Abstract
ASP flooding in Daqing oilfield commenced from 1980s. To date, industrial pilot tests have been carried out in three blocks. The averaged recovery was increased by 20%. On the other hand, scaling issue caused high frequent pump failures. Large amount of scale building up in the producers wellbore and downhole equipments with high speed, which resulted in the averaged running life of lifting system decreased from 599 days of water flooding period to 60 days. Further more, some producers’ running lives were only around 30 days, leading to higher production cost and lower production rate as well.
Study indicated that, the scaling principle and scale composition in producing wells differed from each other and was difficult to be predicted accurately. In this study, after tracking and measuring the ion in produced fluid for the whole process from water flooding, polymer flooding to ASP flooding and analyzing composition of the scale on different parts of scaling well, the criterion and distinguishing chart of scaling tendency had been set up initially. The criteria were applied in 102 wells in ASP flooding area, the accordance rate was more than 90 percent. Based on that, scaling inhibition technology was timely performed for predicted scaling wells, and the running lives were increased from 40 days to above 200 days. This paper presented the process of the study and is greatly helpful for APS flooding in commercial scale.
