Ascent Completes First Phase of Ops at Petisovci Well
Ascent has successfully completed the first phase of operations on the Pg-11 well in the Petišovci Project ('the Project') in Slovenia, where the Company has a 75% interest. The primary objectives of the well have been satisfied with gas confirmed by logs in all of the six Middle Miocene Badenian reservoirs. In addition, gas and condensate were sampled from the Lower Miocene Karpatian reservoir and gas flowed for the first time from the shallowest 'A' sands. The next phase of the operations depends on the analysis of the log and core data and it is planned that the Crosco Cardwell-1 rig will remain on location so a horizontal production sidetrack can be drilled.
- All six Middle Miocene Badenian reservoirs confirmed to be gas bearing, underpinning commercial potential of the Project;
- Gas and condensate sampled and flared from Lower Miocene Karpatian reservoir;
- 'A' sands flowed gas to surface during an open hole test;
- The E and F sands and the Lower Miocene Karpatian reservoir all encountered in a structurally high position;
- Three 18m core samples recovered from each of the A, D and E sands and state-of-the-art logging data acquired across the 1,000m prospective horizons. This data is now being analyzed to determine the optimum exploitation strategy;
- Pg-11 was the first well to be drilled in 22 years on the Petišovci-Lovaszi project area which has P50 estimate of gas-in-place of 412 Bcf (11.7 Bm3; 68.7 MMboe); and
- The Karpatian reservoir is likely to contribute to an increase in the gas-in-place estimates.
Ascent's Managing Director, Jeremy Eng commented, "The results from the Pg-11 appraisal well, which reached its planned depth of 3,050m last week, have exceeded our expectations. These results substantially de-risk the Project and underpin its commercial potential. Gas was logged in all six reservoir intervals and as an added bonus gas is present in the unexploited and apparently naturally fractured Lower Miocene Karpatian reservoir, which we hope will contribute to an increase in the current P50 estimate of gas-in-place.
"The new data generated from the Pg-11 well supplements the recent 3-D surveys recorded across the whole 200km2 project area and enables us to move forward with the second phase of the well program focused on a horizontal production side track. Facilities design studies are now being completed for the redevelopment program and we believe that there is the potential to commence production within a year."
The Petišovci-Lovászi Project straddles the Slovenian Hungarian border and has an area of approximately 200km2. The Pg-11 well reached a total depth of 3,050m on 7 February 2011. It drilled through the six targeted gas reservoir intervals and in each interval gas shows with components in the range of CH4 (Methane) to C5H12 (Pentane) were recorded. Full sized cores were recovered, 18m long, from three of the reservoir intervals and these are now being analyzed for a full range of reservoir parameters.
Two open hole tests were also run: the first in the shallowest 'A' sand produced a flow of gas estimated to be 600m3 per day (21.2 Mscfd), while the second test in the 'D' sand was terminated early with indications that the testing tool had become plugged. Both tests confirmed the expected pressure gradient that ranges from 1.25SG in the shallowest interval to approximately 1.6SG in the deepest 'F' sand. Because of this pressure transition, which reached 1.78SG in the Karpatian, testing of intervals below the 'D' sand were not contemplated and recovery of the test tools after the 'D' sand test proved difficult. Below the 'F' sand, 58m of the Karpatian formation with a higher 1.7 SG pore pressure was drilled and strong gas shows were observed throughout. During circulation after logging, gas from the Karpatian formation was flared and condensate samples were collected. At this time the drill string became stuck and over 1,100m of drill pipe remains in the well. However this will not prevent drilling a horizontal side track.
Logs have been run across the six reservoir intervals and the Karpatian and preliminary results indicate good gas saturations throughout the combined gross thickness of 1,000m. The drilling and log data from the Karpatian formation indicate a naturally fractured and porous formation and a nearby well showed that this formation can be over 200m thick. It is likely that this horizon will contribute to an increase in gas-in-place estimates.
The Pg-11 well is the first well to be drilled in the Petišovci Miocene reservoirs in 22 years. The primary objective for the well, apart from the confirmation of gas in this part of the field, was to acquire state-of-the-art data and reservoir samples to determine how and if we enable the latest hydraulic fracturing techniques to be applied to the redevelopment of these gas reserves. In recent years, technological advances have enabled the development, firstly of tight gas reservoirs and latterly of shale gas reservoirs. The Petišovci-Globocki gasfield, without the benefit of new technology, produced approximately 240 mm3 (8.5 Bcf) of gas during the 1980s, mainly from two wells. This gas represented only 2% of the gas-in-place of 11.7 Bm3 (412 Bcf; 68.7 mmboe) as evaluated by independent technical auditors RPS Energy.
As an extension to its work on the independent gas-in-place report, RPS Energy has forecast the productivity of a horizontal sidetrack. The new data will enable its reservoir engineering simulations to be fine-tuned. Generally, reservoir quality improves with depth and the deeper reservoirs have a higher pressure. The deeper reservoirs are therefore more likely to produce at commercial rates from simple un-stimulated horizontals whereas the shallower reservoirs are expected to require fracture stimulation. The integration of the new data into the geological model is needed to accurately predict well performance and the results of the seismic reprocessing will determine the optimum trajectory. From the existing wells, the deeper, higher pressured intervals, have exclusively contributed to the historical production.
Ascent is in discussions regarding the appointment of a specialist technical adviser for tight gas sand developments and has access to the extensive technical resources of EnQuest plc, now a major shareholder in the Company, to optimize the future redevelopment plans for the Project.
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