Progressing cavity pump anti-scaling techniques in alkaline-surfactant-polymer flooding in the Daqing Oilfield

To solve the severe PCP scaling during the ASP flooding in the Daqing Oilfield, PCP anti-scaling and lifting techniques are studied. This paper comprehensively analyzed the reasons and principles of PCP scaling during the ASP flooding, and the common failure modes in PCP wells by scaling. The fit accuracy between PCPʹs rotor and stator dropping, frictional behavior irregular changing and severe abrading by scaling are the main reasons for the increase of the PCPʹs failures. Based on these, a comprehensive anti-scaling lift technique for PCP wells was proposed including PCP rotor/stator wring optimization, instrument material surface modification, and chemical clear/anti-scaling technique. By the end of 2010, the comprehensive methodology has been applied in 216 PCP producers 425 times, the average running lives of PCP producers in the ASP flooding were improved from less than 100 days to 298 days after applying the above PCP anti-scaling methodology, the longest one is 1 370 days.