摘要
该文基于水平井段岩屑运移实验,引入三参数的赫巴流体流变模式,使得计算结果与实际更为接近;通过数值模拟得到了钻井液黏度、密度、流速、钻杆旋转和偏心对岩屑速度分布的影响规律。计算结果表明:增大钻井液密度有利于岩屑运移,为了更好地提高岩屑速度,钻井液密度应高于1300 kg/m3;随着钻井液黏度的增大,环空窄间隙岩屑颗粒的运移速度也随之增加,特别是当黏度高于30 m Pa·s时,增加效果明显;岩屑颗粒运移,存在一个临界流速,在该算例条件下,当泵排量高于14 L/s时,岩屑速度增加明显;由于钻杆的旋转作用使得环空流体产生了切向速度,钻杆不旋转岩屑最高速度为0.395 m/s,建议钻杆转速应高于80 r/min;偏心度为0.2的情况下,窄间隙环空最大速度从1.145 m/s下降到0.831 m/s,当偏心度增加到0.8时,岩屑速度只有0.437 m/s,为了能够充分提高携岩运移速度,偏心度尽量控制在0.5以内。文中还回归了适合于大位移水平井的岩屑床厚度计算公式,得到了岩屑床运移速度分布规律。
Based on horizontal well cuttings migration experiment, a three parameter H-B fluid rheological model is introduced, which verifies the calculation results more close to the actual. Through the numerical simulation, the influence law of drilling fluid velocity, density, flow rate and the rotation, eccentricity of drill pipe on cuttings transport is obtained. The calculationresults show that increasing drilling fluid density is beneficial to cuttings migration. In order to improve the speed of cutting migration, the drilling fluid density should be higher than 1300 kg/m3. As the drilling fluid viscosity increases, migration velocity of narrow clearance also increases, especially when the viscosity is higher than 30 mPa-s. As to the migration velocity, there is a critical velocity. Under the conditions of this calculation example, when the pump displacement is higher than 14 L/s, the cuttings speed increases significantly. When annulus fluid produces tangential velocity because of the drill pipe rotation, the maximum speed of cuttings migration can be 0.395 m/s, thus recommended drill speed should be higher than 80 r/min. If the eccentricity is 0.2, the maximum velocity of narrow clearance is decreased from 1.145 m/s to 0.831 m/s. when the eccentricity increases to 0.8, cutting speed is only 0.437 rn/s. In order to improve the cuttings transport speed fully, eccentricity should be controlled within 0.5. A suitable for extended horizontal well formula of cutting-bed thickness is regressed, and also the cutting-bed migration velocity distribution is obtained.
出处
《水动力学研究与进展（A辑）》
CSCD
北大核心
2014年第6期739-748,共10页
Chinese Journal of Hydrodynamics
基金
国家自然基金(51104172
U1262202)
国家高技术研究发展计划项目("863"计划
2012AA091501)~~
关键词
水平井钻井
岩屑运移
速度分布
数值模拟
horizontal well drilling, cuttings transport, velocity distribution, numerical simulation
