Patent ID: 6227296
Filing Date: 2001-05-08
Classification: E21B

Abstract:
A method for reducing the water saturation in the near-well region of a subterranean formation having a well, said near-well region containing at least some water and having a corresponding first water saturation, S.sub.w1, said method comprising:a) selecting a displacing phase, wherein said displacing phase is selected to have a capillary number, N.sub.CA, with respect to the water sufficient to cause a reduction in residual water saturation in the portion of the subterranean formation contained in the near-well region;b) introducing said displacing phase into said near-well region;c) displacing at least a portion of the water from said near-well region; andd) thereby producing a second water saturation, S.sub.w2, corresponding to N.sub.CA, which is less than S.sub.w1wherein said capillary number for a given displacing phase, N.sub.CA, is determined by the following equation:N.sub.CA =(V.sub.DP.times..mu..sub.DP)/(IFT.sub.DP.H2O)whereV.sub.DP is the interstitial velocity of said displacing phase,.mu..sub.DP is the viscosity of said displacing phase, andIFT.sub.DP.H2O is the interfacial tension between said displacing phase and water.