关键词: 偏心环空, 幂律流体, 螺旋流, 定向井, 水力参数设计

Abstract: Thinking of drilling fluid as power-law fluid in this paper,the authors study the law of laminar helical flow of power-law fluid in eccentric annuli.The analytical solutions of apparent viscosity,velocities,flow rate,pressure drop and the stability parameter are presented.Results of numeral simulations are given.Studies of laboratory test and actual applications of eleven wells of Daqing oil field verified that the precision and actual application of the theory in this paper are good.On the other hand,from this paper we know that the flow of annulus above the kick off point can be considered as helical flow of coeentric annulusand under the kick off point can be considered as helical flow of eccentric annulus of 100% eccentricity.for designing hydraulic parumeters of directionril wells by the theory of this paper.