防气窜泡沫水泥浆的研究与应用

长庆气田属低压低渗透气田．气层多．含气井段长，压力梯度不等，固井时易发生气侵窜槽．造成水泥石界面胶结不良。针对长庆气田的特点，研究出了防气窜泡沫水泥浆，外加剂由氮气发气剂GFQ-1和GFQ-2、稳泡剂GWP和缓凝剂GH-2组成，GFQ-1和GFQ-2与GWP之问的最佳比例为4g：5mL；8mL。现场试验表明，GFQ-1与GFQ-2的反应平稳，气体量易控制；泡沫封闭稳定，渗透率低，泡沫细小、均匀．不易破裂．在浆体中均匀分布；浆体稳定性和流动性好．游离液为零；水泥石抗压强度高。水泥浆密度低；水泥浆具有可膨胀性和可压缩性．直角稠化，水泥石胶结强度高，可有效防止油气水窜．防气窜泡沫水泥浆配方简单．施工方便，成本低。气层井段优质率为87％，合格率为100％。

Study on anti-channeling foam cement slurry and its application

Low pressure and permeability, imparity pressure gradient and long gas section reservoirs exist in Changqing oilfield, and gas channeling often occurred during cementing which leads to poor interface cementation. Based on the formation characteristics of the field, an anti-channeling foam cement slurry has been developed. Additives are Nitrogen gas forming agent GFQ-1 and GFQ-2, foam stabilizer GWP and retarder GH-2. The best proportion of GFQ-1: GFQ-2; GWP is 4g:5 mL: 8 mL. Applications in fields showed the following results: GFQ-1 reacted stably with GFQ-2 and the volume of gas could be easily controlled; the foams with the properties of good isolation, low permeability, fine and the same size and hardly breakup distributed uniformly in the slurry body; the slurry body was stable, flowable with no free liquid; compressive strength of cement stone was high and its density was low; cement slurry has properties of expansibility, compressibility and right angle thickenings oil, gas and water channeling could be prevented because of high cementing strength of the cement stone; the cement slurry was simple and easy for field using with low treating cost. The cementing qualification rate in gas section was 100 % and excellent rate was 87%.