摘要
针对页岩地层水基钻井液井壁稳定性问题,从页岩储层矿物理化特性分析入手,探究基于长效抑制和优级封堵的页岩气水基钻井液评价方法,并形成体系且成功进行现场应用。实验结果表明:水平段龙马溪红页岩中膨胀性黏土矿物质量分数为32%,以伊利石为主,属于硬脆性页岩;通过膨润土造浆率实验优选出页岩抑制剂PHLY,通过粒径分析实验以及滤失实验优选出封堵剂NAT,其具有0.5~7.6μm的续粒径分布,与地层孔隙有良好的匹配性。结合优化实验,形成了一套适用于页岩气水平井水基钻井液体系,该体系API滤失量在2.9~3.3 mL之间,HTHP滤失量在9.4~10.2 mL之间,封堵效率高,具有良好的流变性,动塑比在0.36~0.48之间;极压润滑系数为0.065,可大幅度降低钻井过程中的摩阻扭矩。现场试验表明,该钻井液体系具有良好的抑制和封堵能力,施工过程中无明显掉块,井眼规则且起下钻顺利,体系综合性能优异,满足现场需求。
Aiming at the problem of wellbore stability of water-based drilling fluid in shale formation,starting from the analysis of physical and chemical characteristics of shale reservoirs,the evaluation method of shale gas water-based drilling fluids based on long-term inhibition and superior plugging was explored,and a system was formed.And field application was successfully carried out.The experimental results showed that the mass fraction of expansive clay minerals in Longmaxi red shale in the horizontal section was 32%,mainly composed of illite,which belonged to hard and brittle shale;the shale inhibitor PHLY was selected through the experiment of bentonite slurry rate,and the shale inhibitor PHLY was selected through the particle size analysis.The plugging agent NAT was selected from the diameter analysis experiment and fluid loss experiment,which had a continuous particle size distribution within 0.5~7.6μm and had a good match with the formation pores.Combined with optimization experiments,a set of water-based drilling fluid system suitable for shale gas horizontal wells was formed.The API fluid loss of this system was between 2.9 mL and 3.3 mL,and the HTHP fluid loss was between 9.4 mL and 10.2 mL.had high plugging efficiency and good rheology,the dynamic plastic ratio was within 0.36~0.48;the extreme pressure lubrication coefficient was 0.065,which could greatly reduce the frictional torque during drilling.The field test showed that the drlling and fluid system had good suppression and plugging ability,no obvious block falling during the construction process,the wellbore was regular and the tripping was smooth,and the comprehensive performance of the system was excellent,which met the needs of the site.
作者
王智鑫
WANG Zhi-xin(Daqing Oil Field Oil Production Engineering Research Institute,Daqing Heilongjiang 163000,China)
出处
《当代化工》
CAS
2023年第9期2153-2157,共5页
Contemporary Chemical Industry
基金
中国石油天然气集团公司工程技术科技统筹项目,长宁页岩气优快钻完井技术研究(项目编号:2021T-003-001)。
关键词
页岩
水平井
水基钻井液
性能评价
Shale
Horizontal well
Water-based drilling fluid
Performance evaluation
