The Ashalchi natural bitumen field is developed with application of SAGD method, which involves drilling two horizontal wells at a distance of 5 meters vertically between them: the upper well is for injection steam, and the lower well is for production.
The deposit is underlain by waters, which have a high concentration of calcium carbonate. Steam injection and intense production cause deposition of calcium carbonate in bottom hole of the well, and directly in a slot filter and operating components of ESPs. It results in the loss of production, which is connected with failure of the ESP.
"TatNIPIneft?? developed a special technology of treating wells with 8% inhibited hydrochloric acid for cleaning the bottom zone of the well and the slotted filter from calcium carbonate. Acid composition was matched with a concentration that did not occur in the processing of metal corrosion. This technology requires workovers and using coiled tubing technology. As the analysis shows, this method is very expensive. Besides, we have to stop well for 3 to 4 days and there is a loss of oil production.