Operational Update

Petroneft Resources PLC 19 June 2007 19 June 2007 PetroNeft Resources plc Operational Update PetroNeft Resources plc ('PetroNeft' or 'the Company'), 100% owner of Stimul-T, which is the sole owner and operator of Licence 61, Tomsk Oblast, Russian Federation, is pleased to provide this update on the progress on its 2006/07 three well drilling programme. • Positive initial drilling results from Tungolskoye No. 4 delineation well. • High impact exploration well Lineynoye No. 7 has been spudded. Tungolskoye No. 4 Well The Tungolskoye Oil Field is located in Licence 61 in the Tomsk Region of the prolific Western Siberian Oil and Gas Basin. Discovered in 1973, Ryder Scott petroleum consultants estimate 2P reserves of 17.92 million barrels of oil for the field. • The Tungolskoye No. 4 well was spudded on 16 May 2007 and reached Total Depth of -2,900 metres subsea on 15 June. • Oil was confirmed in the primary reservoir interval comprising over 15 metres of continuous net pay in the Upper Jurassic Vasugan Formation. This represents the single best reservoir interval drilled to date on Licence 61. The entire reservoir interval was successfully cored and these cores are currently being analysed in detail. • The Base Bazhenov Formation was penetrated at -2,505 metres subsea which is in good agreement with the seismic interpretation prior to drilling the well. The data indicates that the oil water contact (owc) is consistent with the current field wide owc at -2,526 metres subsea. Geophysical logging and initial petrophysical analysis has now been completed and preparations are now underway to carry out flow tests on the well to determine its productive capacity. Results will be published as soon as they are available. Lineynoye and Tungolskoye Drilling Programme The current appraisal drilling programme which comprises two wells, the recently completed Lineynoye No. 6 well and Tungolskoye No. 4, is designed to confirm prior reservoir data in the Lineynoye and Tungolskoye fields and to provide further input into a Final Development Feasibility Study. The programme also includes a high impact exploration well, Lineynoye No. 7, on the West Lineynoye Prospect. These results will also be incorporated into the Final Development Feasibility Study expected to be completed in late 2007. West Lineynoye Prospect - Lineynoye No. 7 Well The Lineynoye No. 7 Well was spudded on 18 June 2007. West Lineynoye, a high impact prospect, is estimated by Ryder Scott to contain Possible Reserves of approximately 67 million barrels of oil. The principal target horizons for this well are Upper Jurassic sandstone reservoirs starting at a depth of about -2,375 metres subsea. The total planned depth for the well is approximately -2,750 metres and it is anticipated that the well will be drilled, logged and tested within approximately 70 days of commencement. Dennis Francis, Chief Executive Officer of PetroNeft Resources plc commented: 'We are delighted with the initial results from the Tungolskoye No. 4 well. This result confirms the presence of a significant and continuous reservoir interval and supports the current structural and hydrodynamic interpretation of the field. The 15.2 metres of continuous net pay represents the single best reservoir interval drilled to date in the Licence area and is an important input into our ongoing development and production feasibility planning work. We look forward to positive flow test results from Tungolskoye No. 4 and the drilling of Lineynoye No. 7 which could bring significant new reserves into our portfolio.' For further information, contact: Dennis Francis, CEO, PetroNeft Resources plc +1 713 988 2500 Desmond Burke, Director Investor Relations, PetroNeft Resources plc +353 52 53226 John Frain/Brian Garrahy, Davy +353 1 679 6363 Nick Elwes/Paddy Blewer, College Hill +44 207 457 2020 Damien Mauvais, Natixis +44 207 220 5184 The information contained in this announcement has been reviewed and verified by Mr. Dennis Francis, Director and Chief Executive Officer of PetroNeft, for the purposes of the Guidance Note for Mining, Oil and Gas Companies issued by the London Stock Exchange in March 2006. Mr. Francis holds a B.S. Degree in Geophysical Engineering and a M.S. Degree in Geology from the Colorado School of Mines. He has also graduated from the Harvard University Program for Management Development. He is a member of the American Association of Petroleum Geologists and the Society of Exploration Geophysicists. He has over 34 years experience in oil and gas exploration and development. Glossary of Key Technical Terms Bazhenov Formation - Organic rich shale of Upper Jurassic age that is both a major source rock for oil and cap rock in the West Siberian Oil and Gas Basin. The base of the formation is a continuous and reliable seismic marker throughout the basin. J11 and J12 Sandstones - Stratigraphic units in the top part of the Vasyugan Formation of Upper Jurassic age in the West Siberian Basin. The Vasugan Formation underlies the Bazhenov Formation and the J11 and J12 sandstones are normally of reservoir quality in the region with sufficient porosity and permeability to store and transmit hydrocarbons. Oil Water Contact - A bounding surface in a reservoir above which predominately oil occurs and below which predominately water occurs. Subsea or Relative Depth - represents the vertical depth of the well bore below a reference datum taken as mean sea level. In mathematical terms this depth is equal to the True Vertical Depth (TVD) of the wellbore minus the elevation of the drill floor or measurement reference point. Forward Looking Statements This announcement contains forward-looking statements. These statements relate to the Company's future prospects, developments and business strategies. Forward-looking statements are identified by their use of terms and phrases such as 'believe', 'could', 'envisage', 'potential' 'estimate', 'expect', 'may', ' will' or the negative of those, variations or comparable expressions, including references to assumptions. The forward-looking statements in this announcement are based on current expectations and are subject to risks and uncertainties that could cause actual results to differ materially from those expressed or implied by those statements. These forward-looking statements speak only as at the date of this announcement. End This information is provided by RNS The company news service from the London Stock Exchange
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