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PetroNeft flows oil at Tungolskoye Western Siberia well

14th October 2014

The vertical pilot hole of the Tungolskoye No. 5 (T-5) well has been successfully drilled, and the Upper Jurassic J1 oil reservoir horizon was intersected at -2,495.8 metres true vertical depth subsea (TVDSS), which is approximately 11-metres high to the T-1 well to the south

PetroNeft flows oil at Tungolskoye Western Siberia well
Preliminary evaluation of the logs indicates that the J1 interval consists of at least 8.2 metres of net pay

"We are pleased with the results of the T-5 well so far and the flow rate achieved,” said Dennis Francis, chief executive officer of PetroNeft Resources.

“The well has confirmed both the structural interpretation as well as a good reservoir interval and initial test. We look forward to completing our first horizontal well at Licence 61 and continuing our on-going production drilling work at Arbuzovskoye."

The results are consistent with expectations and confirms the structural interpretation of Tungolskoye. Preliminary evaluation of the logs indicates that the J1 interval consists of at least 8.2 metres of net pay. An open-hole test was conducted over this interval and tested at a pro-rated inflow of 100bopd un-stimulated.

The part of the well below about 800 metres will now be sealed with cement plugs to isolate the reservoir before drilling down at a different angle to properly position a new horizontal section. The well will first be drilled down to a depth of approximately -2,490 metres TVDSS and then casing will be set.

Baker Hughes will then take over in order to drill the horizontal section in the reservoir. The process is expected to take approximately 3 to 4 weeks, after which the horizontal section of the well will be tested.

The Arbuzovskoye 106 well is drilling ahead at more than 2,000 metres depth and is expected to be completed later this month.

The Tungolskoye Oil Field is located in the central part of Licence 61. This structure was initially delineated by seismic data in 1967-68. Additional seismic data was obtained in 1970-71. Further seismic surveys were run in 1993-1994.

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 for 30 minutes then the well started pulsating. Stabilised flow was achieved on a 3mm choke at 10.5 m3/day (66 bopd) with 20 % water. 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.

Beginning in 2012, PetroNeft entered into an agreement with TomskGeophysicalCompany (TGK) to reprocess and reinterpret all of the existing seismic and well data at Tungolskoye and Traverskaya. This was a very comprehensive report that was finished in March 2013. The new structural map at Tungolskoye shows a large portion (>10 sq kms) up-dip from the existing T-1 and T-4 wells which encountered thick oil pays with good non stimulated test results.



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