Method for removing alkaline sulfate scale

摘要

The present invention relates to the use of low frequency sonic energy within the range of 1.25 to 6.5 KHz, preferably less than 2.0 KHz and most preferably 1.25 KHz, for enhancing the dissolution of alkaline earth metal scales from well bores using a scale-removing solvent comprising an aqueous alkaline solution having a pH of about 8 to about 14 and containing EDTA or DTPA and a catalyst or synergist, preferably an oxalate anion. When the scale deposit is contacted with the scale removing solvent while simultaneously transmitting low frequency sonic energy through the solvent, substantially more scale is dissolved at a faster rate than previously possible.