| abstract |
A method of removing an iron sulfide scale from a surface in fluid communication with a wellbore and/or subterranean formation comprising contacting the iron sulfide scale on the surface with a composition to dissolve the iron sulfide scale in the composition. The composition comprises (a) at least one chelating agent selected from the group consisting of DTPA, EDTA, HEDTA, GLDA, CDTA, and MGDA, and salts thereof, and (b) at least one converting agent selected from the group consisting of potassium carbonate (K 2 CO 3 ), potassium formate (HCOOK), potassium hydroxide (KOH), potassium chloride (KCl), cesium formate (HCOOCs), and cesium chloride (CsCl). In the composition, the weight ratio of (a):(b) lies in the range 7-60:2-20. |