一种改进的低密度水泥浆性能测试方法

A Modified Testing Method for Low Density Cement Slurry

目前中国低密度水泥浆主要参照常规固井水泥浆的性能测试方法,但是其主要针对一般井况和一般的水泥浆使用条件。对于深井、超深井或长封固段井等,如果施工过程中出现水泥浆密度波动,实验温度预测误差,注水泥过程中紧急停泵等,现有低密度水泥浆的测试方法可能会存在一些不足。因此,提出了一种改进的低密度水泥浆性能实验项目:密度高点稠化实验、密度低点稳定性和抗压强度实验、温度波动稠化实验、停机稠化实验、升降温稠化实验以及相应的测试方法,通过实验可以模拟水泥浆密度波动情况、实际井底温度与实验温度出现误差的情况和注水泥过程中出现停泵等施工突然中断的情况等,为固井实验研究人员提供参考。

In deep well, ultra deep well or well with long cementing length, changes in density of cement slurry, errors in temperature prediction, and emergency shut-off of pumping are frequently encountered, resulting in discrepancies in measured cement slurry properties and the actual cement slurry properties downhole. There are some shortages in the presently used method of cementing slurry measurement, and a modified method is presented. The new method includes the thickening test at the highest slurry density, stability test and compression test at the lowest slurry density, thickening test under changing temperatures, thickening test when cement slurry is not flowing, thickening test when temperature is increasing and decreasing respectively, and testing method thereof. These tests are able to simulate changes in density of cement slurry, discrepancy between actual bottom hole temperature and temperature under which laboratory experiments are done, and sudden stop of pumping during cementing.