高温抗盐直角稠化水泥浆体系

Study and application of a high temperature and salt-resisting cement slurry system.

针对深井油气层埋藏深、分散,井温高、封固段长等复杂情况,优选出了一种高温抗盐直角稠化水泥浆体系。该体系外加剂由高温降失水剂G301(或G306)、高温缓凝剂GH-Ⅱ(GH-ⅡB)和高温减阻剂USZ组成。该水泥浆体系能够抗盐达饱和盐水,失水量小于150mL,抗温达160℃,低温养护后强度大于14MPa,高温养护后强度仍大干15MPa,表现出了很好的抗高温强度衰退性能;稠化时间可调,过渡时间短;易于配浆,流动性好,能够适应深井固井需要。在不同油田的高温固井实践表明,使用该水泥浆固井施工顺利,固井质量优质。

A high temperature and salt-resisting cement slurry system was studied to cement long completion intervals based on characteristics of deep wells such as high temperature and productive layers distributing deeply and dispersedly. This system is composed of high temperature filtrate reducer G301 (or G306), high temperature retarder GH-Ⅱ (GH-HB) and high temperature drag reducer USZ. Evaluation tests showed that, the high temperature and salt-resisting cement slurry has excellent salt durability up to saturated salt solution; it works well at temperature lower than 160℃; the set slurry has compressive strength more than 14 MPa after aging at low temperature, and the value is more than 15 MPa even after aging at high temperature. All these data illustrating that the system possesses excellent strength retrieve resistance at high temperature. The rheological property is good, the fluid loss is less than 150 mL, the thickening time is adjustable with short transient time. In addition, this slurry is easy to prepare onsite. Several cementing jobs with the cement slufry in different oilfields were successful with high cementing quality.