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.

摘要： 将钻井泥浆当作纯粘性幂律流体处理,较深人地研究了偏心环空中幂律流体层流螺旋流.提出了视粘度、速度、流量、压降及流动状态判别式的解析解;给出厂电算模拟示例通过室内验证及大庆油田11口井实际应用.表明了本文理论的精确性和实用性好.由本文的工作可知,在进行定向井水力参数设计时,造斜点以上环空压降可按同心环空螺旋流计算;造斜点以下可认为偏心度为100%.然后用本文理论汁算.

关键词: 偏心环空, 幂律流体, 螺旋流, 定向井, 水力参数设计