Diagnostic Study of Excessive water production in Aswad Oilfield, Libya

Water production in oilfields is a complicated issue which has a serious economic and environmental concern. The treatment and disposal of produced water cost millions of dollars for a single field. On the other hand, high water production causes a severe reduction in oil production. This paper focuses on diagnostic plots to identify the mechanism of water production. Aswad oilfield produced with high water rate and its status as water flooded the reservoir, so diagnosing reasons for producing high water is by using the most common methods such as Chan plot well by well. The first method is to investigate the water problem by plotting WOR and derivative of WOR' then compare the plot with typical Chan plots to identify the reason for water production, which applied as a field and on three selected wells (B06 – B09A- B-11). The rate of water cut is 88% per day. Based on production data and previously applied techniques, this work identified water problems by using water diagnostic plot Chan plots. The methodology of this work initiated with the study the performance of Aswad field by analyzing the history of production. The work shows that multilayer channeling is the main reason for water production in wells with high permeability. Finally, Aswad field is water flooded due to high water cut that produced from reservoir that supported by water injection from early period of the field. Diagnose the study of water production behaviour is to optimize the reservoir productivity after controlling the excessive water production. The wells should be the primary candidate for water control