摘要
针对深水井B、C环空流体固相沉积下环空泄压通道堵塞风险,开展常见深水钻井液体系固相沉积测试,获得不同钻井液体系固相沉降高度及沉降后固相渗流特性,并基于固相渗流特性参数,考虑环空流体固相沉积影响,建立渗流作用下环空带压预测分析方法,并开展实例分析。结果表明:沉降高度油基钻井液>EZFLOW钻井液>HEM钻井液,沉降后固相渗透率EZFLOW钻井液>HEM钻井液>油基钻井液,渗透率最高达到2.216μm^(2),在环空流体固相沉积条件下,随环空流体黏度降低及地层渗透率、裸眼段长度增加,流体流动黏性力降低,且与地层接触渗流面积增大,环空流体渗流量增大,降低钻井液流体黏度、提高水泥环裸眼段长度可以提高深水井B、C环空压力释放能力,但由于固相沉积影响,其渗流流量远小于无固相沉积条件下环空压力降低速度,且固相沉降后存在无法泄压的风险。
To mitigate the risk of annular pressure buildup caused by solid-phase deposition in the B and C annuli of deep-water wells,experimental tests were conducted on sedimentation behavior using common deep-water drilling fluid systems.The sedimentation height and post-settling solid-phase permeability of various drilling fluids were measured.Based on the parameters of solid phase percolation characteristics,and considering the impact of annular fluid solid deposition,a predictive analytical method was established for annular pressure under percolation conditions.Case analysis was conducted to validate the approach.Results show that the sedimentation height follows the order:oil-based drilling fluid>EZFLOW drilling fluid>HEM drilling fluid.In contrast,the postsettling solid-phase permeability is ranked as EZFLOW drilling fluid>HEM drilling fluid>oil-based drilling fluid,with a maximum permeability of 2.216μm^(2).Under annular fluid solid-phase deposition conditions,reductions in annular fluid viscosity,increases in formation permeability,and longer open-hole cement sheath sections reduce fluid viscous resistance,enlarge the seepage contact area with the formation,and enhance fluid flow.Therefore,reducing drilling fluid viscosity and extending the open-hole cement sheath length can improve the pressure release capacity in the B and C annuli of deep-water wells.However,the presence of solid-phase deposition significantly restricts seepage flow rates compared to conditions without deposition,leading to a potential risk of incomplete pressure relief following solid-phase sedimentation.
作者
吴怡
张兴全
张天玮
张智
丁剑
WU Yi;ZHANG Xing-quan;ZHANG Tian-wei;ZHANG Zhi;DING Jian(CNOOC(China)Co.,Ltd.Beijing Research Center,Beijing 100000,China;National Key Laboratory of Offshore Oil and Gas Exploitation,Beijing 100000,China;State Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering,Southwest Petroleum University,Chengdu 610500,China;School of Mechanical Engineering,Southwest Petroleum University,Chengdu 610500,Chin)
出处
《科学技术与工程》
北大核心
2025年第20期8483-8489,共7页
Science Technology and Engineering
基金
国家自然科学基金(U22A20164,52074234)。
关键词
深水井
环空带压
环空流体
固相沉积
渗流
deep wells
annular pressure
annulus fluid
solid phase deposition
seepage
