摘要
为实现基于井下分离的深水双梯度钻井早期气侵监测,基于井筒气液两相流理论,建立考虑密度突变的气液两相流模型。通过实例对比气侵发生后深水双梯度钻井和常规单梯度钻井环空出口液相表观速度和出口流量变化规律的差异性,分析不同井深、气侵量、分离器位置、重/轻质钻井液密度差、排量及井口回压条件下的环空出口流量变化。结果表明气侵发生后,当气体前沿到达分离器位置时,深水双梯度钻井环空出口液相表观速度和流量变化率均发生二次突增;井深越深、气侵量越小、分离器与钻头间距越小、重/轻质钻井液密度差越小、排量越大,均会导致突增后的环空出口流量变化率减小;通过监测环空出口流量的早期气侵监测新方法在气体前沿到达分离器位置时即可进行气侵识别,有利于更早地发现气侵并及时采取控制措施,保证深水钻井安全。
In order to realize early gas kick monitoring in deepwater dual-gradient drilling based on downhole separation,a gas-liquid two-phase flow model considering sudden density change was established for the flow in wellbore.The differences of the apparent liquid velocity and the flow rate at outlet between the deepwater dual-gradient drilling and the conventional single gradient drilling after gas kick were compared in a case study.The variation of the annular outlet flow rate was analyzed under different influencing factors,such as well depth,gas rate,separator position,density difference between heavy and light drilling fluids,displacement and wellhead backpressure.The results show that,for deepwater dual-gradient drilling and after a gas kick,the apparent liquid velocity and the flow rate at annular outlet increase twice when the gas front reaches the separator position.The deeper the well depth,the smaller of the gas rate,the distance between separator and bit and the density difference between heavy and light drilling fluids,and the larger the displacement,all of these can lead to the decrease of the annular outlet flow rate after the sudden increase.This new method of early gas kick detection by monitoring annular outlet flow can be used to identify gas kick when the gas front reaches to the separator,which is conducive to early detection of gas kick and its timely control to ensure the safety of deepwater drilling.
作者
王江帅
李军
柳贡慧
罗鸣
任美鹏
WANG Jiangshuai;LI Jun;LIU Gonghui;LUO Ming;REN Meipeng(College of Petroleum Engineering in China University of Petroleum(Beijing), Beijing 102249, China;College of Petroleum in China University of Petroleum(Beijing) at Karamay, Karamay 834000, China;Beijing University of Technology, Beijing 100192, China;CNOOC China Limited, Zhanjiang Branch, Zhanjiang 524000, China;CNOOC Research Institute Company Limited, Beijing 100028, China)
出处
《中国石油大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2020年第6期73-78,共6页
Journal of China University of Petroleum(Edition of Natural Science)
基金
国家自然科学基金重点项目(51734010)。
关键词
深水双梯度钻井
气液两相流
密度突变
分离器位置
早期气侵监测
deepwater dual-gradient drilling
gas-liquid two-phase flow
sudden density change
separator position
early gas kick detection
作者简介
第一作者:王江帅(1993-),男,博士研究生,研究方向为深水双梯度钻井、控压钻井、井筒多相流与井控,E-mail:wjs125126@163.com;通信作者:李军(1971-),男,教授,博士,博士生导师,研究方向为钻完井新技术,E-mail:lijun446@vip.163.com。
