摘要
四川盆地川东地区高峰场构造已钻井资料表明,钻井过程中钻井液受污染、石膏层蠕变后造成井下复杂、卡钻事故的现象频繁发生,加之该区域志留系小河坝组及以下地层完成井较少,无有效参考资料,地质复杂,可预见性较差,FT1井为该区域的第一口非标大井眼探井,故面临井壁失稳、长井段泥岩造浆及膏盐污染、环空返速低、钻井液量大等特殊情况,造成维护困难,以及石炭系采空区与下伏异常高压地层引起的防漏、防喷、防高压差卡钻等难题更加突出。为满足井下安全快速钻进要求和尽快完成超深层油气藏地质勘探开发,通过室内相关评价实验对钻井液配方和维护工艺进行分析,结合现场维护应用情况,完成了主要非标大井眼段钻井液体系和维护工艺的优化技术。结果表明:维护工艺和体系优化后的钻井液性能在护壁防塌、携砂性、抑制性、抗温、抗污染、封堵、润滑等多项性能方面较传统钻井液体系有更大的优势,有效解决了抗膏盐污染、井壁失稳、防漏、防卡等问题,现场应用效果好,提速显著,杜绝了钻进过程中复杂事故的发生。
Drilling data on Gaofengchang structure in eastern Sichuan Basin indicates some phenomena frequently in drilling,such as contaminated drilling fluid as well as downhole complexities and sticking after gypsums creepage.In addition,there is no available reference data due to only few wells completed in Xiaoheba Formation and its below,and complex geological conditions with poor predictability.Being the first exploration one with non-standard large borehole in this area,FT1 well was also confronted with well-bore instability,large section of mud-making and gypsum-salt pollution,low annular velocity and heavy drilling-fluid volume,making its maintenance difficult and more prominent challenges in preventing leakage,blowout,and high-pressure differential sticking from the Carboniferous goaf and its below with abnormal high pressure.Thus,both drilling-fluid formula and maintenance process were analyzed through some indoor experiments in order for safe and fast drilling together with exploration and development of ultra-deep reservoirs as soon as possible.Moreover,combined with on-site maintenance,the optimized drilling fluid and its maintenance process were established for non-standard large-borehole section.Results show that this optimization is superior to traditional drilling fluid in such performances as collapse prevention,sand-carrying capacity,inhibition,temperature resistance,pollution resistance,sealing and lubrication.As a result,many problems can be solved with effect,including gypsum-salt pollution,wellbore instability,lost circula-tion,and sticking.ROP is improved evidently after its application,and complexities no longer occur.
作者
江显俊
肖金裕
兰太华
傅相友
贾兴明
JIANG Xianjun;XIAO Jinyu;LAN Taihua;FU Xiangyou;JIA Xingming(Drilling Fluid Technology Service Company,CNPC Chuanqing Drilling Engineering Company Limited,Chengdu,Sichuan 610056,China)
出处
《天然气勘探与开发》
2024年第1期63-72,共10页
Natural Gas Exploration and Development
关键词
非标大井眼
环空返速低
膏盐污染
抗温钻井液
井壁失稳
钻进提速
Non-standard large borehole
Low annular velocity
Gypsum-salt pollution
High-temperature resistant drilling fluid
Wellbore instability
ROP improvement
