Final Relinquishment Report
Licence P1800
UKCS Blocks 22/17a and 22/22d
Idemitsu Petroleum UK Ltd.
April 2015
Compiled by:
CNS Team (CNS Team Leader: D. Waters)
Idemitsu Petroleum UK Ltd.
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Contents
1
LICENCE INFORMATION .........................................................................................................................3
2
LICENCE SYNOPSIS ................................................................................................................................3
3
WORK PROGRAMME SUMMARY ...........................................................................................................4
4
DATABASE ...............................................................................................................................................6
4.1
4.2
5
PROSPECTIVITY UPDATE .......................................................................................................................6
5.1
5.2
5.3
5.4
5.5
6
Well database ......................................................................................................................................6
Seismic database & Inversion products............................................................................................6
Eocene..................................................................................................................................................8
Upper Palaeocene ...............................................................................................................................8
Chalk & Lower Cretaceous. ..............................................................................................................10
Late Jurassic .....................................................................................................................................10
Palaeozoic ..........................................................................................................................................17
FURTHER TECHNICAL WORK UNDERTAKEN ....................................................................................17
6.1
Basin modelling .................................................................................................................................17
7
RESOURCE AND RISK SUMMARY .......................................................................................................17
8
CONCLUSIONS .......................................................................................................................................19
9
CLEARANCE...........................................................................................................................................20
10
ABBREVIATIONS USED.........................................................................................................................20
11
CONTACT DETAILS ...............................................................................................................................20
Table listing
Table 1: Licence synopsis ...................................................................................................................................... 3
Table 2: Seismic database .................................................................................................................................... 7
Table 3: Notional Syros Well details..................................................................................................................... 16
Table 4: Prospectivity summary .......................................................................................................................... 18
Table 5: Summary of risks for remaining prospects/leads .................................................................................. 19
Figure listing
Figure 1: Map of remaining licence prospectivity .................................................................................................. 4
Figure 2: Stratigraphic column and prospectivity, blocks 22/17 & 22/22 .............................................................. 5
Figure 3: Seismic and well database .................................................................................................................... 7
Figure 4: Comparison of the seismic surveys, PGS MSP & CGG Cornerstone/Broadseis .................................. 8
Figure 5: 22/16b-5 Logs ......................................................................................................................................... 9
Figure 6: "Hydrocarbon Stack" as a Cromarty oil indicator, on PGS MSP data ................................................... 9
Figure 7: dBGT attribute Near Top Sele, CGG on Cornerstone and BroadSeis data (CGG) .............................. 10
Figure 8: Jurassic well correlation interpod play ................................................................................................. 11
Figure 9: 22/17-4Z Fulmar & Ribble Petrophysics ............................................................................................... 11
Figure 10: PGS MegaSurvey Plus arbitrary line, key Fulmar Targets (PGS MSP) ............................................ 12
Figure 11: 22/17-4Z Godwin discovery well seismic tie, MS plus (PGS) ............................................................ 13
Figure 12: Syros-Godwin Smith Bank Pod morphology (TWT) ........................................................................... 13
Figure 13: Syros & Godwin Pressures and Top Fulmar Depth ............................................................................ 14
Figure 14: Fulmar interpod definitions from Fulmar amplitude (PGS MSP) and impedance (mainly CGG
Cornerstone)......................................................................................................................................................... 14
Figure 15: Syros Impedance dip section (Cornerstone data set basis - CGG) .................................................... 15
Figure 16: Godwin-Syros Impedance arbitrary line section (Cornerstone data set basis - CGG) ....................... 15
Figure 17: Dip section through "Shawsgate" Lead (Cornerstone – CGG) ........................................................... 16
Figure 18: R1 Rotliegend Prospect seismic section (Cornerstone – CGG) ........................................................ 17
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1 LICENCE INFORMATION
P1800 was awarded 100% to Idemitsu on January 10th 2011 as part of the UK 26th offshore licencing round. This
was a traditional licence award with a four year term, and consequently the licence expired on 10 th January 2015.
The blocks involved (as designated at the time of award) were 22/17a and 22/22d located on the eastern flank of
the Montrose-Arbroath High (MAH) where it adjoins the West Central Graben (WCG) in the Central North Sea
(CNS) – see Figure 1: Map of remaining licence prospectivity.
Where appropriate, permissions to publish have been obtained from the relevant vendors, including PGS and
CGG.
2 LICENCE SYNOPSIS
The main 26th Rd commitments made on the licence were
 a drill-or-drop to the shallower of the base Tertiary or 2900 m.
 to obtain 145 km2 of 3D (the area of both blocks combined).
The commitment was met with 145 km 2 of CGG Cornerstone 3D and Broadseis data.
Table 1: Licence synopsis
Early leads at Upper Palaeocene level consisted of amplitude and preliminary AVO analysis anomalies that were
coincident with pinch-outs and/or structural noses. At Jurassic level, amplitude responses signalled several
Upper Jurassic leads of an interpod and combined interpod/fault seal nature, and one small 4 way closure (see
Figure 1: Map of remaining licence prospectivity). Fulmar sands form the main reservoir objective at this
level, but prospectivity is also recognised for the Upper Jurassic Ribble and Freshney sands – particularly in more
basinal areas. Key prospective intervals are illustrated in Figure 2: Stratigraphic column and prospectivity,
blocks 22/17 & 22/22.
During Idemitsu’s tenure on the licence, additional CGG Cornerstone 3D and Broadseis data was purchased to
allow greater delineation of the Upper Jurassic. At the same time, highly relevant wells on the neighbouring
Jurassic interpod play discoveries were released, including Cayley, Godwin, and Shaw. Godwin in particular
significantly de-risked the Upper Jurassic interpod play on the licence, and two new prospects Syros and Sicily
were identified from the greater Upper Jurassic resolution on the acquired datasets. However, detailed rock
physics analysis of the newer datasets, downgraded the likelihood of an HC AVO response within the upper
Palaeocene leads.
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Figure 1: Map of remaining licence prospectivity
Idemitsu has retained 100% equity throughout its tenure on the licence. Idemitsu wished to drill the Syros
prospect and identified a suitable well location, but not at 100% exposure. Attempts to farm-down to 50% were
unsuccessful leading to eventual relinquishment. Idemitsu would be interested in discussions with interested
parties wishing to progress this now open acreage.
3 WORK PROGRAMME SUMMARY
Initial regional interpretation of the licence was carried out pre-award on the PGS MegaSurvey Plus PSTM data.
Preliminary attribute analysis work identified promising anomalies in the Upper Palaeocene, including potential
pinch-outs of the Cromarty sandstone, and smaller closures at Cromarty and Forties level. Preliminary depth
conversion and attribute analysis work also identified a number of leads at Jurassic level including the Syros and
Sicily Prospects.
Upon award, a full suite of geological studies were initiated. Full PVT and Sw data assembly utilised all offset
field data at Palaeocene and Jurassic levels. Core data analysis and petrophysical analysis of key wells was
undertaken. Biostratigraphic, sequence stratigraphic, and facies correlation work was initiated including nonproprietary and proprietary Ichron biostratigraphic studies. The key wells used at various stratigraphic levels are
shown in Figure 3: Seismic and well database.
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Figure 2: Stratigraphic column and prospectivity, blocks 22/17 & 22/22
The CGG 3D Cornerstone data, including four angle stacks, was delivered to Idemitsu in April 2012. This was
followed closely in May 2012 by release of the Cayley wells 22/17-3, 3X, 3Y, 3Z. The CGG Broadseis data was
delivered to Idemitsu in August 2012.
Relevant petrophysical, PVT, and rock physics analyses of the Jurassic interval in the Cayley wells were
undertaken, and these wells were integrated into new interpretation of the CGG Cornerstone data. Two depth
conversion models were applied using the CGG Cornerstone data to investigate sensitivity to depth conversion
method:
1. A three layer model formed the base case, with intervals: sea floor to BCU, BCU-KCF and KCF-Top
Fulmar.
2. Another five layer model also utilised sea-floor to Top Sele, Top Sele to Top Chalk, and Top Chalk to
BCU.
Prospect resources at were found to be relatively insensitive to depth conversion method. Meanwhile, spectral
decomposition work on the CGG Cornerstone dataset facilitated greater fairway delineation at the
Tay/Cromarty/Forties levels.
Armed with a new interpretation at deeper levels, an in-house basin modelling project was undertaken (see
Section 6.1), to assist phase prediction in the various leads and address concerns about a relative lack of lack of
fault migration pathways from basinal parts of the licence into Palaeocene objectives.
In early 2013, utilising the new CGG Cornerstone 3D and Broadseis data, a major rock physics project was
directed at the Palaeocene prospectivity, conducted in house by Idemitsu with support from PGS Reservoir. Pimpedance volumes, Vp/Vs volumes and derived “HC stack” volumes were generated, as well as AVO attribute
maps. These studies successfully extracted low Vp/Vs and high “HC stack” responses for known Forties
accumulations in the area, but a lack of response in the Cromarty sandstone leads on the licence downgraded
this prospectivity.
Work was therefore widened to review prospectivity in targets secondary to the upper Palaeocene and Upper
Jurassic, most notably within the Eocene Tay Formation, Chalk, and Palaeozoic prospectivity within Zechstein
carbonates and Rotliegend Auk Formation (see Figure 2: Stratigraphic column and prospectivity, blocks
22/17 & 22/22).
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As evaluation proceeded on the new CGG Cornerstone data, it became increasingly evident that attractive new
prospectivity (Sicily and Syros prospects) in the far eastern areas of the licence required critical calibration with
the nearby Godwin Discovery wells 22/17-4 & 4Z. An additional 95km 2 of CGG Cornerstone 3D was acquired off
the licence area to facilitate this calibration.
New petrophysical, PVT, and rock physics analyses were then undertaken on the Godwin wells, and the
synthetics & ties were integrated into interpretation of the extended CGG Cornerstone data set. A post-stack
inversion (maximum likelihood sparse spike) further confirmed prospectivity at Fulmar level – with the Syros
prospect being considerably enlarged and de-risked by the calibration with Godwin discovery. A preliminary well
location and prognosis was made (21/17b-E) for the Syros prospect and a farm-down process was initiated.
Further work on Rotliegend and Zechstein prospectivity matured to the R1 lead in late 2013 (see Figure 1: Map
of remaining licence prospectivity). New well data from the Shaw discovery was also released in January
2014, and petrophysical analysis on the relevant wells (22/22a-7, 7Z, 7Y) was completed.
A further look at chalk potential, including wells 22/22a-1, 22/22b-4Z, 22/23b-1, and the Banff and Machar fields
was also undertaken. Likewise the Eocene potential incorporating Gannet and Milburn analogues were reviewed.
No significant prospectivity was identified at these levels.
4 DATABASE
4.1 Well database
The key wells used to understand the various stratigraphic levels of the licence are shown in Figure 3: Seismic
and well database. It includes key well synthetics and well ties (IPUK), core data analysis (IPUK), petrophysical
analysis, (IPUK), rock physics studies (IPUK & PGS), pressure data (IHS, CDA), as well as biostratigraphic,
sequence stratigraphic, and correlation work (Ichron & IPUK).
4.2 Seismic database & Inversion products
The key seismic datasets obtained are shown in Figure 3: Seismic and well database and listed in Table 2:
Seismic database. The associated inversion products were also derived:
Inversion products derived from PGS MegaSurvey Plus PSTM
o In house preliminary inversion at Paleocene level (Idemitsu)
o Palaeocene P-impedance, Vp/Vs, HC stack volumes (IPUK exclusive study with PGS)
Inversion products derived from CGG Cornerstone and Broadseis
o Fulmar Post stack maximum likelihood sparse spike (in house)
The PGS MegaSurvey Plus (MSP), CGG Cornerstone, and CGG Broadseis data sets were all useful products
for analysis of the licence. A decision to obtain CGG Cornerstone and Broadseis was driven by a need to better
resolve Intra-Late Jurassic geometries and ties to the Godwin wells, but also had benefits at Paleocene level. A
comparison of the datasets is shown in Figure 4: Comparison of the seismic surveys, PGS MSP & CGG
Cornerstone/Broadseis.
5 PROSPECTIVITY UPDATE
A map of the leads and prospects envisaged at the time of relinquishment is given in Figure 1: Map of remaining
licence prospectivity. A summary of the associated volumes and risks and their evolution through time is given
in Table 4: Prospectivity summary. The volumes and risks listed are the latest Q4 2014 internal peer review
within Idemitsu, made as a precursor to the relinquishment decision. While some Upper Palaeocene leads are
retained for completeness, the lack of AVO response downgrades their perceived prospectivity significantly. The
main remaining prospectivity on block is at Upper Jurassic level within the Fulmar Formation interpod play.
Secondary prospectivity at Upper Jurassic turbidite levels (Ribble/Freshney) and Rotliegend levels remains, but
the risks are higher and volumes are smaller in these secondary targets.
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Table 2: Seismic database
Figure 3: Seismic and well database
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Figure 4: Comparison of the seismic surveys, PGS MSP & CGG Cornerstone/Broadseis
5.1 Eocene
A top Tay amplitude map, derived from the PGS MegaSurvey Plus PSTM data, was used to delineate the Tay
fairway, but no significant closures are evident in the licence area, and offset Tay sandstone discoveries all occur
within such closures. Detailed rock physics analysis of key offset wells including the Gannet D 22/21-D7 well,
22/23c-3Z, 22/22b-2, 22/22b-4,22/22b-5 and 22/22c-6, gave no clear encouragement for a Tay HC accumulation
on the licence, certainly within any closure, and on that basis Tay Sst prospectivity was not pursued further.
5.2 Upper Palaeocene
Initial rock physics work was undertaken using the PGS MegaSurvey Plus PSTM data. Rock physics modelling
of wells 22/16b-5 (see Figure 5: 22/16b-5 Logs) and 22/23b-1 was carried out to understand the AVO behaviour
of Cromarty sandstone. Fluid replacement modelling was applied to the two wells, and offset well data and nearby
field data were used to guide the fluid replacement parameters. Results suggested fluid effects should be evident
within both the Cromarty and Forties sandstones, but weaker within Forties sandstone. AVO modelling was
undertaken for both wells and suggested clear AVO responses should be evident in the oil case scenario,
particularly for 22/16b-5. Learnings from the rock physics modelling were then applied to the inversion volumes,
of P impedance, Vp/Vs and the “Hydrocarbon stack” attribute derived from these two parameters.
Confidence in the method was obtained by noting positive correlation between “Hydrocarbon Stack” values and
Forties oil accumulations at Arbroath, Montrose. Applying the same method to the Cromarty, (Figure 6:
"Hydrocarbon Stack" as a Cromarty oil indicator, on PGS MSP data) only the leads Viti and Vanua show
significant deviation from background trend, but even here there is no clear structural conformance, and it is
difficult to say unambiguously that this is not a reservoir quality effect. Moreover, the responses at Biddenden
are very subdued, with only slight deviation from background, and in the areas of Eglantine and Adgestone there
is no response evident, so those latter two leads were downgraded.
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Figure 5: 22/16b-5 Logs
Figure 6: "Hydrocarbon Stack" as a Cromarty oil indicator, on PGS MSP data
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Further rock physics modelling and AVO analysis was completed when the CGG Cornerstone and Broadseis
datasets were received. In terms of broad structural information the three datasets provide similar information,
but the Broadseis has higher resolution and more high frequency information. It was apparent from this analysis
that any AVO anomalies are even less prominent than for the PGS MegaSurvey Plus, including Viti and Vanua
Leads (Figure 7: dBGT attribute Near Top Sele, CGG on Cornerstone and BroadSeis). On this basis, the
Upper Palaeocene prospectivity on the licence was downgraded further, and focus shifted to the Late Jurassic.
Figure 7: dBGT attribute Near Top Sele, CGG on Cornerstone and BroadSeis data (CGG)
5.3 Chalk & Lower Cretaceous.
A low relief TWT structural nose with some small TWT “closure” exists at top chalk level on the licence (see
Figure 1: Map of remaining licence prospectivity). Any good reservoir within the chalk would be expected to
have some amplitude response but on the P1800 licence there is no such response to compare with anomalies
in the Banff, Kyle, Curlew C, Acorn, Joanne, and Stella areas where chalk does produce. Similarly offset wells
at 22/22a-1, 22/22b-4Z and 22/23b-1 give little cause for encouragement. Even if a chalk reservoir was present
within the closure, the low structural relief means that commercial saturations are unlikely to be present. In that
context, chalk prospectivity was not pursued further on the block. Similarly, there was insufficient encouragement
from offset wells to pursue any Lower Cretaceous mass flow sand prospectivity within this time closure or
elsewhere on the licence.
5.4 Late Jurassic
The main remaining prospectivity on the licence is late Jurassic in age, and predominantly at Fulmar level. There
are other non-Fulmar sands present in the area, which we refer to loosely as “Ribble sandstone” units. These
are a series of thin sands present in the J54 to J64 interval within the licence area, mainly in the deeper more
basinal parts of the West Central Graben. This includes wells 22/1-8, 22/22b-4, 22/22b-2, 22/23b-6, 22/23b-5.
They are however thin when present, and on the intermediate “slope” areas between the Montrose-Arbroath high
and the basin axis, a more restricted distribution or sediment bypass seems likely. Equivalent aged sandy
sections are however present in more proximal locations to the Montrose Arbroath high also, such as in the Cayley
and Godwin area (see wells 22/17-3 & 3X, 22/17-4, Figure 8: Jurassic well correlation interpod play) where
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they can have minor HC saturations. The reservoir quality is however significantly reduced relative to the Fulmar
(Figure 9: 22/17-4Z Fulmar & Ribble Petrophysics). For this reason the Ribble sands have been treated as an
interesting secondary target, but unlikely to form an objective worth pursuing in their own right, at least within the
licence area.
Figure 8: Jurassic well correlation interpod play
Figure 9: 22/17-4Z Fulmar & Ribble Petrophysics
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The Late Jurassic interval has been mapped sub-regionally on the PGS MegaSurvey Plus PSTM and where
feasible included picking of the BCU, Top Triassic/Skagerrak, Top Smith Bank, Top Zechstein, and Top
Rotliegend. Figure 10: PGS MegaSurvey Plus arbitrary line, key Fulmar Targets shows the section of an
arbitrary line between the main Jurassic prospect on the licence and nearby Fulmar analogue accumulations at
Cayley, Godwin, Shaw and Wood. A fairly typical interpod character is evident. More detailed mapping has been
undertaken on the more recent CGG Cornerstone and Broadseis data sets, including detailed well ties. The
closest and most important well ties are with the Godwin wells 22/17-4 and 22/17-4Z (Figure 11: 22/17-4Z
Godwin discovery well seismic tie) but critical well ties were also made at Jurassic levels with 22/17-3 & 3X
(Cayley) & 22/22a-7Z (Shaw).
The Top Smith Bank TWT map (variably the base Fulmar, Pentland and Skagerrak in the area) is shown in Figure
12: Syros-Godwin Smith Bank Pod morphology (TWT). A key feature is the extension of sealing ridges of
Smith Bank “pods” extending out from the main Montrose Arbroath High. These appear to play a controlling role
in the spill points of Shaw and Godwin, and a similar sealing mechanism is therefore invoked for Syros. The most
critical feature is the Smith Bank “arm” extending between Syros and Godwin. Two depth conversion models
were applied to the Late Jurassic, but there was little apparent GRV sensitivity to the model used. The base case
uses a three layer model: i) MSL to BCU, ii) BCU to Top Fulmar, and iii) below Top Fulmar. The resulting Top
Fulmar depth map is illustrated in Figure 13: Syros & Godwin Pressures and Top Fulmar Depth, with high
and low case lowest closing contours (LCC). Pressure data and the inferred OWC for Godwin discovery are also
shown. These appear to confirm that the Godwin contact must be controlled by a Smith Bank Pod “arm” similar
to the trap concept invoked for Syros.
Figure 10: PGS MegaSurvey Plus arbitrary line, key Fulmar Targets (PGS MSP)
Encouragements for Fulmar reservoir presence were first received on the PGS MegaSurvey Plus amplitudes,
and further inversion work on CGG Cornerstone seismic suggested well defined Fulmar reservoir “interpods”
pinching out and laterally sealed between Godwin, Syros, Sicily, and Shaw (see Figure 14: Fulmar interpod
definitions from Fulmar amplitude (PGS MSP) and impedance). The fault seal dependent Shawsgate lead
is also apparent on these maps. Rock physics work based on the Godwin wells suggest that a threshold P
impedance of < 9000 m/s*g/cc is a useful discriminator of Fulmar reservoir, but that it is difficult to distinguish
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brine and HC fill. A P-impedance dip section (see Figure 15: Syros Impedance dip section) and an arbitrary
line P-impedance section (Figure 16: Godwin-Syros Impedance arbitrary line section) illustrate the pinchout
and separation by Smith Bank Pods of the Syros Prospect from Sicily lead and Godwin.
Figure 11: 22/17-4Z Godwin discovery well seismic tie, MS plus (PGS)
Figure 12: Syros-Godwin Smith Bank Pod morphology (TWT)
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Figure 13: Syros & Godwin Pressures and Top Fulmar Depth
Figure 14: Fulmar interpod definitions from Fulmar amplitude (PGS MSP) and impedance (mainly CGG
Cornerstone)
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Figure 15: Syros Impedance dip section (Cornerstone data set basis - CGG)
Figure 16: Godwin-Syros Impedance arbitrary line section (Cornerstone data set basis - CGG)
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On the basis of the various work programme
analyses, Syros and Sicily have been risked
similarly at 35%, with containment the
critical risk (see Table 5: Summary of
risks for remaining prospects/leads).
Volumetric input parameters were taken
from regional offset well data for the Fulmar,
and Godwin and Cayley in particular. The
Pmean recoverable oil volume for Syros is
19.2 mmbbl and for Sicily is 14.4 mmbbl
(see Table 4: Prospectivity summary),
but the shared risks mean a high amount of
dependency between them – Sicily has a
very
good
chance
of success if Syros works. P10 oil
Table 3: Notional Syros Well details
volumes for Syros and Sicily are 32.2 and 25.1 mmbbl
respectively making them an attractive combined target.
After internal review, Syros was still considered an attractive target and approval to proceed was achieved,
contingent on successful farm-down to share the risk. A notional well location, just off the P90 volume contour,
was selected and scoping parameters for the notional well location are listed in Table 3: Notional Syros Well
details.
Sicily Prospect is essentially a very similar and smaller along strike equivalent of Syros. Shawsgate is an
additional Fulmar lead, as shown in Figure 17: Dip section through "Shawsgate" Lead. It is more sizeable
than Sicily (mean ~ 23 mmbbl), but has an element of fault seal required, and is therefore much riskier (Pg 15%).
Other small structures at Fulmar level were identified in early evaluations of the licence, but are either too small
or too risky for consideration in a commercial context. These structures are summarised in Table 4:
Prospectivity summary and Table 5: Summary of risks for remaining prospects/leads.
Figure 17: Dip section through "Shawsgate" Lead (Cornerstone – CGG)
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5.5 Palaeozoic
Charge into Palaeozoic reservoirs of the Zechstein and Rotliegend units is demonstrated by the small Carnoustie
oil accumulation underneath Arbroath field, which produced from Zechstein limestone from 1994 until late 2013
(see Figure 1: Map of remaining licence prospectivity). The neighbouring 22/18-1 well also demonstrates
the presence of good Rotliegend reservoirs (see Figure 3: Seismic and well database).
Figure 18: R1 Rotliegend Prospect seismic section (Cornerstone – CGG)
A tilted fault block at Rotliegend level with sufficient fault offset to allow juxtaposition against Late Jurassic source
rocks (KCF and/or Heather Fm.) is recognised on the licence, and assigned the name “R1”. The crestal depth is
~ 4225 m TVDSS with a spill around 4375 m TVDSS, into another small fault block. If that also seals, spill could
be up to 100 m deeper. A seismic section is shown in Figure 18: R1 Rotliegend Prospect seismic section.
The resources and risks associated with both the Rotliegend prospects, and a possible Zechstein secondary
reservoir similar to Carnoustie, are listed in Table 4: Prospectivity summary and Table 5: Summary of risks
for remaining prospects/leads
6 FURTHER TECHNICAL WORK UNDERTAKEN
6.1 Basin modelling
Given the wealth of discoveries in the area, hydrocarbon charge was not perceived as a key risk. An effort was
however made to understand the likelihood of an oil versus a gas accumulation at Syros, and the other P1800
prospects. To this end 2D basin modelling was undertaken. Results suggested a predominance of oil generation
over gas, with an onset of oil generation around 55Ma, and a peak in deeper parts of the kitchen area at around
30 Ma (later ~ 20 Ma in shallower kitchen areas). 2D modelling also illustrated a lack of connectivity between the
main gas kitchen and the P1800 Jurassic prospects – suggesting any remaining gas accumulations are likely to
be limited to the deeper graben flanks, and that in the P1800 area oil accumulations should predominate.
7 RESOURCE AND RISK SUMMARY
Figure 1: Map of remaining licence prospectivity illustrates Idemitsu’s view of the key remaining prospects
and leads on the licence. Table 4: Prospectivity summary lists the associated volumes, and Table 5:
Summary of risks for remaining prospects/leads lists the associated risks.
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Table 4: Prospectivity summary
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It remains Idemitsu’s view that Syros Fulmar prospect, with a P50 recoverable volume of ~ 17 mmbbl and ~7bcf,
and a P10 recoverable volume of ~32 mmbbl and ~16 bcf, remains the most attractive prospect on the block,
assigned a chance of geological success of 35%. The mean resource is ~ 19 mmbbl and ~ 10 bcf, i.e. ~ 21
mmboe. Furthermore, there is a strong positive dependency in a success case at Syros for additional resource
at Sicily prospect. This represents a further ~12mmbbl in the P50 case and ~25 mmbbl for the P10 (~14 mmbbl
for the mean).
Prospectivity remains at Rotliegend and Zechstein level (R1), but the Zechstein would be very small (3 mmboe
at P50 level). For the Rotliegend it is better, at ~ 11 mmboe, and it looks more favourable at P10 level (~39
mmboe). We assign R1 a chance of geological success of 20%, but in commercial terms any attempt to exploit
it would be difficult to justify without a short tie back to an existing accumulation.
Table 5: Summary of risks for remaining prospects/leads
8 CONCLUSIONS
A detailed work programme undertaken by Idemitsu on the P1800 licence has fulfilled all commitments made
during the 26th Round application. Evaluation of all prospective stratigraphic levels on the licence leaves
remaining prospectivity at Paleocene, Jurassic, and Permian levels. The rock physics work undertaken has
however downgraded the Paleocene prospectivity such that it now has either very small or very high risk
prospects. The work did not support HC fluid accumulations in the larger Cromarty pinch-out prospects. Similarly,
there remains prospectivity within a small to moderate sized fault block (R1) at Rotliegend sandstone and
Zechstein carbonate level, but without other accumulations on the licence, the commerciality looks weak.
The work programme has however been encouraging for the Syros prospect and its smaller lookalike, the Sicily
prospect, at Fulmar level within the Late Jurassic. Both are similar in nature and assigned a Pg of 35%. Syros
has a mean resource of just under 21 mmboe (19.2 mmbbl, 9.6 bcf), and if successful it is difficult to imagine
Sicily prospect, with a further 14 mmbbl, not also being successful. Together they give a combined mean
recoverable resource of ~ 35 mmboe. Attempts to farm-down within the licence time frame were however
unsuccessful, leading to eventual relinquishment.
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9 CLEARANCE
Permissions for the publication of seismic data have been sought and granted, with our thanks, from PGS for
their MegaSurvey Plus data, and from CGG for their Cornerstone and Broadband data.
10 ABBREVIATIONS USED
AVO: Amplitude versus Offset
BCU: Base Cretaceous Unconformity
CNS: Central North Sea
dBGT: deviation from Background Trend
Fm: Formation
IPUK: Idemitsu Petroleum UK
KCF: Kimmeridge Clay Formation
LCC: Lowest closing contour
MAH: Montrose Arbroath High
MS: PGS MegaSurvey
MSP: PGS MegaSurvey Plus
MSL: Mean sea level
Pg: Chance of geological success
UKCS: UK continental shelf
WCG: West Central Graben
11 CONTACT DETAILS
Parties interested in future co-operation in the area can contact Idemitsu directly:
6th Floor Shaftesbury House
151 Shaftesbury Avenue
London
WC2H 8AL
Tel – Switchboard +44 (0) 20 7395 6140
CNS Team Leader:
email – [email protected]
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