Dissolving barium sulfate scale with aqueous solutions of bicyclic macrocyclic polyethers and organic acid salts

A process for dissolving barium sulphate solid from a remote location into which fluid can be flowed which process comprises:

• flowing into said remote location and into contact with the barium sulphate an aqueous liquid consisting essentially of water, a bicyclic macrocyclic polyether, an alkali metal salt of a polycarboxylic organic acid in a proportion which is not more than that of said polyether but is sufficient to catalytically increase the rate at which barium sulphate is dissolved and enough dissolved alkaline inorganic alkali metal or ammonium material to provide a solution pH of at least about 8;
• using as the bicyclic macrocyclic polyether a compound of the formula:
• ##STR10## wherein (a) A represents a hydrocarbon radical having up to 12 carbon atoms and D represents a member of the group consisting of oxygen atoms, sulfur atoms, hydrocarbon radicals having up to 12 carbon atoms and .dbd.N--R.sup.2 groups in which R.sup.2 represents a hydrogen atom, hydrocarbon radical having up to 12 carbon atoms, a hydrocarbonsulfonyl radical having up to 12 carbon atoms, an alkoxycarbonyl radical having fewer than 5 carbon atoms, an alkoxycarbonyl-methylene radical having fewer than 5 carbon atoms or a carboxymethylene radical, (b) at least two of the D's represents a member of the group consisting of sulphur atom or .dbd.N--R.sup.2 group, (c) m, n and p are integers from 0 to 5 inclusive, and (d) the bicyclic macrocyclic polyether contains an intramolecular cavity which is preferentially receptive to the cations of the alkaline earth metals.