BADAMI FIELD: RECENT ADVANCES IN UNDERSTANDING AND MANAGING A CHALLENGING BROOKIAN RESERVOIR - AN INTEGRATED GEOLOGIC AND ENGINEERING APPROACH

BREDAR, William L., Anchorage, AK 99507, [email protected] and WHITNEY, John A., Anchorage, AK 99515

The Badami reservoir is a low net:gross, compartmentalized and moderately overpressured Paleocene age turbidite sandstone on Alaska's Eastern North Slope. There are a total of 13 wells and 18 reservoir penetrations. Original reserves were estimated at 120 MMB assuming a tertiary EOR flood. Cumulative production is 4.6 MMB utilizing primary depletion and produced gas injection. Oil production peaked soon after start-up at 17 MBD and dropped precipitously resulting in a suspension of development drilling. No original gas cap or water leg has been encountered. The 3 major challenges are the volume of net sand, its connectivity, and variable oil quality. Production was recently resumed after a 2 year shutdown. Seismic and well control indicate a stacked lobe system. 4 key facies are recognized: amalgamated pay, bedded pay, thin bedded pay, non-pay. Permeability in the amalgamated and bedded sandstones averages 100 mD while thin bedded sandstones average 10mD. Porosity averages 19%. Compartments are apparent on 5 scales: fan system, fan lobe, nested channel complex, individual channel, individual bed. All original well designs were near vertical and utilized openhole multi-lateral slotted liners or frac'd conventional completions to access stacked sands and thin bedded pays. Development drilling proved less sand presence in upper lobes and rapid lateral facies changes. Reservoir pressures acquired in 2005 show compartment re-charge/re-equilibration at slow but measureable rates. Material balance calculation shows one well to be in contact with over 20 MMB. These data, along with a revised history matched sector reservoir model, which utilized reflection seismic amplitude data for porosity realization, have led to the conclusion that the reservoir is heavily baffled but not completely sealed. A new schedule of paraffin and asphaltene removal from wellbores has resulted in improved well flow rates. Current field rate from 4 producers is ~ 2,000 BOPD. A horizontal well design which can link compartments in the basal lobes of the Badami Sands sequence should provide better access to Badami's oil resources. Re-development is being considered.