摘要
为了提高水泥环的层间封隔能力,利用ESEM、Zeta电位仪、FTIR及钻井液滤饼模拟等方法,研究了钻井液及其滤饼对固井第二界面质量的影响,并提出了一种滤饼清除技术。研究结果表明:钻井过程的钻井液性能不满足提高固井第二界面胶结质量的要求,该钻井液容易在井壁上形成虚厚的滤饼,将严重恶化水泥石与地层间的界面胶结,降低固井第二界面质量,室内模拟水泥石与岩心间界面的7 d胶结强度仅为0.12 MPa。在固井前调整钻井液的p H值≈11、流性指数n>0.75、动切力YP≈5 Pa,通过提高钻井液的pH值和流变性以破坏钻井液中聚合物的化学结构、增加钻井液中高分子处理剂的亲水性,并提高钻井液中黏土颗粒表面的ζ电位、增加黏土颗粒间的分散作用,可提高对滤饼的清除程度及水泥浆的顶替效率,水泥石与岩心界面间7 d的胶结强度由0.12 MPa提高到了1.18 MPa。同时,固井前调整钻井液性能并结合配套浆柱结构技术,已在大港油田连续应用14井次,固井第二界面优质率从23.1%提高至71.6%。
In order to improve the zone islation quality of cement-sheath,the ESEM,Zeta potential analyzer,FTIR measurements and the method of filter-cake simulation were applied to study the influence of drilling fluid and its filter-cake on the second interface cementation in primary cementing,and a cleaning technique of low strength filter-cake（LSFC）was proposed. The results showed that the properties of drilling fluid,used during drilling operation,was not satisfied to improve quality of second interface,the drilling fluid was easy to form LSFC on the wellbore,which will decrease the shear strength of second interface between cement sheath and formation,and the shear strength between cement stone and core was only 0.12 MPa after curing for 7 days. A cleaning technique of LSFC was presented to improve the shear strength,including the improvement of the p H value of drilling fluid to damage chemical structure and to increase the hydrophily of drilling fluid additives,and the ζ potential of particles in drilling fluid increased to increase the dispersion between particles.When Controlling the properties of drilling fluids to make the pH≈11,the flow behaviour index n〉0.75 and yield point YP≈5 Pa,the shear strength between cement stone and core could be increased from 0.12 MPa to 1.18 MPa. The technique combining with the suitable slurry column structure,had been successfully applied on 14 wells in Dagang oilfield. The cementing quality of second interface between cement sheath and formation was substantially improved,the average high-quality increased from 23.1% to 71.6%.
作者
刘开强
赵殊勋
李炜
王海滨
易旦
王金山
郭小阳
LIU Kaiqiang;ZHAO Shuxun;LI Wei;WANG Hai-in;YI Dan;WANG Jinshan;GUO Xiaoyang(Key Laboratory Oil and Gas Reservoir Geology and Exploration, Southwest Petroleum University, Chengdu, Sichuan 610500, P R of China;CNPC Bohai Drilling Engineering Company Limited, Tianjin 300452, P R of China;CNPC Tarim Oilfield Company, Korla,Xinjiang 841000, P R of China;CNPC Dagang Oilfield Company, Tianfin 300452 ,P R of China)
出处
《油田化学》
CAS
CSCD
北大核心
2018年第1期16-21,共6页
Oilfield Chemistry
关键词
调整钻井液
虚滤饼
流变性
絮凝结构
胶结强度
drilling fluid
low strength filter-cake
rheological property
flocculation structure
shear strength
