天然气工业2024，Vol.44Issue(2)：122-131,10.DOI:10.3787/j.issn.1000-0976.2024.02.012
基于紧密堆积理论的深水低密度三元固相水泥浆体系
Deepwater low-density ternary solid phase cement slurry system based on close packing theory
摘要
Abstract
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 CaCO3(NC)and cenospheres(CS).Then,a set of ternary solid-phase cement slurry system with a density of 1.50 g/cm3 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.关键词
深水/低温/低密度固井水泥浆/分形理论/抗压强度Key words
Deepwater/Low temperature/Low-density cement slurry/Fractal theory/Compressive strength引用本文复制引用
郑少军,万涛,谷怀蒙,刘天乐,陈宇,蒋国盛,王韧,代天,秦榜伟,徐浩..基于紧密堆积理论的深水低密度三元固相水泥浆体系[J].天然气工业,2024,44(2):122-131,10.基金项目
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). （编号:42072343）
