Water production started increasing from some Bapetco's oil/gas reservoirs with a subsequent drop in hydrocarbon production. Water movement in the reservoir was not well understood, and it was not clear whether zones of high hydrocarbon saturation still existed. Therefore, a saturation distribution study was initiated with the objective of increasing oil/gas production while decreasing water production. The geology of the fields was examined to select key wells for determining the water saturation using thermal neutron decay time logs. In wells with existing TDT* logs, the time-lapse technique was used to determine the change in saturation. In wells without existing TDT logs, the open hole saturation just after drilling was used to determine the change in saturation. The saturation changes were incorporated with the field geology to provide a good understanding of saturation over the entire reservoir. The integration of production log results, production geology and simulation data has led to a new picture. Water shut off using through-tubing bridge plugs was applied as a solution for the increasing water production. Other water shut off techniques were also considered. Unflushed zones were perforated to increase oil production. Using an updated simulation model, horizontal wells were planned to target unswept zones. One horizontal well was drilled so far with good result. The paper presents the successful integration of at least four different techniques in order to optimize reservoir performance.

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