水泥环径向膨胀收缩实验研究

Study and Experiment on Radial Expansion and Contraction of Cement Sheath

固井水泥环径向膨胀收缩特性是影响固井界面胶结质量的关键因素之一。围绕水泥环在实际工况下膨胀收缩特性测试的技术难题,通过对测试仪釜体的升级改造,使测试仪不仅具备了传统方法测试水泥石轴向膨胀收缩的能力,而且具备了水泥环径向膨胀收缩的测试能力。应用固井水泥环径向膨胀收缩评价装置和评价方法,对川渝地区在用的韧性防窜水泥浆体系和柔性自应力水泥浆体系的膨胀收缩特性进行评价,找出了水泥浆体系的体积变化特性。同时,在不同温度压力下,对水泥浆的膨胀收缩临界点测试,为不同井段的水泥浆设计时的体系选用提供了重要的实验依据,为保障川渝油气田固井质量提供参考。

The radial expansion and contraction of cement sheath in oil and gas wells is one of the key factors affecting the bonding quality of the interfaces between casing string,cement sheath and borehole wall.To overcome the technical difficulties in testing the expansion and contraction characteristics of cement sheath in working conditions,the autoclave of the tester was modified and restructured to make the tester capable of measuring both axial(conventional tester)and radial expansion and contraction of the set cement.Using this new equipment,the tough anti-channeling cement slurry and the flexible self-stressing cement slurry presently in use in the Chuan-Yu area were evaluated for their expansion-contraction characteristics.The volumetric change characteristics of the cement slurry was found using the new tester and the evaluation procedure.The critical points of expansion and contraction of the cement slurry at different temperatures and pressures can be measured and used as important experimental data for selecting different cement slurries for different sections of the well.The new equipment and the data obtained with it have provided a reference for ensuring the job quality of well cementing in the Chuan-Yu area.