Ardent Oil Limited. Relinquishment report. Promote Licence P1953. Blocks 22/24h. March 2015

Transcription

1 Ardent Oil Limited Relinquishment report Promote Licence P1953 Blocks 22/24h March 2015 Licence P1953 Block 22/24h Relinq report Page 1 of 9 Ardent Oil Limited

2 Relinquishment report for Block 22/24h 1.0 Licence Information Licence Number: P1953 Licence Round: 27 th Licence Type: Promote Block number(s): 22/24h Group Partners: Ardent Oil Limited 33% (Administrator), Strike Oil Limited 33%, Frequent Oil Limited 34% Permission: All third party ownership rights on any data and/or interpretations presented in this report have been considered and cleared for publication purposes. DECC is therefore free to publish the report. Marnock/ Skua Figure 1: Location Map for Block 22/24h to be relinquished Licence P1953 Block 22/24h Relinq report Page 2 of 9 Ardent Oil Limited

3 2.0 Licence Synopsis Promote Licence P1953 is a 27 th Round award commencing on 1 st January 2013 and has completed its second year of the initial two-year Promote period. The work commitment for this period, which has been completed, was as follows: PART I (initial promote period of 2 years) (a) (b) Reprocess 28 km² of 3D seismic data; Use ADF Technology to identify anomalies. Should the group wish to retain the Licence beyond this period, it must commit to the following: PART II (2 further years) (a) (b) Drill or drop one well 3300m or 100m into the Top Chalk, whichever is the shallower; or: Elect to allow the licence to automatically cease Following completion of the 3D reprocessing through the ADF technique several prospects were identified but subsequent efforts to promote them proved unsuccessful - probably due to their limited size. Therefore the group partners decided to relinquish the Licence in its entirety and this Relinquishment report forms part of the surrender documentation required by DECC. Original play concept The 27 th Round Application was made on the basis of utilising a proprietary processing technique, ADF, which would be used to screen for any undrilled anomalies on the PGS MegaSurveyPlus MC3D data on this block. Any new anomalies may be indicative of the presence of missed hydrocarbons using the frequency based proprietary ADF 3D reprocessing technique patented by Apex Spectral Inc. of Houston, USA. Part of a larger area applied for the awarded block contained a prognosed Jurassic filled half graben (figure 2) with the possibility of stratigraphic trapping which would be investigated utilising the ADF processed data. Licence P1953 Block 22/24h Relinq report Page 3 of 9 Ardent Oil Limited

4 There were no other leads or prospects identified within the block. Figure 2: Application mapping and interpretation 3.0 Work Programme Summary The Licence is in its initial 2-year promote period and the following work programme has been completed: PART I (a) (b) Reprocess 28 km² of 3D seismic data - COMPLETED Use ADF Technology to identify anomalies - COMPLETED Results of ADF reprocessing: ADF (Alpha Dominant Frequency) processing was performed on the 3D seismic volume within the block. The final product is an ADF cube where the highest values indicate areas where a lowering of the dominant frequency and a steepening of the slope (Alpha) of the spectrum of the travelling wavelet occurs. This behaviour can be shown to be the result of a Licence P1953 Block 22/24h Relinq report Page 4 of 9 Ardent Oil Limited

5 change in fluid mobility present in a reservoir indicating oil or gas fill, although large changes in permeability (eg fractures) can also give similar results. Any anomaly must therefore be screened to determine whether it is likely to be the result of hydrocarbons or some other geological factor. Both cross sections and amplitude extractions relative to interpreted horizons within the block were used to scan the ADF volume for anomalies. The results of this screening are reviewed in the prospectivity update (section 5). 4.0 Database 4.1 Seismic database Figure 3: Seismic and well database Licence P1953 Block 22/24h Relinq report Page 5 of 9 Ardent Oil Limited

6 Ardent Oil licensed the PGS MegasurveyPlus MC3D data which covers Block 22/24h and the immediate environs in their entirety. The ADF processing was restricted to the licensed area. 4.2 Well database Sufficient wells were purchased and reviewed to support the geological and geophysical interpretation of the licence. 5.0 Prospectivity Update Prior to award no prospective areas were identified other than the possible Jurassic half graben in the north eastern corner of block 22/24h. Figure 4: TWT Structure Top Sele and Top Triassic Post award mapping confirmed the lack of significant structural closure (figure 4) and a quick look AVO performed using the offset PGS MegasurveyPlus MC3D data did not reveal any significant DHIs in the Forties Formation. Licence P1953 Block 22/24h Relinq report Page 6 of 9 Ardent Oil Limited

7 Figure 5: The evaluation of block 22/24h using the ADF data therefore concentrated on the possible Jurassic half graben in the north east corner of the block. Figure 5 illustrates the thick between Base Cretaceous Unconformity and Top Triassic where the possibility of Jurassic stratigraphic traps was recognised. Figure 6: Licence P1953 Block 22/24h Relinq report Page 7 of 9 Ardent Oil Limited

8 Figure 7: ADF Amplitude Extraction and Cross Section This evaluation revealed a small area of anomalous ADF values but with a cut-off down dip lacking conformance to depth, small overall area and a depth in excess of 4,000 metres it was not possible to derisk this lead to the extent necessary to mature it to prospect/drillable status. 6.0 Further technical work No further technical work was undertaken. 7.0 Resource and Risk Summary No prospects were identified. 8.0 Conclusions Following completion of the 3D reprocessing through the ADF technique and subsequent remapping a number of prospects were identified but Licence P1953 Block 22/24h Relinq report Page 8 of 9 Ardent Oil Limited

9 subsequent efforts to promote these to the industry proved unsuccessful mainly due to their limited size compared to the perceived commerce al threshold for this area. Therefore Ardent Oil plus all group partners decided to relinquish the Licence in its entirety, effective from 1 st January Clearance All third party ownership rights on any data and/or interpretations presented in this report have been considered and cleared for publication purposes. DECC is therefore free to publish the report. The 3D data examples shown herein are by courtesy of PGS and Apex Spectral Inc. Licence P1953 Block 22/24h Relinq report Page 9 of 9 Ardent Oil Limited