摘要
深水浅表层固井作业过程中由于海底低温导致水泥环早期力学强度发展缓慢、内部密实度不高,易引发水气窜流,进而导致固井质量低劣甚至密封失效等复杂情况。为此,采用分形特征方程对G级油井水泥、纳米CaCO_(3)(NC)和漂珠(CS)进行紧密堆积,然后结合室内实验评价,优选出了一套密度为1.50 g/cm^(3)的具有低温早强性能的三元固相水泥浆体系,并利用抗压强度测试、XCT、SEM等方法对紧密堆积体系的增强机理进行了表征和分析。研究结果表明:(1)三元紧密堆积体系早期力学强度发展快速,在10℃的低温条件下,24 h抗压强度可达3.5 MPa以上;(2)相比于相同密度的NC二元体系和CS二元体系,孔隙率降低了19.10%~33.05%,抗压强度提高了7.0%~21.1%;(3) NC可以为水泥水化提供成核位点、填充细化孔隙,CS可以部分替代水而提高体系致密性,在两种材料的协同作用和紧密堆积效应下可实现早期力学强度的快速发展。结论认为,三元固相级配水泥浆体系利用紧密堆积理论发挥了3种材料的各自优势,进而实现了早期力学强度的快速发展,对于深水井表层套管固井作业防止水气窜流具有很好的理论指导意义和应用推广价值。
In the process of cementing in deepwater shallow formations,the low temperature at the sea floor results in slow development of the early mechanical strength of the cement sheath and low internal compactness of the cement sheath,which leads to water and gas channeling,causing poor cementing quality and even seal failure and other complex accidents.In this paper,the fractal characteristics equation is used for the close packing of G-grade oil-well cement,nano CaCO_(3)(NC) and cenospheres(CS).Then,a set of ternary solidphase cement slurry system with a density of 1.50 g/cm^(3) and the properties of low temperature and early strength is selected through indoor experimental evaluation.Finally,the strengthening mechanisms of close packing system are characterized and analyzed by means of compressive strength test,XCT and SEM.And the following research results are obtained.First,the mechanical strength of the ternary close packing system develops rapidly in the early stage,and the compressive strength at 24 h can reach more than 3.5 MPa under 10℃.Second,compared with the NC binary system and the CS binary system with the same density,the ternary system is 19.10%-33.05%lower in porosity and 7.0%-21.1% higher in compressive strength.Third,NC can provide nucleation sites for cement hydration and fill and refine the pores,and CS can partially replace the water to improve the densification of the system.Under the synergistic effect of these two materials and the close packing effect,the early mechanical strength can develop rapidly.In conclusion,the ternary solid-phase cement slurry system gives full play to the advantages of three kinds of materials on the basis of close pacing theory,so as to realize the rapid development of early mechanical strength,which has certain theoretical significance and application value for preventing water and gas channeling during the cementing operation of surface casing in deepwater wells.
作者
郑少军
谷怀蒙
刘天乐
陈宇
蒋国盛
王韧
代天
秦榜伟
徐浩
万涛
ZHENG Shaojun;GU Huaimeng;LIU Tianle;CHEN Yu;JIANG Guosheng;WANG Ren;DAI Tian;QIN Bangwei;XU Hao;WAN Tao(Faculty of Engineering,China University of Geosciences,Wuhan,Hubei 430074,China;Engineering Research Center of Rock-Soil Drilling&Excavation and Protection,Ministry of Education,Wuhan,Hubei 430074,China;CNOOC Research Institute Co.,Ltd.,Beijing 100028,China;CNPC Engineering Technology R&D Co.,Ltd.,Beijing 102206,China;No.1 Mud Logging Company,CNPC Bohai Drilling Engineering Co.,Ltd.,Tianjin 300280,China)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2024年第2期122-131,共10页
Natural Gas Industry
基金
国家自然科学基金项目“水合物分解对深水固井水泥环孔隙特征与力学性质的影响机制研究”(编号:42072343)
国家高层次人才特殊支持计划(编号:107-KZ23Z20016)
中央高校基本科研业务费专项资金(中国地质大学)优秀青年团队项目“深水天然气水合物地层安全高效固井关键技术”(编号:107-G1323523046)。
关键词
深水
低温
低密度固井水泥浆
分形理论
抗压强度
Deepwater
Low temperature
Low-density cement slurry
Fractal theory
Compressive strength
作者简介
郑少军,1993年生,助理研究员,博士,主要从事非常规地层固井理论与技术方面的研究工作。地址:(430074)湖北省武汉市洪山区鲁磨路388号。ORCID:0000-0002-2148-9090。E-mail:sjzheng212@cug.edu.cn;通信作者:刘天乐,1984年生,教授,博士,主要从事非常规固井与特种加固技术、深水油气资源勘探与开发等方面的研究工作。地址:(430074)湖北省武汉市洪山区鲁磨路388号。E-mail:liutianle@cug.edu.cn。
