The licence contains the Tertiary Curlew-A oil accumulation discovered by well 29/7-1 (Shell, 1979). The discovery well found light oil in Tertiary Odin and Cromarty Sandstones (net 10.5 metres oil sands) within a salt-cored anticline. The anticline covers an area of approximately 21 square kilometres.
Corallian plans to drill an appraisal well in Q4 2019 to a depth of approximately 2,700 metres sub-sea in a water depth of approximately 90 metres.
A Competent Person’s Report (CPR) on Curlew-A was completed by Software Information Solutions, Schlumberger Oilfield UK (SLB) in February 2019. 2C Contingent Resources are estimated at 39 million barrels of oil equivalent (gross).
A secondary objective of the appraisal well is the Forties Sandstone which was not encountered in the discovery well but may be developed on the southwestern flank of the structure being targeted by the appraisal well.
Most Likely Prospective Resources of 22 million barrels of oil (gross) have been calculated for the Forties objective and a further 8 million barrels of oil (gross) in fractured Chalk within the crest of the structure (Corallian estimates).
Corallian holds a 90% interest in the licence and is Exploration Operator.
The well 98/11a-6 was drilled in February/March 2019 as a vertical well and reached a Total Depth of 1870m MD in the Sherwood Sandstone. The well was drilled to appraise the 98/11-3 well, drilled in 1986 by British Gas, within the Colter Prospect. The 98/11a-6 well unexpectedly remained on the southern side of the Colter Prospect bounding fault but encountered oil and gas shows over a 9.4m interval at the top of the Sherwood Sandstone reservoir. A petrophysical evaluation of the LWD data has calculated a net pay of 3m. Similar indications of oil and gas were encountered in the 98/11-1 well, drilled in 1983 by British Gas, within the Colter South fault terrace. Provisional analysis of the new data indicates that the two wells may a share a common oil-water-contact having both intersected the down-dip margin of the Colter South prospect. Corallian’s most recent assessment of the Colter South Prospect prior to drilling the 98/11a-6 well had estimated a mean recoverable volume of 15 mmbbls. Further work will be required to refine this assessment with the new well data.
A decision was made by the Joint Venture to drill a side-track (98/11a-6Z) to the north to evaluate the Colter Prospect. The well was drilled to a Total Depth of 1910m MD and encountered the Sherwood Sandstone below the oil-water-contact of the 98/11-3 well. Initial evaluation of the data from both wells indicates that the Colter Prospect is smaller than pre-drill estimates. The Colter South discovery remains an opportunity to evaluate further as it is now areally more extensive than indicated by the pre-drilling mapping. In addition, the side-track encountered oil and gas shows in the Jurassic Cornbrash-Lower Oxfordian interval, the producing reservoirs in the Kimmeridge oilfield, and this provides an interesting potential target on trend to the west within the onshore licences held by the Joint Venture. The data from these well results and existing data will be incorporated to determine the best forward plan.
Corallian holds a 49% interest in the licence and is Exploration Operator.
The P2398 licence is located on the southern flank of the Jawdaw field.
Corallian holds a 100% interest in the licence.
The 11/24b-4 exploration well was completed in January 2019. The well was drilled to a total depth of 1,000m. The objective of the well, the Beatrice Sandstone, was encountered at a depth of 933.5m but was water bearing.
Provisional petrophysical analyses indicated that the Beatrice Sandstone has a gross thickness of 22.8m with 19.8m of net sandstone of 17.2% average porosity. The remaining prospectivity in the licence is under review.
Corallian holds a 40% interest in the licence and is Exploration Operator.
These licences contain the Purbeck Prospect, an anticline which was drilled by the Southard Quarry-1 well in 1989, logging 8 metres hydrocarbon column in the Jurassic Bridport Sandstone. New seismic data was acquired over the prospect in 2016. Corallian holds a 49% interest in the licences and is Exploration Operator.