This article shows the very first experience in Russia of using new Schlumberger technology of matrix acidizing of carbonate formation – MaxCO3 Acid System*.

Uniform stimulation, optimum wormhole penetration, lack of residual contamination etc. are main indicators of successful matrix acidizing. Comprehensive approach and optimal solution are required to design successful matrix acidizing.

Acid treatments of critical matrix can be complicated in gas wells with a net pay up to 200 meters. The main feature of AGKM wells is the presence of the tailpipe. It overlaps production zone up to 80–90% and closes direct access to the middle and upper production intervals. That forces to perform acidizing through the bottom zone of formation and lift up the treating fluid along the annulus. It is impossible to do without effective diverting taking in consideration thief zones and natural fractures which are normal for carbonate formation. The unique formation properties are addition complicates beside wells construction that apply additional limitation to the technologies used, materials and equipment. Formation C2b consist high sour gases concentration it is up to 27% and CO2 up to 15%. BHST about 110degC and abnormally high formation pressure which is up to 612 bars.

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