Sand Injectites in the North Sea and the Atlantic margin Giant fields - Infill targets - Drilling hazards - Migration paths

Transcription

1 FORCE Conference: Underexplored Plays, NPD, Stavanger 8-9 April 2015 Sand Injectites in the North Sea and the Atlantic margin Giant fields - Infill targets - Drilling hazards - Migration paths Mads Huuse With unpublished interpretation input from Tobi Olobayo (PhD 2015) Basin Studies and Petroleum Geoscience Group, University of Manchester, UK mads.huuse@manchester.ac.uk

2 Stratigraphic and geographic occurrence of sand injection in the North Sea Northeast Viking Graben Late Cretaceous (Måløy slope), Late Paleocene / Early Eocene North Viking Graben Mid Eocene, Late Eocene, mid/late Miocene/Pliocene, Plio-Pleistocene South Viking Graben & Utsira High Paleocene/Eocene boundary, Early Eocene, Mid Eocene, Oligo-Miocene Outer Moray Firth Mid-Eocene, Late Eocene / early Oligocene, Miocene,?Plio-Pleistocene Northern Central Graben Early Eocene Norwegian-Danish Basin (Siri Canyon) Late Eocene / early Oligocene, mid Miocene Ringkøbing-Fyn High Late Oligocene?Southern North Sea?Pliocene Faroe-Shetland Basin Early Eocene, mid/late Miocene Møre Basin Paleocene?, Miocene Barents Sea (Sørvestnaget Basin) Eocene San Joaquin Valley (California) Late Cretaceous, Paleocene, Eocene Watch this space: Uruguay, Angola, Baffin Bay, Tanzania, New Zealand

3 ??? Mariner Gryphon Harding Alba Chestnut Jotun Balder Grane Sleipner Catcher

4 Porosity and permeability 30-40%, km depth Alba Field (Eocene Outer Moray Firth) Balder Field (Paleocene Utsira High) Briedis et al. 2007: AAPG Mem 87 Duranti et al. 2002: Pet Geosci

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6 Analogues for crestal sand injectites in Californian outcrops: Santa Cruz (a, b), San Joaquin Valley (c, d)

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8 Eocene Alba Field (Grid sst): 1B bbl field discovered by mistake..

9 Wing-producers doubled production on Gryphon (UK 9/18b) Jackson et al. 2011: AAPG Bulletin Production data courtesy of Maersk Oil UK

10 Seismic stratigraphic recognition of depositional, remobilised and fully injected sandstones Depositional sandstone (no remobilisation) Remobilised sand (in situ) 100% injected sand (saucer-shaped injectites) Mound (turbidite or extrudite) Remobilised mound Laccolith and marginal dykes (+ extrudite) Channel fill (truncation, onlap fill) Remobilised channel fill Conical injectite Huuse et al. 2012: EAGE

11 Submarine fans, lobes etc, in a sequence stratigraphic framework - are they all primary depositional sandstones? Den Hartog Jager et al 1993: PGC4

12 Paleocene sand injectites: NCS 35/11 (NE North Sea) Dmitrieva et al. 2012: Petroleum Geoscience

13 North Viking Graben injectites, extrudites and mudstone diagenesis Huuse 2008: WorldOil

14 Structural-stratigraphic setting of large-scale sand injectites in the South Viking Graben & Utsira High

15 South Viking Graben: sand injectite heaven 3D visualizations of injected sands reservoirs: South Viking Graben

16 Isolated massive sandstone mounds in the South Viking Graben: Balder (earliest Eocene) thickness and TWT structure

17 Gamma Volund: Early and Middle Eocene episodes

18 Wing-like reflections emanate from massive Balder-age sandstone on a scale similar to Alba and other remobilized fields (>200 m vertical) Total sandstone volume ~ 2.5 km 3 (all injected) 24/9-3 24/9-4 View looking North

19 Volund Field: Balder sand with marginal wings Discordant wings Frigg Balder Jack up Regional Top Balder OWC Sele

20 Volund: 3D morphology

21 Chestnut / Alba fairway: mid and Late Eocene episodes

22 Outer Moray Firth: sand injectite reservoirs, migration paths and drilling hazards Huuse et al. 2005: Petroleum Geology Conference

23 Sand injectites as reservoirs or conduits is not a new concept! AAPG Bulletin 1930:

24 UKCS Q22: lower Eocene (Caran) sst intrusions: Migration paths Thief sands Reservoirs Murphy & Wood 2011

25 Ringkøbing-Fyn High Oligocene: a spitting image of Mariner (Paleocene, East Shetland Platform) Andresen & Clausen 2014: Basin Research

26 BCU depth map with selected sand injectite field locations And overall injectite province outline 35/3,6,9, 36/1,4,7: Jackson et al Loseth et al /11: Dmitrieva et al /11: Mariner 24/9-7: Volund 15/30: Alba 22/2: Chestnut 28/9: Catcher 29/6: Danica Modified from Fraser et al (Millennium Atlas)

27 Kimmeridge Clay oil & gas expulsion vs sand injectite locations Modified from Kumala et al Millennium Atlas

28 North Sea overpressure (Jurassic, Cenozoic) vs Sand Injection Province: mutually exclusive Overpressure in the North Sea (modified from Kumala et al Mill Atlas)

29 Central Graben transect, overpressure and main injectite locations. Modified from Moss et al Millennium Atlas Cretaceous Late Paleocene/ Early Eocene mid Eocene Late Eocene/Early Oligocene Oligocene mid/late Miocene

30 SUMMARY.. At least 7 sand injection events in the North Sea 8-10 Myr interval some m of sedimentation between each episode Mutually exclusive relationship between SI and present-day overpressures (long term conduits!) Only a handful of exploration wells targeting injectites wells targeting injectites are aiming at thick wings updip of proven oil within jack-up/differential compaction anticlines Most larger fields located along basin margins charge control Origin of North Sea injectites still poorly understood Likely multiple causes Current work focused on regional 3D stratigraphic framework & detailed characterization and modelling (IS Phase 3 JIP)

31 Silica diagenesis and sand injectites: Viking Graben, Faroe-Shetland and Møre Basins Davies et al. 2006: Geology

32 Ormen Lange Miocene above opal A/CT Huuse et al. 2014: EAGE Conference Abstracts

33 Faroe-Shetland Basin (NE Atlantic): Conical intrusions below and 1km above Eocene fan

34 Barents Sea: middle Eocene sand injectites (Safronova PhD 2013)

35 E&P implications of sand injectition Unconventional sandstone occurrence Unconventional reservoir geometry Excellent reservoir properties (30-40% ϕ, 1-10 D) Long-term conduits for fluid flow - Migration paths, thief sands, connectivity Drilling hazards.. mads.huuse@manchester.ac.uk