用于封固气层的泡沫水泥浆固井技术

Foamed cement slurry cementing technology used in plugging reservoir

鄂尔多斯盆地各气层压力相差较大,气层及气层上下含水,并有膏岩夹层,影响了水泥浆的顶替效率及水泥石的凝固和胶结。试验了多种水泥浆体系,还是出现了下部气层段声幅偏高的质量问题,据统计有40％的井气层或气层上下声幅值偏高。因此,决定采用化学发气泡沫水泥浆封固气层。该泡沫水泥浆体系由发气剂FCA、发气剂FCB、稳泡剂FCF以及缓凝剂FCR、水和油井水泥组成。现场应用表明,化学发气泡沫水泥浆具有浆体均匀稳定、流动性好、抗压强度发展迅速、稠化过渡时间短等特点,对侵入体系的气体具有乳化分散作用,使之形不成通道,有利于防窜。37口井用化学发气泡沫水泥浆封固气层,固井1次合格率达到100％;该防窜体系现场可操作性强,满足了鄂尔多斯气田探井、开发井的施工要求。

The displace effects of cement slurry and solidification and consolidation of cement stone are affected by formation characteristic of stratums pore pressure changes widely, water bearing in gas bed as well as in its upper and/or lower formation and gypsum intercalated bed in Erdos basin. 40 % of wells treated by conventional cement slurry in the basin have problems of higher sound acoustic amplitude in gas-zone as well as in its upper and/or lower bed. Thus, chemical gas release foamed cement slurry system has been used in plugging gas-zone in the basin to adapt the formation characteristics and to solve the problems. The system consists of gas generating agents FCA and FCB, foam stability agent FCF, retarder FCR, water and oil well cement. Field using indicates that the cement slurry system has such properties as symmetrical pulp body, good flow ability, high compressive, short thic-king transition time, significant roles in emulsifying and dispersing inbreaking gas and preventing gas channel. The cement slurry system has been used in 37 wells in Erdos to plug gas-zone and cementing success rate of 100% has been reached. This system is easy to use in field and can satisfy the work requirements of exploratory wells in the basin.