水泥浆胶凝失重与套管轴向拉力关系实验研究

水泥浆固化过程是固井工程的重要环节。水泥浆固化好坏直接影响固井质量,继而影响整个钻井工程质量。在水泥浆固化过程中,浆柱压力降低会增加上部套管的拉力,这是导致油、气、水窜及套管早期损坏的主要原因。设计了水泥浆固化过程中套管载荷测试的实验装置,模拟井下不同工况,研究了水泥浆密度、水泥环长度、添加剂以及地层环境等因素对套管顶部应力的影响,得出套管轴向拉力随水泥浆凝固时间增长先增加后降低、最后稳定的规律,为水泥浆体系配方优选、改进注水泥施工工艺等提供了参考。

Experimental study on relationship between weight losing of slurry by curing and casing axial tension

Slurry curing is one of the key parts of cementing process. The quality of slurry curing directly impacts the cementing quality, and then impacts the quality and cost of the whole drilling project. With the slurry curing, the pressure of slurry column would decrease, and it leads to the tension increase of the top casing, which is the main issue that causes the crossflow of oil, gas, or water, and also the early breakdown of casing. The experimental equipment was designed for testing casing load during the process of slurry curing. Through the simulation in different downhole conditions, it was studied that the impact of slurry density, cement length, addition agent, and reservoir property on the tension of the top casing. The rule was drawn that the casing axial tension would increase early and then decrease, and finally get stable, with the increase of the slurry curing period. The study could be a reference for the composition selection of slurry system and the improvement of slurry injection technique.