摘要
控压钻井是针对"窄安全压力窗口"现象所引起的勘探开发过程中的钻井难题所提出的,井筒压力分布的准确预测是保证控压钻井顺利实施的前提,为提高井筒压力的预测精度需准确计算环空摩阻压耗,应用量纲分析理论,综合考虑钻具接头、钻具旋转的影响,修正了环空摩阻压耗计算模型,提高了井筒压力的预测精度.模型研究表明:随着钻井液排量的增加,钻井液从层流变为紊流,局部摩阻压耗明显增加;且井越深,接头的累计压耗越大,接头对总摩阻压耗的贡献增加.随着钻具旋转速度的增加,环空压耗的增加或减少取决于惯性力与剪切稀释的共同作用.
Managed pressure drilling is proposed to solve drilling problems which induced by narrow safety pressure window. Wellbore pressure or ECD must be predicted accurately and maintained within the narrow margin to avoid kicks and circulation losses, which is the key for safe and successful drilling. To improve the prediction accuracy of wellbore pressure,friction pressure loss must be calculated accurately. In this article, the effects of tool joint,drillpipe rotation and eccentric annulus on frictional pressure loss were investigated based on dimensional analysis theory. As a result, annulus friction pressure loss model was improved,which enhanced wellbore pressure prediction accuracy. Model studies show that as the flow rates increases, flow regime change from laminar flow to turbulent flow, strong hydraulic resistance created by the tool-joint that increases the local annular pressure loss significantly.And as well depth increases, cumulative pressure loss of tool joint will be greater, and the contribution of tool joint to total pressure loss increases. As pipe rotation increases, pressure loss may increase or decrease depending on the overall result of inertial effect and shear thinning.
作者
孙士慧
李改海
逯广东
于晓文
于国庆
SUN Shi-hui LI Gai-hai LU Guang-dong YU Xiao-wen YU Guo-qing(Petroleum Engineering College, Northeast Petroleum, Daqing 163318, China Daqing Oil Filed Co., Ltd. of PetroChina, Daqing 163453, China)
出处
《数学的实践与认识》
北大核心
2017年第19期76-83,共8页
Mathematics in Practice and Theory
基金
国家科技重大专项课题"钻井工程一体化软件"(2016ZX05020-006)
关键词
钻具接头
钻具旋转
环空偏心
摩阻压耗
量纲分析
tool joint
drillpipe rotation
eccentric annulus annular pressure loss
dimensionalanalysis
