Patent ID: 6112814
Filing Date: 2000-09-05
Classification: C09K,Y10S

Abstract:
A method for cleaning a wellbore plugged with deposits comprising heavy hydrocarbonaceous materials and finely-divided inorganic solids, the method comprising:a) positioning a coiled tubing to extend from a surface into the wellbore;b) injecting a surfactant composition comprising an aqueous solution containing:1) about 0.1 to about 10.0 weight percent of an alkyl polyglycoside surfactant selected from alkyl polyglycosides containing alkyl groups containing from about 8 to about 19 carbon atoms and mixtures thereof;2) about 0.1 to about 10.0 weight percent of an ethoxylated alcohol selected from the group consisting of ethoxylated alkyl alcohols containing from about 6 to about 16 carbon atoms in the alkyl alcohol and from about 2 to about 6 ethylene oxide groups and mixtures thereof, and ethoxylated alkyl phenols containing from about 8 to about 14 carbon atoms in the alkyl group and from about 2 to about 8 ethylene oxide groups and mixtures thereof, and mixtures of the ethoxylated alkyl alcohols and the ethoxylated alkyl phenols;3) about 0.5 to about 10.0 weight percent of a caustic selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonium hydroxide and mixtures thereof; and,4) about 0.1 to about 6.0 weight percent of at least one alkyl alcohol containing from about 4 to about 6 carbon atoms; through the coiled tubing into contact with the deposits at a velocity sufficient to agitate a top layer of the deposits; and,c) circulating at least a portion of the surfactant composition through the wellbore.