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

Table 2

Basic performance test of drilling fluid.

Density/g·cm^−3	Hours of aging at 100°C	Apparent viscosity/cP	Plastic viscosity/cP	Yield point/Pa	Gel strength/Pa	Filter loss (API)/mL
0.93	0	63	16	24.02	1.00	3.6
	16	43	16	13.80	1.48
0.86	0	83	27	28.62	0.86	2.8
	16	70	41	14.82	0.58
0.75	0	122	38	42.67	0.93	2.4
	16	99	29	35.77	0.95