Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
Relinquishment Report
1. Header
License: P.039
Round: First
License Type: Traditional
Block: 49/21
Operator: ConocoPhillips
Partners in retained acreage
Block / Subarea Operator Equity Holder Interest 49/21a AREA A - INCLUDING VULCAN FIELD AREA
CONOCOPHILLIPS (U.K.) LIMITED ARCO BRITISH LIMITED 12.5
BP EXPLORATION (ALPHA) LIMITED 37.5
CONOCOPHILLIPS DEVELOPMENTS LIMITED 12.5
CONOCOPHILLIPS (U.K.) ALPHA LIMITED 12.5
CONOCOPHILLIPS (U.K.) LIMITED 25
49/21a VULCAN EAST SILVERSTONE SNS LIMITED ARCO BRITISH LIMITED 7.88
BP EXPLORATION (ALPHA) LIMITED 17.13
SILVERSTONE CNS LIMITED 25
SILVERSTONE SNS LIMITED 50
49/21b AREA A - VIPER AREA
CONOCOPHILLIPS (U.K.) LIMITED ARCO BRITISH LIMITED 12.5
BP EXPLORATION (ALPHA) LIMITED 12.5
CONOCOPHILLIPS DEVELOPMENTS LIMITED 12.5
CONOCOPHILLIPS (U.K.) ALPHA LIMITED 12.5
EOG RESOURCES UNITED KINGDOM LIMITED 50
49/21b AREA B - INCLUDING SOUTH VALIANT FIELD
CONOCOPHILLIPS (U.K.) LIMITED ARCO BRITISH LIMITED 12.5
BP EXPLORATION BETA LIMITED 37.5
CONOCOPHILLIPS DEVELOPMENTS LIMITED 12.5
CONOCOPHILLIPS PETROLEUM LIMITED 25
CONOCOPHILLIPS (U.K.) ALPHA LIMITED 12.5
Partners in retained acreage (cont.)
Block / Subarea Operator Equity Holder Interest 49/21b AREA B - VIPER AREA
CONOCOPHILLIPS (U.K.) LIMITED ARCO BRITISH LIMITED 12.5
BP EXPLORATION BETA LIMITED 12.5
CONOCOPHILLIPS DEVELOPMENTS LIMITED 12.5
CONOCOPHILLIPS (U.K.) ALPHA LIMITED 12.5
EOG RESOURCES UNITED KINGDOM LIMITED 50
49/21b AREA C - VIPER AREA
CONOCOPHILLIPS (U.K.) LIMITED ARCO BRITISH LIMITED 7.88
BRITOIL PUBLIC LIMITED COMPANY 17.13
CONOCOPHILLIPS DEVELOPMENTS LIMITED 7.88
CONOCOPHILLIPS LIMITED 9.25
CONOCOPHILLIPS (U.K.) ALPHA LIMITED 7.88
EOG RESOURCES UNITED KINGDOM LIMITED 50
49/21b AREA D - WEST EXCL. VULCAN & S. VALIANT
CONOCOPHILLIPS (U.K.) LIMITED ARCO BRITISH LIMITED 12.5
BP EXPLORATION BETA LIMITED 37.5
CONOCOPHILLIPS DEVELOPMENTS LIMITED 12.5
CONOCOPHILLIPS (U.K.) ALPHA LIMITED 12.5
CONOCOPHILLIPS (U.K.) LIMITED 25
Work Programme Summary:
1st Round License awarded 17
th September 1964
Work Obligation: Seismic acquisition plus 6 wells
10 Exploration wells have been drilled to date resulting in 4 significant discoveries; Vulcan and
South Valiant, which came on-stream in 1998, Vulcan C which came on-stream in 2004 and
more recently Vulcan East drilled by Silverstone Energy Ltd in 2007. Of the other 6 other
exploratory wells, 2 were drilled to appraise S. Valiant and one (49/21-3) was a dry hole whilst
the other 3 encountered gas shows and were deemed to be non commercial.
2. Synopsis
License Status: Block part relinquished in 2009 as part of DECC’s 1st Round License Extensions
initiative
3. Exploration Activities
Seismic:
Block 49/21 was originally covered by 2D seismic acquired in 1972 by SSL and reprocessed by
Horizon Exploration in 1984. A subsequent 2D survey infilling the original was acquired in
1983 by SSL.
The most recent data available is a full 3D Ocean Bottom Cable survey performed in 1996
which was originally processed by Western Geophysical. It was time processed in 1997 and
underwent pre-stack depth migration in 2000. The seismic data is currently owned by PGL.
Wells drilled in relinquished area:
49/21-1: drilled by Signal in 1966, gas shows with H2S, open hole DST, no gas to surface. P&A.
49/21-3: drilled by Conoco North Sea Ltd in 1972, gas shows, open hole DSTs, no gas to
surface. P&A.
49/21-8A: drilled by Conoco North Sea Ltd in 2001, approx. 220ft tight gas bearing reservoir,
no valid RFTs due to supercharging, not tested, P&A.
49/21-9z: drilled by EOG Resources in 2004, no gas shows, logs indicate approx. 40ft tight gas
bearing reservoir, No RFT s, not tested. P&A
4. Prospectivity Analysis:
Reservoir:
The Rotliegendes reservoir in this Block is subdivided into 4 primary zones.
Zone Geology Rock Properties Avg. Thickness
A Fine grained aeolian
dune and sheet sands,
reworked interval at top
(Weissliegend)
8-10% porosity
typically <1mD air
permeability
120’ TVT
B Fine to occasionally
med. grained mixed
sand sheet / aeolian
dune and interdune
10-15% porosity
typically 1-15 mD air
permeability
115’ TVT
C Medium to coarse
grained aeolian dune
sequence – dry Erg
equivalent
10-18% porosity,
typically 10 – 1000mD
air permeability
275’ TVT
D Mixed Aeolian / Fluvial 10-15% porosity
typically 1-15 mD air
permeability
205’ TVT
Source: The primary source rock for the Rotliegendes Fields is the prolific Carboniferous Coal
Measures
Seal:
The overlying Zechstein salts and anhydrites provide top and side seal across the area
Trap Type:
The primary trap type throughout this area is either 4 way dip closure or 3 way with fault
closure
Horizons of interest:
The horizon of interest in this Block is comprised of aeolian sandstones of the Rotliegendes
Group. Reservoir quality is seen to be a function of lithotype, depth of burial and the limited
degree of diagenesis that the reservoir has undergone. The upper most Zones, A&B, are
generally of much poorer reservoir quality in terms of in-situ permeability compared to Zone C,
to such an extent that the latter has been the primary target for prospect evaluation. Zone C is the
most significant producing unit in the Vulcan and South Valiant Fields.
Remaining prospectivity:
10 Exploration wells have been drilled on the Block resulting in 4 commercial discoveries.
However the relinquished area of this Block includes the 4 non commercial wells mentioned
previously. Prospect evaluation has to date focused on there being sufficient structural closure in
order to develop the high deliverability Zone C within the gas column. Consequently structures
with columns greater than 300ft have been required in order to ensure Zones A & B are well
above the gas water contact. It is believed that from the recent reviews by ConocoPhillips,
together with a number of farminees, including EOG and Silverstone Energy there is no
prospectivity of the type just described, remaining in this area.
The enclosed Top Rotliegendes time structure map does show a remaining low relief closure in
the south east of the Block, but due to this lack of relief, it would only have Zone A and B
developed within closure and consequently would be a tight gas opportunity, requiring as a
minimum, additional stimulation in order to secure commercial gas rates.
5. Reserves Summary:
It is ConocoPhillips’ opinion that all commercially prospective accumulations have now been
drilled within 49/21.
6. Clearance:
ConocoPhillips confirms that we along with BP and EOG agree that DECC is free to publish
any or all data contained here-in.
7. Maps & Figures:
Location Map
License P.039
Block 49/21
-1200
-1200
-1200
-1200
-1200
-1200
-1200-1200
-1200-1200
-1200
-1600
-1200
-1500
-1500
-1500
-1500-1700
-1700
-17
00
-1300
-1300-1300
-1300
-1300 -1300
-1300
-1300
-1400
-1400
-1400
-1400
-1400
-1400
-1400
-1400
-1500
-1500
-1500
-1500
-1500
-1500
-1500
-1600
-1600
-1600
-1600
-1600
-1600
49/21-3
49/21-1
49/21-8A
49/21-10
49/21-9Z
436000 440000 444000
436000 440000 444000
X, [m]
5892000
5896000
5900000
5904000
5908000
5892000
5896000
590000
05904000
5908000
Y, [m
]
436000 440000 444000
436000 440000 444000
X, [m]
5892000
5896000
5900000
5904000
5908000
5892000
5896000
590000
05904000
5908000
Y, [m
]
434000 436000 438000 440000 442000 444000 446000
434000 436000 438000 440000 442000 444000 446000
58
900
00
58
92
00
05
894
00
05
896
00
05
898
00
05
900
00
05
902
00
05
90
400
05
90
600
05
90
800
059
10
00
0
589
000
05
892
00
05
894
00
05
896
00
05
898
000
59
00
000
59
02
000
59
040
00
59
060
00
59
080
00
59
100
00
0 1000 2000 3000 4000 5000m
1:100000
Time Structure Map – Block 49/21
49/21-8A
Vulcan
49/21-3
49/21-9z
2’ 00”E 2’ 12”E
53’ 10”N
53’ 20”N
49/21-10z
Vulcan East
49/21-5
49/21-1
South Valiant
Line of Section
49/21-7
Illustrative Seismic Time line – Block 49/21
49/21-1 49/21-8A 49/21-5
Top Chalk
Rot Halite
Top Zechstein
Top Winterton
Top BasalAnhydrit
Top Rotliegendes
SW NE