Preparation and Performance Evaluation of Polymeric Microspheres Used for Profile Control of Low-Permeability Reservoirs

Table 1

Average particle sizes of the polymeric microspheres.

Hydration time (day)	Average particle size (nm)				PDI (polymer dispersion index)
	First test	Second test	Third test	Average	First time	Second time	Third time	Average
Initial	380.4	371.2	387.3	379.6	0.622	0.737	0.641	0.667
1 d	2534	2515	2658	2569	0.475	0.646	0.278	0.466
5 d	6460	6713	6569	6581	0.287	0.206	0.218	0.237
10 d	7396	7302	7224	7307	0.331	0.297	0.312	0.313
15 d	7826	7545	7569	7647	0.238	0.249	0.273	0.253
20 d	8256	7991	8019	8089	0.281	0.34	0.342	0.321