Perpustakaan Digital ITB

Scale precipitation becomes an important issue in steamflood recovery technique. Thermal processing creates high temperature ambient and increase the potential for scale precipitation as the solubility is reducing as the temperature increase. In Dora field, this problem has become common since its early steamflooding development in 1985. Many acidizing stimulation acidizing has been conducted since then but no robust technical background for selecting the candidate of treatment. In the end, there are about 30 – 40% of unsuccessful acidizing jobs that are not necessarily to be executed. This research combined several completed studies that were conducted in 2000 & 2009. The focus items on acidizing selection candidate is back to the nature of water mineralogy as the basic element of scaling issue. The water mineralogy includes the ions Ca2+ and HCO3 -. Dora field produced from 3 main reservoirs, those are A, B and C. Each reservoir has similarities and particular distribution of the water mineral ion. One of methodology to understand the distribution of water mineralogy is by generating statistical analysis and production attribute mapping. The results indicated that most of reservoir has potential for having scaling tendency, but A reservoir having much carbonate which range on 600 - 1,550 mg/L, and also high content of total dissolved solids by 2,500 mg/L concentration (almost twice from the other reservoirs) which means that the potential of scaling precipitation is twice in A reservoir compare to another reservoir. In conclusion, the structured approach of acidizing candidate selection treatment should consider several parameters such as scale index, total dissolved solid, inflow/outflow issue, historical of acidizing that conducted in specific area, temperature and reservoir produced. The predictability can be considered from current total dissolved solid. However, dynamic data should be continuously taken in order to generate flow story of water mineral data. This could be the good input for further research development.