+ All Categories
Home > Documents > Strat Plays of UKCS

Strat Plays of UKCS

Date post: 28-Nov-2014
Category:
Upload: adeyinka-olufemi-damilola
View: 406 times
Download: 3 times
Share this document with a friend
10
Promote United Kingdom 2011 Stratigraphic plays of the UKCS Modified after Stoker et al. (2006) Paleogene Post-rift Syn-rift Pre-rift Upper Cretaceous Lower Cretaceous Upper Jurassic Middle Jurassic Triassic - Lower Jurassic Palaeozoic Structural: drape across fault blocks and salt structures. Combination: combined dip and stratigraphic pinchout traps, combined palaeogeomorphic and basement drape traps. Stratigraphic: detached basin-floor channel and fan mounds. Structural: e.g. Forties, Montrose, Andrew, Machar, Foinaven Combination: e.g. East Foinaven, Gannet F, Schiehallion Stratigraphic: e.g. Alba, Frigg, Everest, Gryphon, Harding, Pilot Structural: e.g. Kyle, Banff, Orion Combination: e.g. Joanne, Fife, Flora Structural: e.g. Hannay, Victory Combination: e.g. Britannia, Captain, Claymore, Cromarty, Goldeneye, Scapa, Stratigraphic: e.g. Highlander Structural: e.g. Durward, East Brae, Janice, Piper, Renee, Solan, Telford Combination: e.g. Kittiwake, Magnus, South, Central & North Brae Stratigraphic: e.g. Dauntless, Highlander, Miller, Tartan Structural: e.g. Beatrice, Beinn, Brent, Ninian, Seagull Combination: e.g. Beryl Structural: e.g.Beryl, Esmond, Hewett, Judy, Marnock, Morecambe, Statfjord Combination: e.g. Kittiwake, Strathmore Structural: e.g. Argyll, Buchan, Clair, Innes, Leman, Murdoch Combination: e.g. Auk, Tyne complex, Murdoch K (CMS-III), Ravenspurn North Existing UKCS fields and discoveries are located mainly within structural traps. However, an increasing number of traps have been shown to include a component of stratigraphic entrapment by low porosity reservoir units following post-charge trap tilting. The Danish sector’s Halfdan Field is a ‘stratigraphic’ dynamic constriction trap. Many successfully tested structural closures have been found to have an element of stratigraphic entrapment, i.e. hydrocarbon- water contact is deeper than spill point. The Scapa Field is a combination syncline and stratigraphic pinchout trap that was only discovered by accident during appraisal drilling on the Claymore Field. Trap type is highly variable. Many of the combination traps were initially interpreted to be structural traps (e.g. Brae fields). Deep- water sandstone reservoirs commonly have an element of stratigraphic trapping; shallow-marine sandstones occur mainly in structural traps. Structural trap types predominate. Simple and complex tilted or horst fault block traps; crestal slumping and degradation is common in the Brent province (East Shetland Basin). Successful hanging-wall traps are relatively uncommon. Structural trap types predominate. Simple and complex tilted horst fault block traps; successful hanging-wall traps are relatively rare. Commonly found stacked in the same trap with overlying Middle Jurassic reservoirs. Triassic (Skagerrak Formation) reservoirs in Central North Sea occur in salt- controlled mini-basins. Almost entirely structural traps found. Reservoirs range from fractured basement rocks, through Devonian, Carboniferous and Permian strata. Introduction The majority of the fields and significant discoveries on the United Kingdom Continental Shelf (UKCS) are found in structural traps, with just 13% in combination structural/stratigraphic traps and only 7% in stratigraphic traps (Fig. 1). With respect to existing fields and discoveries, stratigraphic and combination traps occur mainly within Upper Jurassic syn- and post-Jurassic post-rift play fairways (Fig. 2). Fields and discoveries within pre-rift play fairways (Middle Jurassic and older) occur predominantly in structural traps. Although mounded deep-water channel and fan traps are in part structural, since differential compaction often results in 4-way dip closures, the origin of such traps is stratigraphic, and they are designated as such in this evaluation. Many tilted fault block traps have eroded crests, and thereby include a component of stratigraphic entrapment, but most of such traps are essentially structural. What proportion of the yet-to-find resources on the UKCS is located within stratigraphic or combination traps, and in which plays are these traps most likely to occur? The sheet-like geometry and sand-rich nature of many of the pre-rift reservoirs (Fig. 3) make stratigraphic entrapment unlikely. Exceptions are combination traps like the Carboniferous Tyne gas field complex, where the trap is defined by a combination of dip closure and erosional pinch-out of late Westphalian red beds beneath the base Permian unconformity. The Ravenspurn North Field is an example of a combination stratigraphic pinchout/dip trap at the margin of the Rotliegend (Lower Permian) play. The geometry and lateral distribution of deep-water mass flow deposits are highly conducive to full or partial stratigraphic entrapment; 50% of deep-water syn-rift reservoirs are located within stratigraphic and combination traps. Major recent discoveries like Buzzard, an Upper Jurassic stratigraphic pinchout/dip trap, are obvious analogues for future syn-rift targets, but these require the development of a strong conceptual model. Structural traps Combination traps Stratigraphic traps Fig. 1 Proportion of trap types in UKCS fields and discoveries (end 2008 data) Fig. 2 Proportion of trap types in UKCS fields and discoveries (end 2008 data) 7% 13% 80% Lead 132/8A: an Eocene slope channel mass-flow sandstone trap Several examples of Eocene channel systems are clearly imaged on seismic data from the eastern slope margin and floor of the Rockall Basin. The Tobermory gas discovery has been made within contemporary basin-floor fan deposits in the Faroe-Shetland Basin. For the Rockall Basin examples, the presence of an effective migration route from Jurassic and/or unproven mid-Cretaceous source rocks is the principal exploration risk. Maureen Fm Heimdal Mbr Lista Fm Lista Fm Shetland Group Devonian resting on Caledonian basement Mariner, 9/12-3 & 9/12-3 9/12b-6 9/2-1 9/3-1 & 9/21-2 Gryphon, Harding Frigg, Nuggets Heimdal Mbr Dornoch Fm Mousa Fm Top T50 Top T45 Teal Mbr Hermod Mbr Sele Fm Teal (& Hermod) Mbrs Frigg Mbr Top T30 Top T20 Top T60 Base T20 Top T60 Balder Fm SW NE VIKING GRABEN EAST SHETLAND PLATFORM Slope Basin-floor fan Sandy Delta Front / Shallow Shelf Sandy Braid Delta Depositional system Regional sequence boundary Stratigraphic trap Combination trap Prodelta / Basin Horda Fm EOCENE Bressay PALEOCENE C E A O T US E R C R E P P U Fig. 5 Schematic sequence stratigraphic section showing Paleogene depositional system and trap types, Northern North Sea Lead 132/8A UK Northern North Sea Fig. 6 Seismic attribute map (RMS amplitude within a window 10-300 ms above the top Balder Formation) showing the limit of a stratigraphic trap, Lead 132/8A. High amplitudes are interpreted as due to the presence of Eocene mass-flow sandstones within slope channels. See more of Lead 132/8A 132/9 132/8 56°40N 56°50N 9°24W 9°36W Lead 132/8A 2 km MC3D seismic data courtesy of PGS Yellow / red = high amplitude Blue = low amplitude Paleogene stratigraphic plays Half of all Paleogene UKCS hydrocarbon discoveries occur in traps with full or partial stratigraphic entrapment (Fig 2). This is because the majority of Paleogene reservoirs are deep-water sandstones, whose geometry commonly lends itself to stratigraphic entrapment. Stratigraphic pinch-out traps generally occur where Paleogene sandstones onlap and pinchout onto the flanks of basin-margin highs, as exemplified by the Everest and Fleming fields adjacent to the Jaeren High in the Central North Sea (O'Connor and Walker 1993) and the Laggan discovery on the eastern margin of the Faeroe-Shetland Basin. Combination traps offer the best potential, as a link to structure dramatically increases a stratigraphic prospect's chance of success. The most promising traps tend to either have a palaeogeomorphic component or are linked to an amplitude or AVO anomaly. The use of AVO has had mixed success in the West of Shetland area, where true Class III (increasing amplitude with offset angle) anomalies have proved elusive. In the future, the use of electromagnetic imaging techniques may be important in the further derisking of stratigraphic traps. In the Faroe-Shetland Basin, the search for stratigraphic traps has concentrated on Vaila Formation (Paleocene) sandstones beneath the Kettla Tuff, which, with adjacent claystones, acts as a regional seal. The reservoirs are known informally in BP T-zone terminology as the T31-T35 sandstones. In the Judd Sub-basin, the Foinaven Field, in stratigraphically equivalent strata, is a faulted anticline with elements of stratigraphic pinch- out on its south-east margin. Stratigraphic or combination traps are the focus of current Paleogene exploration in the North Sea, where only small 4-way dip Paleogene traps remain untested. They form a particularly important component of remaining Paleogene prospects along the Atlantic Margin province, where they have the potential to contribute significantly to the remaining 8.2 bboe undiscovered reserves currently predicted by DECC (2009; ) for this province. web-link
Transcript

PromoteUnited Kingdom

2011

Stratigraphic plays of the UKCS5650N 132/8

Paleogene stratigraphic plays Introduction

Fig. 1 Proportion of trap types in UKCS Carboniferous Tyne gas field complex,search the trap is defined by a combination of dip In the Faroe-Shetland Basin, the where for stratigraphic traps has fields and discoveries (end 2008 data) closure and erosional pinch-out of late Westphalian red beds beneath the base Permian concentrated on Vaila Formation (Paleocene) sandstones beneath the 5640N unconformity. The Ravenspurn North Field is an example of a combination stratigraphic Kettla Tuff, which, with adjacent claystones, acts as a regional seal. The Yellow / red = high amplitude pinchout/dip trap at the margin of the Rotliegend (Lower Permian) play. The geometry reservoirs are known informally in BP T-zone terminology as the T31-T35 2 km Blue = low amplitude and lateral distribution of Sub-basin, the Foinaven Field, inare highly conducive to full or sandstones. In the Judd deep-water mass flow deposits stratigraphically MC3D seismic data courtesy of PGS partial stratigraphicis a faulted anticline with elements of stratigraphic pinchequivalent strata, entrapment; 50% of deep-water syn-rift reservoirs are located within stratigraphic and combination traps. Major recent discoveries like Buzzard, an Upper Fig. 6 Seismic attribute map (RMS amplitude within a window out on its south-east margin. Jurassic stratigraphic pinchout/dip trap, are obvious analogues for future syn-rift targets,ms above the top Balder Formation) showing the limit of 10-300 Stratigraphic or combination traps are the but these require the development of a strong conceptual model. a stratigraphic trap, Lead 132/8A. High amplitudes are focus of current Paleogene exploration in the interpreted as due to the presence of Eocene mass-flow North Sea, where only small 4-way dip sandstones within slope channels. See more of Lead 132/8A Structural: e.g. Forties, Montrose, Andrew, Northern Paleogene traps remain untested. They form Lead North Machar, Foinaven Structural: drape across fault blocks and salt structures. 132/8A Sea a particularly important component of dip and stratigraphic pinchout traps, Lead 132/8A: an Eocene Gannet channel mass-flow Combination: e.g. East Foinaven, slope Combination: combined Paleogene remaining Paleogene prospects palaeogeomorphic and basement drape traps. F, Schiehallion combined along the sandstone trap Alba, Frigg, Everest, Stratigraphic: e.g. Atlantic Margin province,Stratigraphic: detached basin-floor channel and fan mounds. where they have Gryphon, Harding, Pilot the potential to contribute significantly to the Several examples of Eocene channel systems are clearly imaged remaining 8.2 bboe undiscovered reserves discoveries are located mainly within Existing UKCS fields and on seismic data from the eastern slope margin and floor of the currently predicted by DECC (2009; structural traps. However, an increasing number of traps have Structural: e.g. Kyle, Rockall Basin. The Banff, Orion Upper web-link) for this province.been shown to include a component of stratigraphic entrapment Combination: e.g.Tobermory gas discovery has been made within Joanne, Fife, Flora UK contemporary basin-floor fan deposits in the Faroe-Shetland Basin. Cretaceous by low porosity reservoir units following post-charge trap tilting. The Danish sectors Halfdan Field is a stratigraphic dynamic For the Rockall Basin examples, the presence of an effective constriction trap. migration route from Jurassic and/or unproven mid-Cretaceous source rocks is the principal exploration risk. Many successfully tested structural closures have been found to936W

Half of all Paleogene UKCS hydrocarbon discoveries occur in traps with The majority of the fields and significant discoveries on the United Kingdom Continental full or (UKCS) are found in structural 2). This iswith justthe majority combination Shelf partial stratigraphic entrapment (Fig traps, because 13% in of Paleogene reservoirs are deep-water sandstones, whose geometry structural/stratigraphic traps and only 7% in stratigraphic traps (Fig. 1). commonly lends itself to stratigraphic entrapment. Stratigraphic pinch-out With respect to existing fields and discoveries, stratigraphic and combination traps occur traps generally occur where Paleogene sandstones onlap and pinchout mainly within Upper Jurassic syn- and post-Jurassic post-rift play fairways (Fig. 2). Fields onto the flanks of basin-margin highs, as exemplified by the Everest and and discoveries within pre-rift play fairways (Middle Jurassic and older) occur Fleming fields adjacent to the Jaeren High in the Central North Sea predominantly in structural traps. (O'Connor and Walker 1993) and the Laggan discovery on the eastern Althoughofmounded deep-waterBasin. margin the Faeroe-Shetland channel and fan traps are in part structural, since differential compaction often results in 4-way dip closures, the origin of such traps is Combination traps offer the best potential, as a link to structure stratigraphic, and they are designated as such in this evaluation. Many tilted fault block dramatically increases a stratigraphic prospect's chance of success. The traps have eroded crests, and thereby include a component of stratigraphic entrapment, most promising traps tend to either have a palaeogeomorphic component but most of such traps are essentially structural. or are linked to an amplitude or AVO anomaly. The use of AVO has had What proportion ofin the West of Shetlandon the UKCS is true Class III stratigraphic mixed success the yet-to-find resources area, where located within or combination traps, and in which angle) anomalies have proved elusive. In (increasing amplitude with offset plays are these traps most likely to occur? the future, the use of electromagnetic imaging techniques may be The sheet-like geometry and sand-rich nature of many of the pre-rift reservoirs (Fig. 3) important in the further derisking unlikely. Exceptions are combination traps like the make stratigraphic entrapment of stratigraphic traps.

13%

7%

132/9

80%

Structural traps Combination trapsLead 132/8A Stratigraphic traps

Post-rift

SW

Lower Cretaceous

have an element of stratigraphic entrapment, i.e. hydrocarbonwater contact is deeper than spill point. The Scapa Field is a combination syncline and stratigraphic pinchout trap that was only discovered by accident during appraisal drilling on the Top T60 Claymore Field.

Structural: e.g. Hannay, Victory Combination: e.g. Britannia, Captain, Claymore, Cromarty, Goldeneye, Scapa, Stratigraphic: e.g. Highlander

924W

NE

9/12-3Syn-rift

VIKING GRABENFrigg, Nuggetsp To T60Frigg Mbr

Top T50

Bressay

Upper Jurassic

Mousa Fm Trap type is highly variable. Many of the combination traps were Structural: e.g. Durward, East Brae, Janice, Piper, Renee, Solan, Telford initially interpreted to be structural traps (e.g. Brae fields). DeepBalder Fm Combination: e.g. Kittiwake, Magnus, water sandstone reservoirs commonly have an element of South, Central & North Brae EOCENE 9/3-1 & stratigraphic trapping; shallow-marine sandstones occur mainly Mbr Hermod Stratigraphic: e.g. Dauntless, Highlander, in structural traps. 9/21-2 Miller, Tartan To Gryphon, p Dornoch Fm T45

Middle 9/2-1 Jurassic

Pre-rift

Mariner, 9/12-3 & 9/12b-6 Triassic

Harding Structural: e.g. Beatrice, Beinn, Brent, Structural trap types predominate. Simple and complex tilted or Horda Fm Heimdal horst fault block traps; crestal slumping and degradation is Mbr Ninian, Seagull common in the Brent province (East Shetland Basin). Successful Combination: e.g. Beryl Teal (& Hermod) Mbrs hanging-wall traps are relatively uncommon. Teal Mbr Sele Fm Lista Fm

Top T30

EAST SHETLAND PLATFORM

Structural trap types predominate. Simple and complex tilted horst Devonian fault block traps; successful hanging-wall traps are Heimdal Mbr e.g.Beryl, Esmond, Hewett, Structural: Top T20 resting relatively rare. Commonly found stacked in the same trap with on Judy, Marnock, Morecambe, Statfjord Lower Jurassic overlying Middle Jurassic reservoirs. Triassic (Skagerrak Lista Fm Caledonian Combination: e.g. PALEOCENE Kittiwake, Strathmore Formation) reservoirs in Central North Sea occur in saltbasement controlled mini-basins. roup tland G ETACEOUS She R RC Structural: e.g. Argyll, Buchan, Clair, Innes, PE Maureen Fm Almost entirely structural traps found. Reservoirs range from Leman, P UMurdoch Depositional system Palaeozoic fractured basement rocks, through Devonian, Carboniferous and Combination: e.g. Auk, Tyne complex, Permian strata. Ravenspurn 0 Murdoch K (CMS-III), Sandy Braid Delta T2 North eas

B Regional sequence boundary Fig. 2 Proportion of trap types in UKCS fields and discoveries (end 2008 data)

Sandy Delta Front / Shallow Shelf Slope Basin-floor fan Prodelta / Basin

Modified after Stoker et al. (2006)

Stratigraphic trap Combination trap

Fig. 5 Schematic sequence stratigraphic section showing Paleogene depositional system and trap types, Northern North Sea

PromoteUnited KingdomAGE NEOGENE

2011ATLANTIC MARGIN

Stratigraphic plays of the UKCS

CENTRAL AND NORTHERN NORTH SEA

SOUTHERN NORTH SEA

PALEOGENE

CRETACEOUS

POST-RIFTSYNRIFT

?

JURASSIC

TRIASSIC PERMIAN

CARBONIFEROUS

DEVONIAN?

PRE-RIFT

PRE-DEVONIAN

Proven reservoir unit Source rock unit Evaporite Volcanics Basement

Sandstone (fluvial/aeolian) Sandstone/mudstone/coal (deltaic) Sandstone (shallow-marine)

Sandstone (basin-floor) Carbonate Mudstone

Fig. 3 Simplified stratigraphy and lithofacies in UKCS oil and gas basins

100 Structural trapsFig. 4 Field size distribution chart for UKCS fields and discoveries in structural traps, and in stratigraphic and combination traps (end 2008 statistics). The relatively flat to irregular distribution for the stratigraphic and combination trap population is suggestive of an immature population. Modified after Stoker et al. 2006.

Number of discoveries

80

Stratigraphic & combination traps

60

40

20

04-8 8-16 16-32 32-64 64128 128256 256- 5121024- >2048 512 1024 2048

Field/discovery size (x106 BOE in place)

Reference:Stoker, SJ, Gray, JC, Haile, P, Andrews, IJ & Cameron, TDJ. 2006. The importance of stratigraphic plays in the undiscovered resources of the UK Continental Shelf. In: Allen, M.R., Goffey, G.P., Morgan, R.K. & Walker, I.M. (eds). The Deliberate Search for the Stratigraphic Trap. Geological Society, London, Special Publication, 254, 153-167.

PromoteUnited Kingdom

2011

Stratigraphic plays of the UKCS5650N 132/8 132/9

Paleogene stratigraphic playsHalf of all Paleogene UKCS hydrocarbon discoveries occur in traps with full or partial stratigraphic entrapment (Fig 2). This is because the majority of Paleogene reservoirs are deep-water sandstones, whose geometry commonly lends itself to stratigraphic entrapment. Stratigraphic pinch-out traps generally occur where Paleogene sandstones onlap and pinchout onto the flanks of basin-margin highs, as exemplified by the Everest and Fleming fields adjacent to the Jaeren High in the Central North Sea (O'Connor and Walker 1993) and the Laggan discovery on the eastern margin of the Faeroe-Shetland Basin. Combination traps offer the best potential, as a link to structure dramatically increases a stratigraphic prospect's chance of success. The most promising traps tend to either have a palaeogeomorphic component or are linked to an amplitude or AVO anomaly. The use of AVO has had mixed success in the West of Shetland area, where true Class III (increasing amplitude with offset angle) anomalies have proved elusive. In the future, the use of electromagnetic imaging techniques may be important in the further derisking of stratigraphic traps. In the Faroe-Shetland Basin, the search for stratigraphic traps has concentrated on Vaila Formation (Paleocene) sandstones beneath the Kettla Tuff, which, with adjacent claystones, acts as a regional seal. The reservoirs are known informally in BP T-zone terminology as the T31-T35 sandstones. In the Judd Sub-basin, the Foinaven Field, in stratigraphically equivalent strata, is a faulted anticline with elements of stratigraphic pinchout on its south-east margin. Stratigraphic or combination traps are the focus of current Paleogene exploration in the North Sea, where only small 4-way dip Paleogene traps remain untested. They form a particularly important component of remaining Paleogene prospects along the Atlantic Margin province, where they have the potential to contribute significantly to the remaining 7.3 bboe undiscovered reserves currently predicted by DECC (2010; web-link) for this province.

Lead 132/8A

936W

924W

Yellow / red = high amplitude Blue = low amplitude

5640N 2 km MC3D seismic data courtesy of PGS

Lead 132/8A

Northern North Sea

Fig. 6 Seismic attribute map (RMS amplitude within a window 10-300 ms above the top Balder Formation) showing the limit of a stratigraphic trap, Lead 132/8A. High amplitudes are interpreted as due to the presence of Eocene mass-flow sandstones within slope channels. See more of Lead 132/8A

Lead 132/8A: an Eocene slope channel mass-flow sandstone trapSeveral examples of Eocene channel systems are clearly imaged on seismic data from the eastern slope margin and floor of the Rockall Basin. The Tobermory gas discovery has been made within contemporary basin-floor fan deposits in the Faroe-Shetland Basin. For the Rockall Basin examples, the presence of an effective migration route from Jurassic and/or unproven mid-Cretaceous source rocks is the principal exploration risk.NE

UK

SWTop T60

9/12-3 Bressay

VIKING GRABENBalder FmHermod Mbr

Top T50

Mousa Fm

9/3-1 & 9/21-2Dornoch Fm Heimdal Mbr

EOCENE

To p

T4

5

Gryphon, HardingTeal Mbr

Frigg, NuggetsHorda FmTeal (& Hermod) Mbrs

p To

T60

9/2-1 Mariner, 9/12-3 & 9/12b-6

Frigg Mbr

Lista Fm Devonian resting on Caledonian basement

Sele FmTop T30

Heimdal Mbr

Top T20

PALEOCENEn TACEOUS Shetla CRE R d Group

Lista Fm

EAST SHETLAND PLATFORMRegional sequence boundary Stratigraphic trap Combination trap

Maureen FmT2 0

PE UPse

Depositional systemSandy Braid Delta Sandy Delta Front / Shallow Shelf Slope Basin-floor fan Prodelta / Basin

Ba

Fig. 5 Schematic sequence stratigraphic section showing Paleogene depositional system and trap types, Northern North Sea

PromoteUnited Kingdom

2011

Stratigraphic plays of the UKCSSWInterlobe area drilled by 22/9-1 six years before discovery of the field

The Everest Field: a successful stratigraphic pinch-out trap, Central North SeaThe Everest Field is a complex of laterally-offset, stacked gas-condensate reservoirs in the Paleocene Maureen Formation and Mey (Andrew) and Forties Sandstone Members where they pinch out laterally on the western flank of the Jaeren High, in the Central North Sea (Fig. 7). The Forties Sandstone Member is separated into two lobes by an interlobe area of sand-poor sediments that was drilled in 1975 by the first exploration well (22/9-1), hence delaying discovery of the field.

NEDepth (feet) 8500

GWC

Forties

OWC

GOC 9000

MeyLaggan discovery

Maure

en

Upper Cretaceous Chalk Group

9500

10000

Everest Field

TriassicLower Cretaceous

Jaeren High

UK

Fig. 7 Geoseismic section across the Everest Field (after OConnor and Walker, 1993)

The Laggan gas discovery: a successful stratigraphic trap with an associated amplitude anomaly, FaroeShetland BasinShell well 206/1-2 discovered the Laggan gas accumulation in 1986. Ten years later Total drilled a second well on Laggan (206/1-3 was located 4 km to the southwest of 206/1-2). Both wells encountered gas within good quality sequence T35 sands. T35 sands have high porosity, high permeability, and have ubiquitous chlorite grain coating, enhancing porosity of the sands. Currently, it is difficult to separate out anomalously high seismic amplitudes associated with gas to those related to the high porosity but water-wet sandstone. High amplitudes extend beyond the GWC. The updip limit of the gas accumulation is a pinch-out against a northeast trending growth fault, which also coincides with the high amplitude cutoff (Figs. 8 & 9).

205/5b Chevron

NW206/2b

206/1-3

SE

TWT (Secs) 1

205/5a Total

Top Balder FmFi gu re 9

2

Laggan amplitude anomalyMap courtesy of Total

Top Kettla Tuff

3

Fig. 8 Laggan amplitude anomaly

Top Cretaceous206/1-3 2 km4

Seismic data courtesy of Total

Fig. 9 Seismic section across the Laggan gas discovery

Paleogene references:Ahmadi, ZM, Sawyers, M, Kenyon-Roberts, S, Stanworth, CW, Kugler, KA, Kristensen, J, and Fugelli, EMG. 2003. Paleocene. 235-259 in The Millennium Atlas: petroleum geology of the central and northern North Sea. Evans, D, Graham, C, Armour, A, and Bathurst, P (editors and coordinators). (London: The Geological Society of London) Jones, E, Jones, R, Ebdon, C, Ewen, D, Milner, P, Plunkett, J, Hudson, G, and Slater, G. 2003. Eocene. 261-277 in The Millennium Atlas: petroleum geology of the central and northern North Sea. Evans, D, Graham, C, Armour, A, and Bathurst, P (editors and coordinators). (London: The Geological Society of London) OConnor, SJ, and Walker, D. 1993. Paleocene reservoirs of the Everest trend. In: Parker, JR (ed.) Petroleum Geology of Northwest Europe: Proceedings of the 4th Conference. The Geological Society, London, pp. 145-160. Underhill, JR. 2001. Controls on the genesis and prospectivity of Paleogene palaeogeomorphic traps, East Shetland Platform, UK North Sea. Marine and Petroleum Geology, Vol. 18, pp. 259281.

PromoteUnited KingdomW 132/17Block

2011

Stratigraphic plays of the UKCSBlock 132/18 Lead 132/18A Block 132/19

ETWT (s)

Top Balder Formation

3.5

Upper Cretaceous sandstone stratigraphic play, Atlantic MarginDrilled and undrilled Cenomanian/Turonian sandstone (Commodore Formation; Ritchie et al. 1996) three-way dip closed and stratigraphic traps have been documented in the Faroe-Shetland Basin (Grant et al. 1999, Loizou et al. 2006). Here, Commodore Formation sandstones 1010 ft thick were initially encountered in well 206/3-1, and follow-up well 206/4-1 proved a gross sandstone thickness of 1786 ft. The sandstone interval penetrated by these wells corresponds to a reflective package on seismic data, and seismic attribute mapping showed the sandstone distribution to be in a set of lobate bodies interpreted as submarine fans (Grant et al. op. cit.). These fans lie in the hanging-wall of the Rona Ridge, and were shed northwestwards off the ridge. On the basis of seismic attribute mapping, Loizou et al. (2006) identified an analogous untested potential Upper Cretaceous sandstone stratigraphic trap on the western side of the Corona Ridge (Lead 213/20A).924W

Top Cretaceous Sill

4.0

Sill High amplitude intraUpper Cretaceous event may represent highdensity turbidite sandstones analogous to those of Turonian age in the FaroeShetland Basin (Grant et al.1999).

4.5

Sill

?Intra Lower Cretaceous

Top basement

?Near base Cretaceous

5.0

MC3D seismic data courtesy of PGS

2 km

Fig. 10 W-E seismic profile across Lead 132/18A, an intra-Upper Cretaceous (?Cenomanian-Turonian) deep water mass-flow sandstone trap in the South Rockall Basin identified from a seismic amplitude anomaly adjacent to the basin-margin.Lead 213/20ic nt in tla arg A M

206/3-1 206/4-1

936'W

Lead 132/18A

132/18

132/19

UK

Lead 132/18A

Seismic mapping across block 132/18 in the South Rockall Basin has enabled the recognition of another intra-Upper Cretaceous amplitude anomaly (Figs. 10 & 11). The area of high amplitudes has a lobate shape located in the hanging-wall of the basin margin fault, and it is interpreted to represent overlapping slope-fan lobes shed westwards off the adjacent Outer Hebrides Platform. These interpreted Upper Cretaceous fan sandstones in block 132/18 lie in a structural setting directly analogous to the fan sandstones proven by well 206/3-1 and 206/4-1 in the FaroeShetland Basin adjacent to the Rona Ridge. They form the basis for Lead 132/18A featured on the Promote UK 2010 CD.

Sill

132

2 km

Fig. 10UK Ireland

Seismic survey join5620'N

SillUpper Cretaceous references:Grant, N., Bouma, A. & McIntyre, A. 1999. The Turonian play in the Faroe-Shetland Basin. In: Fleet, A.J. & Boldy, S.A.R. (eds) Petroleum Geology of Northwest Europe: Proceedings of the 5th Conference, 661-673. Geological Society, London. Loizou, N., Andrews, I.J., Stoker, S.J. & Cameron, D. 2006. West of Shetland revisted: the search for stratigraphic traps. In: Allen, M.R., Goffey, G.P., Morgan, R.K. & Walker, I.M. (eds) The Deliberate Search for the Stratigraphic Trap. Geological Society, London, Special Publications 254, 225245. Ritchie, J.D., Gatliff, R.W. & Riding, J.L. 1996. The Lithostratigraphy of the pre-Tertiary of the North West Margin, British Geological Survey, Edinburgh.

Yellow / red = high amplitude Purple / blue = low amplitude

MC3D seismic data courtesy of PGS

Fig. 11 Seismic attribute map (amplitude extraction at intra-Upper Cretaceous horizon) showing an amplitude anomaly that is ascribed to the presence of Late Cretaceous (?Cenomanian/Turonian) mass-flow sandstones within overlapping slope-fan lobes. See section 4 of Promote UK 2011 CD for details of this lead (click here).

PromoteUnited Kingdom

2011

Stratigraphic plays of the UKCSFig. 12 Late Ryazanian-Barremian fairwayShetland Platform

Lower Cretaceous stratigraphic plays76% of UKCS Lower Cretaceous fields and discoveries are located within combination or stratigraphic traps. The limited lateral and vertical distribution of coarse clastics within the Lower Cretaceous section gives considerable opportunity for full or partial stratigraphic entrapment. The massflow genesis of much of the Lower Cretaceous coarse-clastic sediment means that mounding, enhanced by differential compaction, provides the mechanism for palaeogeomorphic entrapment. The Scapa and Britannia fields and the Lower Cretaceous part of the Highlander Field were found by serendipity during drilling to deeper, structural Jurassic targets. Each of these discoveries is located within a low or syncline, and has a strong stratigraphic trapping component. Since seismic imaging of Lower Cretaceous sandstones in the North Sea is commonly poor, a robust depositional model must be developed from well and other data, or more sophisticated seismic techniques need to be employed. Morgan et al. (2002) and Morgan and Went (2004) showed that anomalous AVO effects can be recognised from long-offset (6 km) 3D seismic data within channel-like features and lobate, fan-like bodies, which can be implied to represent the presence of sandstones.

12

Scapa, Claymore

13

14

?

50 km

HighlanderFladen 15 Ground16 Spur

MORAY FIRTHHalibut Horst

18Blake

19Scotland

FortiesMontrose High

22

20

21East Central Graben

West Central Shelf

West Central Graben

25

26

27

28Study area

29

Auk High

Latest Ryazanian-BarremianShallow marine shelf / slope Mass flow sandstone (modified after Copestake et al. 2003) Possible mass flow sandstone (this study)

Devils Hole Sandstone Member

30

Hinterland / intra-basinal high (erosion or non-deposition) Field / discovery Possible sediment transport route

The established Lower Cretaceous deep-marine Deep marine basin sandstone play fairway of the UK North Sea is mostly limited to the Moray Firth basins (Figs. 12 & 13). Shallow shelf sandstone Although Lower Cretaceous sandstones have been found in 131 wells within the UK Central Graben area outside the established fairways, there has been little direct exploration of this play in those areas. MiltonWorssell et al. (2006) suggest that the potential exists for at least 26 undrilled Lower Cretaceous deep-water Fig. 13 Aptian-Albian fairway stratigraphic leads in the Central Graben area.Shetland Platform

12

13 MORAY

14

Goldeneye, Hannay SaltireFladen Ground Spur

50 km

16

Captain

15

Halibut Horst

FIRTH 18See also poster: Lower Cretaceous deep-water sand plays, UK Central GrabenBlakeScotland

Witch Ground Graben Fisher Bank Basin

Britannia

South Buchan Basin

BrodgarFMH

19

20

21

22East Central Graben

Cromarty, Atlantic

West Central Shelf

25

West Central Graben

26

27

28Study area

29Auk High

30

Aptian-Albian playKey as above, except for right Possible mass flow sandstone (modified after Oakman 2005)

PromoteUnited Kingdom

2011

Stratigraphic plays of the UKCS5 km Fladen Ground Spur16/2 16/3

Upper Jurassic deep-water sandstone stratigraphic playsUpper Jurassic sandstones are widely developed in the UKCS rift basins; however, the earliest Upper Jurassic sandstones (e.g. Piper and Fulmar formations) are deltaic to shallow-marine sediments that pre-date the main rifting phase. Syn-rift clastics are predominantly deep-water mass-flow deposits (e.g. Brae Formation and Burns and Claymore Sandstone members in the Viking Graben and Moray Firth), whose lateral distribution and geometry is highly conducive to at least partial stratigraphic entrapment. Upper Jurassic syn-rift clastics are interbedded with the Kimmeridge Clay Formation, a world-class oil source rock that has generated much of the oil in the North Sea. Fraser et al. (2003) have summarised the range of trap types in which Upper Jurassic reservoirs have been found. The Brae complex and Miller fields are examples of combined structural and stratigraphic pinch-out traps that were originally conceived to be structural traps. In the South Viking Graben, Upper Jurassic coarse clastics of the Brae Formation form a number of overlapping fan bodies (Figs. 17 & 18). The South, Central and North Brae fields were initially obvious targets, since each has substantial 4-way dip closure due to compactional drape. However, testing of the Brae structures found that the oil-water contacts were much deeper than the spill point of the structural closures mapped, and appraisal drilling confirmed the importance of stratigraphic pinch-out at these fields (Roberts 1991, Stephenson 1991, Turner & Allen 1991). Many of the Upper Jurassic deep-water sandstone reservoirs within stratigraphic pinchout traps are located above an underlying structural trap (e.g. Hot Lens reservoir of the Tartan Field, Fig. 19). Predicting the distribution and pinch-out of such deep-water sandstones is critical to this play, and relies on the development of a well-grounded conceptual model since these reservoirs are typically poorly-resolved on seismic data. The discovery of the large Buzzard Field, a stratigraphic pinch-out trap located on the southern margin of the Moray Firth Basin (Dor 2002), is a testament to the potential for spectacular success in this play. Fraser et al. (2003) suggest that Upper Jurassic deep-water reservoirs may be the most important exploration play for the future.

East Brae

North Brae Central Brae Miller16/7

Kingfisher

South Brae

16/8

Larch

South Viking Graben

Oil field Condensate field

Fig. 17 Overlapping Upper Jurassic fans of the Brae-Miller area, South Viking GrabenIncorporating information from: Garland (1993), Roberts (1991), Stephenson (1991) and Turner & Allen (1991)

fault

zone

1 km

argin

Central Brae

16/8a 16/8c

en m

Vikin g

Grab

Miller

16/8e

Brae/ Miller16/7a

South Brae16/7b 16/7c 16/8b16/8f

Tartan Field

Dip closure

Stratigraphic pinchout

Fig. 18 Stratigraphic trapping importance at the South Brae, Central Brae and Miller fields, South Viking GrabenIncorporating information from: Garland (1993), Roberts (1991) and Turner & Allen (1991)

UK

9000 Depth (feet) 10000

South

Tartan Field upthrown blockOWC Upper Jurassic Kimmeridge Clay FormationCarbonife rous

Tartan Field downthrown blockHot Lens Upper Jurassic Piper Formation

North

9000 Depth (feet) 10000

rmity confo eous un Base Cretac

11000iferou Carbon s

11000Base Cret

Hot Lens Middle Jurassic PermoTriassic OWC

aceous unconform ity

12000

1000 ft

12000

13000

After Moseley (1999)

13000

Fig. 19 Stratigraphic entrapment of the Upper Jurassic Hot Lens reservoir at the Tartan Field, Moray Firth

Upper Jurassic deep-water references:Dor, G. 2002. The Buzzard Field - an overlooked North Sea giant. Extended abstracts, Petex 2002 CD-ROM Fraser, SI, Robinson, AM, Johnson, HD, Underhill, JR, Kadolsky, DGA, Connell, R, Johannessen, P, and Ravns, R. 2003. Upper Jurassic. 157-189 in The Millennium Atlas: petroleum geology of the central and northern North Sea. Evans, D, Graham, C, Armour, A, and Bathurst, P (editors and coordinators). (London: The Geological Society of London). Garland, CR. 1993. Miller Field: reservoir stratigraphy and its impact on development. In: Parker, JR (ed.) Petroleum Geology of Northwest Europe: Proceedings of the 4th Conference, Geological Society, London, pp. 231-240. Moseley, BA. 1999. Downthrown closures of the Outer Moray Firth. In: Fleet, AJ and Boldy, SAR (eds) Petroleum Geology of Northwest Europe: Proceedings of the 5th Conference, Geological Society, London. pp. 861-878. Roberts, MJ. 1991. The South Brae Field, Block 16/7a, UK North Sea. 49-54 in Abbotts, IL (ed.), United Kingdom Oil and Gas Fields, 25 Years Commemorative Volume, Geological Society Memoir No. 14. Stephenson. 1991. The Kopervik fairway, Moray Firth, UK. Petroleum Geoscience, Vol. 6, pp. 265-274. Turner, CC and Allen, PJ. 1991. The Central Brae Field, Block 16/7a, UK North Sea. 49-54 in Abbotts, IL (ed.), United Kingdom Oil and Gas Fields, 25 Years Commemorative Volume, Geological Society Memoir No. 14.

PromoteUnited Kingdom

2011

Stratigraphic plays of the UKCSSW1 kmTWT (s)

Upper Jurassic shallowmarine sandstone stratigraphic playUpper Jurassic shallow-marine sandstones (Fulmar Formation) occur within stratigraphic and combination traps on the West Central Shelf of the UK Central North Sea (e.g. Dauntless and Kittiwake oil fields). Fulmar Formation sandstones are thought to have been deposited within and at the edges of marine embayments that formed in response to the dissolution of underlying salt diapirs (Stewart & Clark 1999, Stewart et al. 1999, Fraser et al. 2003). In much the same way, underlying Triassic fluvial sandstones of the Skagerrak Formation are believed to have developed within palaeo-valleys located along the crests of dissolving salt walls and diapirs. Within this model of deposition, potential Triassic and Upper Jurassic sandstone reservoirs are thought to lie above the salt walls/diapirs, but not above the structurally higher minibasins or pods of Triassic mudstone which formed between the salt highs (Fig. 20; Stewart et al. 1999).

NE

0.5

Top Sele Formation

Eocene and younger

Base Cretaceous

Top Chalk Group

1.0

Top Zechstein Gp

Triassic Smith Bank Formation

Base Upper Jurassic

Lead 28/12B

Seismic data courtesy of WesternGeco

Fig. 20 Seismic line across a combination trap associated with a salt diapir (Lead 28/12A, see Fig. 21). Stratigraphic pinchout / facies change across the palaeo-low formed by salt dissolution defines the limit of the trap.000E 100E

20

21

22West Central Graben(mature Upper Jurassic source rocks)

Mapping of pseudo topography as described by Stewart et al. (1999) offers a good insight into the location of potentially attractive leads in the West Central Shelf Fulmar Formation play (Fig. 21).

Go to: Lead 28/4B Go to: Lead 28/15A

Go to: Lead 28/12B Go to: Lead 29/11A

Devils Hole Horst

Lead 28/4BData gap

Data gap

5700N

27of st ud y

28Lead 28/12B

29Lead 28/15A

Fig. 21

Upper Jurassic shallow-marine references:Fraser, SI, Robinson, AM, Johnson, HD, Underhill, JR, Kadolsky, DGA, Connel, R, Johannessen, P & Ravnas, R. 2003. Upper Jurassic. In: Evans, D, Graham, C, Armour, A, and Bathurst, P (eds), The Millennium Atlas: petroleum geology of the central and northern North Sea. Geological Society, London, 157-189. Stewart, SA & Clark, JA. 1999. Impact of salt on the structure of the Central North Sea hydrocarbon fairways. In: Fleet, AJ & Boldy, SAR (eds) Petroleum Geology of Northwest Europe: Proceedings of the 5th Conference, Geological Society, London, 179-200. Stewart, SA, Fraser, SI, Cartwight, JA, Clark, JA & Johnson, HD. 1999. Controls on Upper Jurassic sediment distribution in the Durward-Dauntless area, UK Blocks 21/11, 21/16. In: Fleet, AJ & Boldy, SAR (eds) Petroleum Geology of Northwest Europe: Proceedings of the 5th Conference, Geological Society, London, 879-896.

LiHigh

m it

UK

West Central Shelf

Lead 29/11A

Low Topography

Fig. 21 Pseudo topography of pre-Late Jurassic (cf. Stewart et al. 1999, their Fig. 19) across the West Central Shelf showing the leads located in unlicensed acreage and featuring on this Promote UK CD-ROM. Note that the apparent low topography is an artifact of the pseudo topography generation method across the Devils Hole Horst, and the south-western part of the West Central Shelf where the Zechstein comprises a thin, stable platform-type section.

PromoteUnited KingdomPermian

2011

Stratigraphic plays of the UKCSEast Midland Shelf Sole Pit Basin Silverpit Basin

Palaeozoic stratigraphic playsNearly all of the Rotliegend (Lower Permian) fields and discoveries in the UKCS are entirely structural in trap configuration due to the sheetlike aspect of the Leman Sandstone Formation. The potential for stratigraphic pinch-out traps around the basin margins is demonstrated by the cross-section and block diagram in Figures 22 and 23. To date, only the Ravenspurn North Field in the Southern North Sea Gas Basin documents the success of the stratigraphic pinch-out play, with entrapment a combination of faulting, dip, and reservoir pinch-out to the north-west (Ketter 1991). Reduced reservoir thickness and quality is a significant risk in such basinmargin pinch-out plays.Palaeotopographic high with thin, patchy aeolian sands preserved Sabkha / Silverpit lake margin

Offshore extension of Market Weighton Granite100m

50m

Inde High Dowsing Fault Zone Fluvial Aeolian Carboniferous Sabkha Playa lakeFrom: Glennie (1998)

0

Leman Sandstone Formation (reservoir)

Silverpit Formation (seal)

Fig. 22 Rotliegend Group: schematic facies development, Southern North Sea Gas Basin

Permian references:Dominant wind directionGlennie, KW. 1998. Lower Permian - Rotliegend. 137-173 in: Glennie, KW (ed.) Petroleum Geology of the North Sea: basic concepts and recent advances. Blackwell Science Ltd, Oxford. Ketter, FJ. 1991. The Ravenspurn North Field, Blocks 42/30, 43/26a, UK North Sea. In: Abbotts, IL. (ed.) United Kingdom Oil and Gas Fields, 25 Years Commemorative Volume, Geological Society Memoir 14, pp. 459-467. Munns, J.W., Gray, J.C., Stoker, S.J., Andrews, I.J. & Cameron, T.D.J. 2005. The remaining hydrocarbon potential of the UK Continental Shelf. In: Dor, AG & Vining, BA (eds) Petroleum Geology: North-West Europe and Global PerspectivesProceedings of the 6th Petroleum Geology Conference, Geological Society, London, 41-54.

Postdepositional tilt Leeward accumulation of aeolian sands Prospective reservoirou fer s

rb Ca

on

i

Windward accumulation of aeolian sands Prospective reservoir

Fig. 23 Schematic diagram to illustrate structural control on Leman Sandstone stratigraphic pinch-out trap (after Munns et al. 2005)Fig. 24

43

44

Lower Permian fairway (no Carboniferous topseal) Ketch Member (Westphalian C-D red beds sub-fairway) Westphalian C-D red beds present beneath Lower Permian fairway Westphalian coal-measure source rocks present Westphalian coal-measure source rocks absent Gas field / discovery with Ketch Member reservoir

UK

UK Neth erlan ds

CarboniferousMost of the UKCS Carboniferous fields and discoveries are in structural traps top-sealed by unconformably-overlying Permian strata. However, at the Tyne gas field complex in the Southern Gas Basin, the trap is a combination of dip and erosional truncation beneath the base Permian unconformity. Where such combination traps have no associated structural closure on the base Permian, intraformational seals are required. In the example in Figure 25, the Carboniferous reservoirs dip in the opposite direction to the base of the Permian, and only an intraCarboniferous top seal is needed. If the base Permian and Carboniferous beds dip in the same direction, an intraformational bottom seal would be required. Much of the Westphalian B interval is mud-prone, and offers good sealing capacity. The upper part of the Ketch Member (Fig. 24) is at least locally mud-prone, and likewise a good potential seal (Fig. 25). Intraformational seals within the Upper Namurian and Westphalian A are not well-developed, so the Ketch Member and Caister Sandstone unit remain the most attractive Carboniferous targets for erosional truncation traps. The heavily fault-compartmentalised configuration of the Carboniferous means that the majority of Carboniferous traps will rely to some extent upon fault seal also. Carboniferous reference:Cameron, TDJ, Munns, JR, and Stoker, SJ. 2005. Remaining exploration potential of the Carboniferous fairway, UK Southern North Sea. In: Collinson, JD, Evans, DJ, Holliday, DW & Jones, NS. (eds) Carboniferous hydrocarbon resources: the southern North Sea and surrounding areas. Occasional Publication, 7, Yorkshire Geological Society. 209-224.

Hawksley Munro

Tyne

Kelvin Rita Boulton Murdoch K Minke Orca Schooner Ketch

48

0

20 km

49

Topaz

Fig. 24 Ketch Member (Late Westphalian, Carboniferous) play fairway, Southern North Sea Gas Basin (after Cameron et al. 2005)SWUpper Permian Zechstein Group (Evaporite seal)

NESubsea depth (km) 4n ia al

Lower

Permia

n

Silverpit Fm (seal)

es W h tpes W

Caister Sandstone unit Namurian and older

Westphalian C-D red beds (Ketch Mbr)

Blia n A

Fig. 25 Potential erosional truncation stratigraphic traps (no structural closure at base Permian unconformity). Modified after Cameron et al. (2005)

tp ha

5

PromoteUnited Kingdom

2011

Stratigraphic plays of the UKCSSummary

Stratigraphic and combination traps account for only 18% of existing fields and discoveries. Many of the stratigraphic traps have been found entirely by chance whilst drilling towards other targets Few substantial undrilled structural traps remain in the UK North Sea Upper Jurassic syn-rift and Cretaceous to Paleogene post-rift deep-water plays offer the greatest potential for stratigraphic entrapment Pre-rift plays offer little stratigraphic potential, focused mainly in Carboniferous plays Deep-water sandstones with limited lateral distribution constitute the principal reservoir in stratigraphic plays. Well-grounded conceptual models for reservoir distribution are required for trap prediction. Seismic data may not adequately resolve the stratigraphic trap at the exploration phase Around 55% of the UKs undiscovered resources are predicted to lie in stratigraphic or combination traps100 Structural traps Stratigraphic & combination traps

Number of discoveries

80

Fig. 26 Field size distribution chart for UKCS fields and discoveries in structural traps, and in stratigraphic and combination traps (as of end 2008). A speculative curve shows a possible total population of accumulations within stratigraphic and combination traps, and indicates the potential field size distribution of the undiscovered resources in such traps. Modified after Stoker et al. 2006.

60Possible total population of accumulations in stratigraphic and combination traps

40

20

04-8 8-16 16-32 32-64 64128 128256 256- 5121024- >2048 512 1024 2048

Field/discovery size (x106 BOE in place)Paleogene

to-

Estimated % of total YetFind in stratigraphic and combination trapsPost-rift

Post-rift

Fig. 27 Summary of proportion of trap types in UKCS fields and discoveries and estimated proportion of total yet-tofind resources in stratigraphic and combination traps. Trap types within fields and discoveries, discovery curves and geological models for each gross play have been considered as a means of estimating the proportion of stratigraphic and combination traps in the undiscovered resource population. Modified after Stoker et al. 2006.Structural traps Combination traps Stratigraphic traps

Upper Cretaceous

33%

Lower Cretaceous

Syn-rift

Syn-riftUpper Jurassic

17%Pre-rift

Middle Jurassic

Pre-rift

Reference:Stoker, SJ, Gray, JC, Haile, P, Andrews, IJ & Cameron, TDJ. 2006. The importance of stratigraphic plays in the undiscovered resources of the UK Continental Shelf. In: Allen, MR, Goffey, GP, Morgan, RK & Walker, IM (eds). The deliberate search for the stratigraphic trap. Geological Society, London, Special Publications, 254, 153-167.

Triassic Lower Jurassic Palaeozoic

5%

The material presented on this panel is for information only. Whilst every effort has been made to ensure that the information provided is accurate, it does not constitute legal, technical or professional advice. For more information contact: Joy Gray Peter Haile Email: [email protected] Email: [email protected]


Recommended