Method for removing scale via a liquid membrane in combination with an amino carboxylic acid and a catalyst

A liquid membrane method for removing barium sulfate scale contained within wellbores and equipment affixed thereto used in the production of hydrocarbonaceous fluids comprising:

• a) removing hydrocarbonaceous fluids from said wellbore and equipment;
• b) preventing the intrusion of additional hydrocarbonaceous fluids within said wellbore;
• c) placing within said wellbore and equipment an emulsion containing an external aqueous phase and an immiscible liquid hydrocarbonaceous membrane phase enveloped around droplets of an internal aqueous phase;
• d) solubilizing scale into scale-forming ions from said wellbore and equipment via said external aqueous phase which consists essentially of:
• i) an aqueous solution consisting essentially of a pH of from about 8 to about 14;
• ii) a first complexing agent selected from a member of the group consisting of aminocarboxylic acid or polyamines, salts and mixtures thereof in an amount of at least from about 0.1 to about 1.0M;
• and
• iii) a catalyst in an amount of at least from about 0.01 to about 0.5M selected from a member of the group consisting of flouride, persulfite, persulfate, dithionate, hypochlorite, formate, salicylate, aminoacetate, glycolate, or thioglycolate anions and mixtures thereof, having an ionization constant of less than about 10.sup.-2 K.sub.a <10.sup.-2 which acts with said first complexing agent to substantially enhance said agents ability to solubilize scale;
• e) transferring said ions from said external aqueous phase into said hydrocarbonaceous membrane phase which contains a second complexing agent for reacting with said scale-forming ions which is stronger than said first complexing agent;
• f) transferring and concentrating said scale-forming ions from said hydrocabonaceous membrane phase into said internal aqueous phase which has a stronger third complexing agent than said second complexing agent;
• and
• g) transferring said scale-forming ions from said external aqueous phase into said hydrocabonaceous membrane phase which ions are then transferred from said hydrocarbonaceous membrane phase into said internal aqueous phase where said ions are accumulated and concentrated which causes scale to be removed from said equipment and wellbore within a substantially reduced time period than is possible with said first and third complexing agents alone.