ◽  
pp. 71-77 ◽  
Author(s):  
M. W. Johnson ◽  
S. Mangkoesoebroto
Keyword(s):  
Thin Film ◽  
Pressure Gradient ◽  
Power Law ◽  
Arbitrary Shape ◽  
Three Dimensional ◽  
Lubrication Theory ◽  
Slider Bearing ◽  
Power Law Fluid ◽  
Rigid Walls ◽  
Working Out

A lubrication theory for the power law fluid is developed and analyzed. Only the infinite width gap is considered. Considered is flow between rigid walls of arbitrary shape under combined Couette and squeezing motion with a pressure gradient. Equations appropriate to a thin film are derived by asymptotic integration of the three-dimensional equations of fluid mechanics. Further integration of these equations yields an algebraic equation for the pressure gradient. Working out the details of the structure of this equation enables us to develop a numerical algorithm for its solution. To illustrate the theory, it is used to calculate the pressure distribution for a parabolic slider bearing and the pressure gradient and velocity distribution when the mass flux is prescribed. The latter results are compared with results obtained earlier by Dien and Elrod (1983).

Sign in / Sign up

Export Citation Format

Share Document