渤海浅层气防窜水泥浆体系的研究与应用

环空带压是渤海湾浅层气固井存在的一大技术难题,为此根据渤海湾浅层气特征,分析固井技术难点,设计了2种固井方案。方案A引入膨胀材料或增塑材料,方案B引入自修复材料。实验结果显示,当同时引入膨胀剂与纤维后,96 h胶结强度仅提高15%左右,因此可知水泥浆的防窜能力不会有明显改善。而引入自修复材料后,水泥石的裂缝封堵率达到95%以上。分析认为,方案B的自修复封堵性能和工程性能均满足设计要求,该水泥浆体系经现场应用,取得良好的施工效果。

Study and Application of Anti-channeling Cement Slurry Used in Shallow Gas Zones in Bohai

Two optimized cement slurries are designed to deal with sustained casing pressure problem in cementing shallow gas zones in Bohai, with the first one prepared with expanding material and plasticization agent, the second one with self-healing material. When expanding material and fibers are added into a cement slurry, the 96-hour cement strength of the slurry is increased only by 15%, which means that the anti-channeling capacity of the cement slurry will not be improved notably. When seal-healing material is added into the cement slurry, the sealing efficiency of the set cement reaches 95%, or even higher. It is thus believed that cement slurries treated with self-healing material satisfy the need for well cementing, and this is also proved by field practices.