微膨胀水泥浆在涠洲11-1N区块固井中的应用

Slightly swelling cement slurry used in Weizhou 11-1N Block cementing jobs.

涠洲11-1N区块油水层相距较近,隔层薄,固井时要完全封住水层、油层和油水层之间的隔层。采用以非渗透降失水剂为主、膨胀剂为辅组成的微膨胀水泥浆体系固井,该水泥浆气侵阻力大,能有效防止水泥石孔隙窜槽,同时能有效消除因水泥凝固后体积收缩造成的微环空间隙,增强水泥石的强度,提高水泥环与套管和井壁两个界面的胶结质量。现场应用表明,微膨胀水泥浆适用于井底静止温度低于120℃的固井作业,凝固后具有气侵阻力大和微膨胀特性,能有效封隔油气水层;清洗液+稠隔离液+清洗液+紊流清扫水泥浆组成的前置液能有效提高钻井液顶替效率,取得了固井质量SBT电测结果优良的效果。

In Weizhou 11-1N Block, as the distance from oil layer to water bed is short, cementing job is required to isolate them from each other totally. A slightly swelling cement slurry containing impermeable fluid loss reducer and swelling agent was employed. The gas-cutting resistance of this slurry is strong, which is good for preventing channeling from happening in setting slurry. The micro-annulus produced by cement stone shrinkage is avoided, the strength is increased and the cement bond quality is guaranteed. Application results showed the slightly swelling cement slurry is suitable for wells of lower than 120℃ down hole; it exhibits high resistance to gas-cut, and the slightly swelling property is especially good for oil/gas/water layers effectively. In addition, the pad fluid composed of cleaning fluid, thick spacer and turbulent slurry improved the drilling fluid displacement efficiency, and the cementing quality was excellent.