Patent ID: 7854263
Filing Date: 2010-12-21
Classification: C04B,C09K

Abstract:
1. A method for removing an oil based fluid mud cake from a well wall, comprising the steps of: providing a well defined by a well wall and having an oil based mud cake on the wall; and exposing the mud cake to a surfactant blend comprising a first non-ionic surfactant having a hydrophilic-lipophilic balance of between about 10 and about 15, a second non-ionic surfactant having a hydrophilic-lipophilic balance of between about 2 and about 6, and an anionic surfactant, wherein the first and second non-ionic surfactants comprise ethoxylated tridecanol; whereby the surfactant blend changes wettability of solids in the mud cake and forms an emulsion with oil from the mud cake.