Sterling Reaches TD at Cladhan Appraisal Well

- Sterling Reaches TD at Cladhan Appraisal Well

Friday, June 03, 2011
Sterling Resources Ltd.
by SubseaIQ

Sterling announced the completion of drilling of the 210/30a-4X well on Block 210/30a in the United Kingdom North Sea. This is the fourth well (third side-track) drilled in the current four well campaign to further appraise the extent of the Cladhan reservoir.

The 210/30a-4X well was drilled in the most southern limit of the northern core area in a potentially separate channel, utilizing the Transocean Prospect rig. The objectives of the 210/30a-4X sidetrack well were to core the full reservoir section approximately one kilometer south and approximately 60 feet updip of the oil bearing 210/30a-4 well, and evaluate the southern fringe of the northern core area.

The 210/30a-4X well was drilled to a total measured depth (MD) of 10,614 feet encountering 171 feet gross, 105 feet net (vertical thickness) of high quality Upper Jurassic sands. Almost 180 feet of core was successfully recovered across the full reservoir section.

Petrophysical analysis of the interval showed five feet of oil-bearing sand at the top of the interval with an Oil-Down-To at 10,177 feet True Vertical Depth Subsea (TVDSS). An oil sample was obtained from the interval. A further 100 feet of water-bearing sand was encountered below thin shale which separates the top and bottom sands. A clear contact has not been observed although the top and bottom sands appear to be in pressure communication. The presence of a known Oil-Down-To bodes well for updip oil in other channels with the same pressure regime.

Generally, reservoir quality is very good with porosities up to 25 percent, substantiated by measurements obtained while taking fluid samples. These pressure measurements also confirm that the interval is over-pressured on trend with the 210/30a-4Y well, but some 900 psi lower than the discovery area. The implication of this information is that the southern fringe of the northern channel area is in communication with the central channel, being distinct from the main reservoir in the northern channel area. The well will be suspended for possible re-use as a future development well at this location or elsewhere after a sidetrack. With the completion of this four well drilling campaign, RPS Energy will start a review of the Cladhan resources with the intent of publishing an update report within a few weeks.

"Notwithstanding the presence of predominantly wet sands at this depth in this separate channel compartment, we are encouraged by the presence of oil in the top sand and by reservoir quality at this location. Further updip prospectivity is certainly promising," remarked John Rapach, Sterling's Chief Operating Officer. "We have proved that our current seismic model can adequately predict sand thickness but reservoir quality definition is now paramount for further appraisal and development drilling. Our next planned subsurface activity is to complete full reprocessing and interpretation of the existing seismic dataset incorporating all of the log, core, fluid and pressure results obtained during this current drilling campaign. Consequently, the next drilling campaign will probably commence in early 2012," noted Mr. Rapach.

"Our development planning is concentrating on either a subsea tie-back or FPSO development of the main northern core area with further definition of reserves and resources during our next drilling campaign. We are commencing pipeline route and environmental survey work within the next few weeks," added Mr. Rapach.

Mike Azancot, Sterling's Chief Executive Officer, commenting on these results noted, "The current exploration and appraisal drilling campaign on Cladhan has been successful in increasing the height of the oil column by 798 feet to 1228 feet in total. The extent of the development of the northern core area is now better defined with this increase in oil column. The fan area in the east of the field remains prospective as the results from the 210/30a-4Z well drilled in this campaign are not conclusive due to its proximity to a major fault. Our plan towards development with options for increased resource exploitation after further drilling is now underway with a target for first oil in 2014."

Sterling holds a 39.9% interest in license P1064 which contains Cladhan, and is the operator. The partners are Wintershall (UK North Sea) Ltd. with 33.5 percent, Encore Petroleum Ltd with 16.6 percent and Dyas UK Ltd with 10.0 percent.

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EnCore Reaches TD at Cladhan Appraisal Well

- EnCore Reaches TD at Cladhan Appraisal Well

Friday, June 03, 2011
EnCore Oil plc

EnCore announced that the Cladhan appraisal well 210/30a-4x, the final well in this current four well program located in UK North Sea Blocks 210/29a & 210/30a, has reached Total Measured Depth of 10,614 feet.

The appraisal well was drilled as a side-track to evaluate a channel to the south of the current Cladhan discovery. The well encountered an Upper Jurassic reservoir with a gross True Vertical Thickness (TVT) of 171 feet and 105 feet of net sand. Reservoir quality is excellent with porosities up to 25 per cent. Log and pressure data indicates that an uppermost sandstone unit of five feet TVT is hydrocarbon bearing with an "Oil Down To" at 10,177 feet True Vertical Depth Sub Sea (TVDSS) and a calculated Oil Water Contact at 10,200 feet TVDSS based on the pressure data. An oil sample was obtained from this interval. Below this oil bearing sand, a further 100 net feet of water-wet sands were encountered. Pressure data shows that the sands are over pressured in this well, and these are similar to the pressure trend encountered in the Central Channel drilled by the 210/30a-4y well, and therefore in a separate pressure regime from the main Cladhan accumulation. The presence of an Oil Down To indicates potential for a new accumulation, separate from Cladhan, up dip of the current well location and also potential up dip of the previously drilled 210/30a-4y well. The well will now be suspended for potential reuse in the development of the Cladhan area.

This final well completes the current phase of drilling at Cladhan and has helped delineate the discovery and provided greater clarity on what has been discovered in the Cladhan area, although there is still further appraisal work to be carried out in the area. An infield survey and pipeline survey is now planned to commence later this month to determine the best development options for the Cladhan discovery.

Commenting on the latest well result, Alan Booth, EnCore's Chief Executive Officer said, "Although the well results to date have been somewhat mixed, we have accomplished our main aim of identifying and delimiting the areal extent of the Cladhan field, or perhaps this should now be fields. A significant amount of work still lies ahead in integrating and calibrating the extensive well and core information into the seismic data, although initial analysis appears to suggest that the original Cladhan discovery is confined to the Northern Channel Belt immediately North of this current well. In the Northern Channel Belt, we have now established a hydrocarbon column of greater than 1,200 feet where reservoir quality, rather than an actual Oil Water Contact may well delimit producibility from the deeper, down dip 'fan area' of the discovery.

"The Central Channel area, drilled by the 210/30a-4y and the current 210/30a-4x wells, is in a separate pressure regime. This area is also over pressured, although not to the same degree as Cladhan. This latest well appears to have intersected the edge of an oil column and a potential Oil Water Contact some way down dip from the crest in a separate channel system. The sand quality in this location is excellent and suggests important potential further up dip in this channel. It gives us greater encouragement that the Central Channel (drilled by well 210/30a-4y) may well also contain oil trapped up dip, as this well was located some 1,000 feet below the mapped up dip limit of that particular channel.

"Further appraisal drilling, likely in the first half of 2012, will be required to understand the up dip potential in both these two new channel systems. In the mean time the Operator will continue with on going development planning.

"In terms of EnCore's upcoming work program, development studies and planning continue on our Catcher, Varadero and Burgman discoveries on the EnCore-operated UK Central North Sea Block 28/9. Further seismic data is to be acquired over the summer which will assist in this work and the Group hopes to be in a position to be able to return to Block 28/9 in late 2011 or early in 2012 to continue with further exploration and appraisal drilling.

"Our next well to be drilled will be on the EnCore-operated Tudor Rose discovery in UK Central North Sea Block 14/30a, which is expected to commence in September 2011. A Letter of Award has been signed with ADTI for use of the Sedco 704 rig to drill an appraisal well on the Tudor Rose accumulation to establish the gravity and viscosity of the oil in place, both critical issues in determining if Tudor Rose can be commercially exploited."

The equity in the Cladhan joint venture partnership is as follows: EnCore Oil plc (16.6 percent.), Sterling Resources Ltd (39.9 percent., Operator), Wintershall (UK North Sea) Limited (33.5 percent.) and Dyas (10 percent.).

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Sterling Reaches TD at Cladhan Appraisal

- Sterling Reaches TD at Cladhan Appraisal

Wednesday, May 18, 2011
EnCore Oil plc
by SubseaIQ

EnCore announced that the Cladhan appraisal well 210/30a-4y, the third well of a four well program located in UK North Sea Blocks 210/29a & 210/30a has reached Total Measured Depth of 12,615 feet.

The well was drilled as a side-track into the Central Channel prospect which lies to the south of the current Cladhan discovery. The well encountered two Upper Jurassic reservoir sand sequences with a gross true vertical thickness (TVT) of 191 feet and a net of 40 feet TVT. Log and pressure data indicates the sands are water wet. It would appear from the pressure data that the sands in the Central Channel area, although over pressured, are in a separate pressure regime from the main Cladhan accumulation.

The Group will now drill the final side-track of this drilling phase, approximately 150 feet up dip of the previous oil bearing 210/30a-4 well, with the objective of gaining further information on the southern sector of the Northern Channel area where the original Cladhan discoveries have been made. It is expected that this side-track will take approximately 15-20 days, subject to operational and weather requirements.

Commenting on the latest well result, Alan Booth, EnCore's Chief Executive Officer said, "This result has provided important information in outlining the extent of the overall Cladhan play within the license. Although the over pressured nature of the reservoir suggests there may be remaining prospectivity up dip from the current Central Channel well, this would likely need to be the subject of a future drilling campaign. This well and the previous 210/30a-4z deep well in the Fan area have not impacted on the established Cladhan discovery. However, the results start to limit the upside potential on the license as a whole, and suggest that the Cladhan field is likely confined to the Northern Channel belt area and an area up dip of the deep fan well.

"The Group intends to carry out an infield survey and a pipeline survey to determine the best development options for the Cladhan discovery."

The equity in the Cladhan joint venture partnership is as follows: EnCore Oil plc (16.6 percent.), Sterling Resources Ltd (39.9 perent., Operator), Wintershall (UK North Sea) Limited (33.5 per cent.) and Dyas (10 percent.).

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Sterling Drills First Side-track in Cladhan Campaign

Sterling Drills First Side-track in Cladhan Campaign

Thursday, May 05, 2011
Sterling Resources Ltd.

Sterling Resources Ltd. on Thursday announced the completion of drilling of the 210/30a-4Z well on Block 210/30a in the United Kingdom North Sea. This is the second well (first side-track) drilled in the current four well campaign to appraise further the extent of the Cladhan reservoir.

The 210/30a-4Z well was drilled at a location 1.6 kilometers east and a further 1240 feet downdip of the most recent 210/30a-4 well, utilizing the Transocean Prospect rig from a centrally positioned location. The objectives of the 210/30a-4Z sidetrack well were to appraise the field further east of previous well control and prove sand and oil presence in a fan system considerably deeper than previous wells which have been drilled into channel systems on a terrace structure.

The 210/30a-4Z well was drilled to a total measured depth (MD) of 15,900 feet having encountered two separate Upper Jurassic reservoir zones of 12 and 169 feet (vertical thickness) with oil shows through both intervals. No oil-water contact was encountered. Petrophysical analysis of the open-hole logs showed porosities up to 13.5% but with a high degree of dolomitic cement. Pressure measurements were attempted but not obtained.

"We have been able to prove-up a large depositional feature as prognosed from our seismic interpretation and with hydrocarbons quite deep in the structure," remarked John Rapach, Sterling's Chief Operating Officer. "Our challenge will be to understand the variation in reservoir quality in the eastern area of the field. We are only half way through our current campaign of drilling; the next well will target the central channel and the final well will be drilled to the southern portion of northern channel. These wells are planned into areas with similar seismic characteristics that have already encountered movable hydrocarbons. Success with these wells will build on our resource base inventory and provide further information for our ongoing development planning," added Mr. Rapach.

"While we would have preferred to see better quality sands in what appears to be a large package of oil filled reservoir, this is the first well into a deeper portion of the field and we have to remember that we are still exploring in an area with little well control," stated Mike Azancot, Sterling's President and CEO. "As is usually the case in the early phase of field appraisal, a number of wells are required to delineate the field. The partnership is planning reprocessing of current seismic data along with possible further seismic acquisition, which should improve understanding of reservoir quality variation. We still see much promise in this eastern fan area and we will be updating the geological model potentially to unlock significant prospectivity. Given that the first two wells of the current campaign have still not encountered an oil-water contact, the uncertainty of the prospective oil in place at least in the terrace area has been significantly reduced and should be further refined by the next two wells," added Mr. Azancot.

On completion of this appraisal campaign and following analysis of all data obtained, the partnership intends to commission an updated independent resource evaluation.

Sterling holds a 39.9% interest in license P1064 which contains Cladhan, and is the operator. The partners are Wintershall (UK North Sea) Ltd 33.5 percent, Encore Petroleum Ltd 16.6 percent and Dyas UK Ltd 10.0 percent.

Sterling Resources Ltd. is a Canadian-listed international oil and gas company headquartered in Calgary, Alberta with assets in the United Kingdom, Romania, France and the Netherlands.

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EnCore Repeats Success with Additional Cladhan Pay

EnCore Repeats Success with Additional Cladhan Pay

Tuesday, April 12, 2011
EnCore Oil plc

EnCore provided an update on the Cladhan appraisal well 210/30a-4 located in UK North Sea Block 210/30a.

The appraisal well was drilled as a deviated well to a Total Measured Depth of 12,252 feet and encountered oil bearing Upper Jurassic sandstones in two separate reservoir intervals. No Oil Water Contact was observed. The Upper reservoir sequence had a gross True Vertical Thickness (TVT) of 18 feet and a net sand of 13 feet TVT. The sand has an average porosity of 16 percent. and hydrocarbon saturation of 82 percent. Pressures suggest that this reservoir is in a separate pressure regime from the Lower reservoir. In the Lower reservoir sequence, the main reservoir in previous Cladhan wells, the well encountered a gross TVT of 256 feet and a net sand of 21 feet TVT. The sand has an average porosity of 16 percent. and hydrocarbon saturation of 75 percent. Initial pressure data indicates that the lower sand is in pressure communication with, and is part of the original Cladhan discovery. The well has proven an Oil Down To of 10,447 feet True Vertical Depth Sub Sea (TVDSS), giving a minimum hydrocarbon column of over 1,200 feet.

Upon completion of operations at well 210/30a-4, the Transocean Prospect semi-submersible rig will commence the first planned side-track, 210/30a-4z to evaluate the Upper Jurassic sandstones significantly down dip from the 210/30a-4 well in an attempt to define oil water contacts for both the upper and lower reservoir units, as well as investigating the potential for thickening of the upper unit. It is expected that this side-track will take approximately 20 - 25 days subject to weather or operational delays.

Commenting on the latest well result, Graham Doré, EnCore's Exploration Director said, "This is an important result for Cladhan. The well has confirmed both the presence of a large oil column in the main Cladhan reservoir as well as a new hydrocarbon bearing reservoir sequence, and has yet to find an Oil Water Contact. The next side-track to the east will evaluate the fan structure some 1,000 feet deeper, and has the potential to encounter improved net to gross as well as establishing Oil Water Contacts for both reservoir sequences. This will be followed by a side-track to the south which is designed to confirm the presence of oil in the Central channel."

The equity in the Cladhan joint venture partnership is as follows: EnCore Oil plc (16.6 percent.), Sterling Resources Ltd (39.9 percent., Operator), Wintershall (UK North Sea) Limited (33.5 percent.) and Dyas (10 percent.).

Graham Doré B.Sc. (Hons.) in Geology and M.Sc. in Petroleum Geology and EnCore's Exploration Director, who has over 25 years' experience in the oil exploration and production industry, has reviewed and approved the technical information contained in this announcement.