Analysis and Calculation of Threshold Pressure Gradient Based on Capillary Bundle

Table 3

The threshold pressure gradient of cores with various permeability.

Core number	Permeability, 10^−3 μm^2 (md)	Minimum threshold pressure gradient (MPa/m)	0.1–0.6 mL/min, threshold pressure (MPa/m)	0.1–0.6 mL/min, start permeability (md)	Threshold pressure gradient before the velocity sensitive (MPa/m)	Start permeability before the velocity sensitive (md)
P11	1.97	0.3205	3.504	0.440	22.246	0.420
P12	2.39	0.4209	1.711	0.561	19.572	0.697
P13	3.45	0.3383	2.559	0.546	18.515	1.154
P14	8.93	0.0626	0.576	0.166	—	—
P15	9.96	0.0495	1.138	0.197	3.843	4.216
P16	11.81	0.0161	0.450	0.092	—	—
P17	14.96	0.0521	0.324	0.185	1.816	6.661
P18	26.1	0.0299	0.213	0.073	—	—
P19	28.91	0.0198	0.290	0.062	—	—
P20	31.07	0.0276	0.484	0.160	1.179	16.582