Unlocking Undrained Oil through Integrated Reservoir Dynamic Model in Matured Waterflood Field, Offshore North West Java

Abstract

After 40 years of production, more than 40% of the E-22 reservoir hydrocarbon in place has been recovered through various  mechanisms including natural depletion, gas lift implementation and waterflooding. Further development of the reservoir  requires a reliable tool to identify the area of remaining oil saturation. Maximizing the recovery further has always been the stakeholder requirement. Identifying the remaining oil accumulation properly is one of the key for future development  optimization -either through new infill wells, workover existing completion or rig less intervention- and yet it has many challenges to have such expensive information. Reservoir dynamic model may provide fluid movement and hydrocarbon saturation in the reservoir. However, the result is as best as the input data and production/injection history matching. The reservoir dynamic model was revisited with the integration of 3D seismic, sand ridge concept, petrophysical analyses and new rock type definition/distribution. The work has a positive impact on the reservoir model history matching which later on provide better insight on the oil and water movement in the reservoir. Three sidetrack development wells are executed to achieve production target set by stakeholders. The open hole logs from all sidetrack wells suggest undrained oil with pay thickness between 15-20 ft, as anticipated from the dynamic model. All wells were completed as single string completion with selected perforation. The workover job includes squeeze and perforation in order to maximize oil production from the undrained interval. The overall result is very positive, additional 1000 bopd is booked from these activities.