The properties of two copolymeric particulates used for oilwell in-depth performance control were investigated systematically. The lab-scale studies showed that the average diameter of these particulates (E5 and G6) is 77.76 mu m with the standard deviation of 2.16%. The two particulates exhibit good dilatability when immersed in 20 X 10(4) mg/L NaCl solution. Their capability of water retention (150 days) was 90% at 80 degrees C. In addition, they exhibited good injectivity, driving performance and plug, and satisfied toughness index. The diffluence experiments confirmed that the coefficient of the profile modification were 85.7, 98.7, 86.1, and 98.1% when the permeability levels were 4.05 and 15.0, respectively. When using the two particulates, the average recovery ratio can reach 21%. The procedures mentioned earlier could be used as industry criteria to evaluate all kinds of particulate used as in-depth performance controllers. (c) 2006 Wiley Periodicals, Inc.