Polymer Drilling Fluid with Micron-Grade Cenosphere for Deep Coal Seam

Table 5

The evaluation of sedimentation stability (method of using long plastic tube).

Time/h	0	24	48	72	96	120	144
Phenomenon
Result	Upper density (144 h): 0.849 g·cm^−3, lower density (144 h): 0.870 g·cm^−3