摘要
为提高固井水泥环的抗CO_2腐蚀能力,开发了富硅铝质活性外掺料(HA)。通过比较不同碳化龄期水泥石的抗压强度、分析孔结构、测定渗透率、分析碳化层的成分和显微形貌等方法,对水泥石的抗碳化性能进行了研究。结果表明,加HA水泥石抗CO_2腐蚀能力明显优于净浆水泥石和掺硅灰水泥石:加HA水泥石在CO_2压力2 MPa、95℃腐蚀介质中养护28和90 d后,试样的抗压强度为35.4和33.7 MPa,较同龄期盐水养护试样分别降低了3.01%和13.14%(净浆水泥石分别降低了7.75%和31.15%),试样总孔隙率分别为19.87%和21.45%(净浆水泥石分别为28.81%和31.85%),且有害孔(直径>100 nm)所占比例小;在7 MPa驱替压力下,两个腐蚀龄期的加HA水泥石均未发生渗滤(净浆水泥石的渗透率分别为1.21×10^(-3)μm^2和1.68×10^(-3)μm^2);碳化90 d后的加HA水泥石外层试样中CaCO_3的衍射峰强度明显低于净浆水泥石,且碳化试样的产物呈连续致密,与净浆水泥石腐蚀后形成颗粒的结构明显不同。
Rich silicon-aluminum active admixture （HA） has been developed with the aim at improving the performance of anti-carbonation of oil well cement sheath. The compressive strength of set cement,its pore struc ture,permeability,component and micro-morphology of carbonated specimens at different ages were analyzed. The performance of anti-carbonization was investigated. The results showed that the anti-carbonation property of set ce- ment with HA agent was higher than that of the pure cement and those containing silica fume. Under CO2 pressure of 2 MPa and temperature of 95 ℃ ,the compressive strength of set cement with HA agent was 35.4 MPa and 33. 7 MPa respectively with aging for 28 and 90 days,which decreased by 3.01% and 13. 14% respectively compared with those samples after salt water curing （the compressive strength of pure cement was reduced by 7.75% and 31.15% respectively）. The total porosity was 19. 87% and 21.45% （the porosity of pure set cement was 28.81% and 31. 85%）,and the volume ratio of harmful pores （with diameter 〉100 μm） was small. These two corroded set cement with HA agent percolation did not occur at the driving pressure of 7 MPa （the pure set cement had permea bility of 1.21×10^-3μm^2 and 1.68×10^-3μm^2）. The X-ray diffraction intensity of CaCO3 in set cement with HA agent was lower than that of pure set cement after carbonization for 90 days, the carbonized samples are compact continuously, different from the particle structure of pure set cement evidently.
出处
《石油钻探技术》
CAS
北大核心
2011年第4期40-43,共4页
Petroleum Drilling Techniques
基金
国家高技术研究发展计划("863"计划)项目"低渗透油气藏复杂井用非水泥基固井材料研究"(编号:2006AA06Z225)
江苏省企业博士基金项目"海洋深水油气田固井用多功能材料研究"(编号:BK2009666)资助
关键词
固井
水泥浆
水泥石
二氧化碳腐蚀
水泥添加剂
抗压强度
well cementing
cement slurry
set cement
carbon dioxide corrosion
cement additives
corn pressive strength
