Licence P1958 Blocks 30/3c Relinq report Page 1 of 8 Ardent Oil Limited

Ardent Oil Limited

Relinquishment report

Promote Licence P1958

Block 30/3c

March 2015

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Relinquishment report for Block 30/3c

1.0 Licence Information Licence Number: P1958

Licence Round: 27th

Licence Type: Promote

Block number(s): 30/3c

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.

Figure 1: Location Map for Block 30/3c to be relinquished

Pierce

Blane

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2.0 Licence Synopsis

Promote Licence P1958 is a 27th Round award commencing on 1st 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) Reprocess 15 km² of 3D seismic data;

(b) 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) Drill or drop one well 3525m or 100m into the Top Chalk, whichever

is the shallower; or:

(b) 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 27th 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 an application for several blocks no specific prospects had been

identified within block 30/03c prior to award. Potential stratigraphic traps

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within the Lower Cretaceous and Kimmeridge Clay were anticipated in the

general area.

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) Reprocess 15 km² of 3D seismic data - COMPLETED

(b) Use ADF® Technology to identify anomalies - COMPLETED

Results of ADF® reprocessing:

ADF® (Alpha Dominant Frequency) processing was performed on the 3D

seismic volume within these blocks. 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

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 blocks 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

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Ardent Oil licensed the PGS MegasurveyPlus MC3D data which covers Block

30/3c and the immediate environs in their entirety. The ADF® processing

was restricted to the licensed area within UK waters.

Figure 3: Seismic and well database

4.2 Well database

Sufficient wells were purchased and reviewed to support the geological and

geophysical interpretation of the licence.

5.0 Prospectivity Update

No specific prospects had been identified in block 30/03c at the time of

application and mapping at Base Cretaceous Unconformity demonstrates

that this block is located in a low at BCU level (figure 4).

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Figure 4: BCU mapping and Migrated Seismic Data

The ADF® data was therefore used to scan the BCU to Triassic interval for

anomalies associated with potential stratigraphic traps (figure 5).

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Figure 5: ADF® Amplitude Extractions and Cross Section

The ADF® cross section and amplitude extraction show that any anomalies

within the Lower Cretaceous and Jurassic are generally weak and

discontinuous. Although there is a stronger and more extensive anomaly

seen just above the Base Chalk horizon no reservoir nor trapping mechanism

can reasonably be predicted for that section.

With the Paleocene Forties Blane Field to the south the very far offset data

was also reviewed for anomalies (figure 6).

Figure 6:

Although fairly weak there is an area of raised amplitude just below the Top

Sele horizon, corresponding to the Forties, within structural closure at Blane.

However in block 30/03c there are no significant closures mapped at Top

Sele or areas of raised amplitudes on the very far offset data.

6.0 Further technical work

No further technical work was undertaken.

7.0 Resource and Risk Summary

No prospects were identified.

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8.0 Conclusions

Following completion of the 3D reprocessing through the ADF® technique

and subsequent remapping a number of prospects were identified but

subsequent efforts to promote these to the industry proved unsuccessful –

mainly due to their limited size compared to the perceived commercial

threshold for this area. Therefore Ardent Oil plus all group partners decided

to relinquish the Licence in its entirety, effective from 1st January 2015.

9.0 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.