Tungolskoye Oil Field
The Tungolskoye Oil Field is located in the central part of Licence 61. This structure was initially delineated by seismic data in
The Tungolskoye No. 1 well discovered oil on the structure in 1973. The well tested oil from the Upper Jurassic (J1) reservoir with initial flow rates of 52.8 m3/day (332 bopd) through a 12 mm choke. Reservoir pressure is 262 atm. The specific gravity of the oil is 0.825 g/cm3 or an API gravity of 40 degrees.
All of the vintage seismic data over the Tungolskoye structure has been reprocessed and reinterpreted by PetroNeft, and new high resolution CDP seismic data was been acquired over the feature during the winter of 2005/2006 and additional infill lines were acquired during the winter of 2006/2007.
PetroNeft drilled one further delineation well, Tungolskoye No. 4, on the feature commencing the winter of 2006/2007. The well had 15 metres of net oil pay in the J1 interval based on the core data and independent log interpretations and the well initially tested an inflow of 40 bopd. However, due to mechanical problems the Company was unable to achieve a representative flow test from the interval. The well was subsequently sidetracked to re-access and fully test the relevant reservoir interval. The side-tracked well bore successfully penetrated the reservoir about 100 metres to the east and 5 metres structurally higher than the vertical hole. However, the Company still had mechanical problems with the testing. The well was subsequently suspended in order to move the exploration rig to the West Korchegskaya location while winter roads were in place.
Based on the results to date the reservoir appears tight/damaged at this particular well location and will need to be fracture stimulated for proper assessment. Testing of the Tungolskoye No. 4 well will be completed as part of the Lineynoye and West Lineynoye Phase 1 development project when PetroNeft will have its own frac crew and work-over rig in the field. This will allow for the testing to be completed in a proper and cost effective manner.
Ryder Scott estimates the field to have SPE proved and probable (2P) reserves of 14.77 million barrels of oil. Russian C1 + C2 reserves are 16.07 million barrels.
