发明授权
- 专利标题: Set retarders for foamed cements
- 专利标题(中): 设置发泡水泥的缓凝剂
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申请号: US09569422申请日: 2000-05-12
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公开(公告)号: US06372037B1公开(公告)日: 2002-04-16
- 发明人: Stuart E. Lebo, Jr. , Shane L. Resch
- 申请人: Stuart E. Lebo, Jr. , Shane L. Resch
- 主分类号: C04B2418
- IPC分类号: C04B2418
摘要:
An improved non-dispersing set retarder additive for foamed cements, cement compositions containing the additive, and methods of cementing in a subterranean zone penetrated by a well bore are provided. The set retarder additive includes a blend of a sulfonated lignin, preferably a lignosulfonate, with an alkali lignin, preferably a kraft lignin, having an organic sulfur content of 0-3.5% by weight in a ratio of about 6:4 to 8:2. The methods are basically comprised of the steps of preparing a foamed cement composition comprised of hydraulic cement, a non-dispersing set retarder, sufficient water to form a slurry, sufficient gas to foam the slurry and a foaming and foam stabilizing surfactant present in an amount sufficient to facilitate the formation of the foam and stabilize the foamed cement composition.
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