Northwest Africa Atlantic Margin MSGBC Basin Prospectivity. Ben Sayers Project Developer Africa, Mediterranean & Middle East 27 th May 2015

Transcription

1 Northwest Africa Atlantic Margin MSGBC Basin Prospectivity Ben Sayers Project Developer Africa, Mediterranean & Middle East 27 th May 2015

2 Legal notices By viewing this document made available to you by TGS-NOPEC Geophysical Company ASA ( TGS ), you hereby acknowledge and agree that: (i) TGS owns all copyrights for the document; (ii) TGS is providing you with access to the document, provided that you do not distribute, in any medium, to a third party without TGS s prior written consent; and (iii) you are viewing the document solely for your internal use. The images in this document shall not be scanned or loaded to any PC/workstation that makes the data image capable for manipulation or transformation back into commercially viable information. 2

3 Contents Introduction Geological Evolution of the MSGBC Basin Exploration History NWAAM Survey Location and Acquisition Play concepts and thermal modelling Data Examples Summary Conclusions Guinea Conakry Guinea Bissau AGC Senegal/The Gambia Mauritania 3

4 Geological Evolution of the MSGBC Basin 4 4

5 5 Mauritania, Senegal, Gambia, Bissau, Conakry (MSGBC) Basin

6 Basin Evolution The pre-rift section is made up of: Palaeozoic extensional tectonics in the south with horsts, grabens and tilted fault blocks preserved from Pre-Hercynian; and Compressional tectonics in the north and central parts of the basin with effects of Hercynian and Caledonian orogenies.

7 Basin Evolution Triassic Triassic The basin was formed at the end of the Permian in a Triassic ift system. Lacustrine source rocks were deposited followed by continental Triassic clastics 1500m thick.

8 Basin Evolution Triassic Early Jurassic Early Jurassic A thick sequence of Triassic/Early Jurassic evaporites were deposited in the basin. Up to 2000m of salt. Transgressing seas brought post-rift marine sediments.

9 Basin Evolution Triassic Early Jurassic Mid-Jurassic Mid-Jurassic m thick carbonates reservoirs were deposited form an active carbonate factory. The platform both prograded and regressed through time.

10 Basin Evolution Triassic Early Jurassic Mid-Jurassic Mid-Cretaceous Mid-Cretaceous Thick marine shales interbedded with marginal marine sandstones deposited after the opening of the Atlantic in the Cenomanian. Black, bituminous Turonian shales were deposited marking the maximum Cretaceous transgression

11 Basin Evolution Triassic Early Jurassic Mid-Jurassic Mid-Cretaceous Upper Cretaceous/Tertiary Senonian marine regression which culminated in deposition of thick Maastrichtian sandstones. Up to 1200m thick. Tertiary sediments are unconformable and consist of marine shales, carbonates with influx of sandy turbidites Upper Cretaceous/Tertiary

12 Basin Evolution Triassic The Basin has undergone a complex history that can be divided into 3 main stages of development: Early Jurassic the pre-rift (Precambrian to Paleozoic) syn-rift (Permian to Early Jurassic) Mid-Jurassic post-rift (Middle Jurassic onwards) Mid-Cretaceous Upper Cretaceous/Tertiary

13 Exploration History 13 13

14 Drilling Summary To date 177 exploration wells have been drilled in the basin with 115 encountering hydrocarbons 66%! Of the 110 offshore wells: only 60 are in water depth of greater than 100m; only 30 in water depths greater than 1000m; And only 2 in water depths greater than 2000m. 100 MMBOE SNE MMBOE Avg. sized Discovery FAN-1 Adapted from Grant et al Copyright SIEP BV. (Source FA website) 14

15 NWAAM Survey Acquired in collaboration with: 15 15

16 NWAAM Survey

17 NWAAM Survey NWAAM Phase 2 NWAAM Ph2 Acquisition May - November 2012 Covered Area 140,000 km 2 NWAAM Phase 1 NWAAM Ph1 Acquisition April October 2011 Covered Area 220,000 km 2

18 NWAAM Survey NWAAM Ph2 Streamer Length: 8km ecording Chs: 640 ecord Length: 14 sec (NWAAM Ph2) 9 sec (NWAAM Ph1) NWAAM Ph1 More info:

19 PE-IFT SYN- IFT EALY POST- IFT Cretaceous POST-IFT NWAAM egional Stratigraphy Maastrichtian Limestone reservoir Clastic reservoir Source rocks Cretaceous Tertiary ESEVOI Cenomanian Cenomanian / Turonian MAINE SOUCE OCK Albian ESEVOI Aptian MAINE SOUCE OCK Jurassic Triassic Triassic ESEVOI Triassic LACUSTINE SOUCE OCK? Devonian ESEVOI Silurian MAINE SOUCE OCK? M. Brownfield and. Charpentier, 2003

20 Play Concepts Miocene Sources Hypothetical: Shales deposited and Miocene reservoirs are proven so would just require sufficient burial Buried Hills POBABLE: Albian shelf eroded by Senonian unc., karstified, then sealed by upper Cretaceous to lower Tertiary shales & marls. Evident on Seismic Buried Hills Salt related Salt traps and structures are proven throughout the basin. Chinguetti Field etc Jurassic Carbonate eservoir POVEN: Offshore Cape Timiris-1, Loup de mer-1 Turonian/Cenomanian Sourced POVEN: Lots of wells including Jammah-1 GB-1, Sabu-1, Sheepshead-1 Aptian-Albian POVEN: FAN-1 and SNE-1 Triassic Hypothetical: Lacustrine sources charging Triassic clastics sub-salt. Works in Morocco and Newark basin Silurian Sourced Possible: Silurian present across majority of North Africa and Paleozoic sandstones (15-20% Ф) present in Bove Basin along with 400m thick Silurian Buba Shale source rock

21 NWAAM Data Play Examples 21 21

22 NWAAM - Mauritania Sub Basin Coppolani-1 Sea Bed Top Lower Miocene Senonian Unc. Top Turonian Top Aptian Top Neocomian Analogous to Top Sag Chinguetti field? Top Syn-ift Eocene-Oligocene Carbonates Sea Bed Salt-related sand deposition? Top Lower Miocene Analogous to Labeidna field? Coppolani-1 well was un-economical discovery. Syn-kinematic Oil found in the Maastrichtian, charged sand deposition? Type II Turonian oil. Lower Aptian- Neocomian updip brightening Senonian Unc. Top Turonian

23 NWAAM Southern Mauritania Sub Basin W Faucon-1 WD = 1164m TD= 4170m E Sea Bed Top Lower Miocene Senonian Unc. Top Turonian Top Aptian Top Neocomian Top Jurassic Salt diapir creates traps for updip migration Faucon-1 drilled HC bearing sandstones from the Lower Campanian Salt present throughout the majority of the basin.

24 NWAAM Sangomar Basin W Image credit: Cairn Capital Markets Day, 11 th May 2015 SNE-1 WD = 1100m TD= 3000m FAN-1 WD = 1427m TD= 4927m E Sea Bed Top Oligocene Top Senonian TWT (sec) Top Albian Top Jurassic Top Syn-ift 2 recent discoveries in the basin, both Albian sandstone reservoirs sourced from Aptian sources. FAN-1 is a set of stack fans SNE-1-96 metre oil column in 24% PHIE shelf edge sands FAN-1 & SNE-1 have a combined p-50 reserve estimate of over a Billion barrels of Oil of API 32

25 NWAAM Casamance Basin W SNE-1 analogue E FAN-1 analogue Sea Bed Top Oligocene Top Senonian Top Albian Top Aptian Top Jurassic Top Syn-ift Triassic source rocks? 8km Similar structuration to Sangomar basin despite being 150km further south SNE-1 analog further up-dip which has an AVO response showing stacked sands. Salt dome post-salt clastic play? Evidence of Pre-salt Triassic play

26 TWT (sec) NWAAM - Casamance Sub Basin (AGC) Sea Bed Cenomanian source interval HC related brightening? Fault bounded updip brightening Top Albian Top Aptian Top Jurassic Top Syn-ift Contractional structures and fault bounded brightening Salt tectonics have controlled sand deposition Amplitude anomalies in the Lower Albian related to HC charge or high porosity sands

27 NWAAM - Southern Sub Basin (Guinea Bissau) Sea Bed HDZ? Aptian channel sands with updip pinchout over flank of salt diapir Top Oligocene Top Senonian Albian-Aptian sands Top Albian Updip brightening or charged sands Top Aptian Salt dome Hydrocarbon elated Diagenetic Zones (HDZ) indicate a highly charged hydrocarbon system. Aptian-Albian sediments pinching out against the Jurassic carbonate platform and showing high amplitude anomaly. Aptian sand channels pinching out over the flank of salt.

28 TWT (sec) NWAAM - Southern Sub Basin (Guinea Bissau) S N Sub-crop unconformity traps Salt related structures Top Oligocene Top Senonian Top Albian Top Aptian Top Jurassic Top Syn-ift Syn-ift sands? Diapir piercing Late Cretaceous sediments. shallow water sub-crop unconformity traps at the edge of the hinge zone. syn-rift sands below the salt.

29 NWAAM - Offshore Guinea Conakry S Sea Bed N Top Oligocene Top Senonian Top Aptian Top Jurassic Top Syn-ift Early syn-rift Sediments TWT (sec) Pre-rift Sediments Thinner Mesozoic sediments due to basement geometry. Triassic source rocks in oil window Possible evidence of presence of Silurian sources and Devonian clastics

30 Northern Sierra Leone Sea Bed Top Cretaceous Top Aptian Top Miocene Base Neogene Top Eocene A series of Mid-Albian (syn-rift) fault terraces with some bright amplitudes within the fault blocks that relate to sand-prone sequences within the syn-rift sediments.

31 NWAAM Southern Mauritanian Sub Basin W E Tortue-1 WD = 2668m TD= 4630m 150m gross hydrocarbon bearing interval in the Upper Cenomanian 160m gross interval with 3 distinct MULTI-Darcy reservoirs in Lower Cenomanian Other plays deeper in the Cretaceous are also expected

32 NWAAM - Casamance Sub Basin (AGC) CM-7 W E Line Bend S Updip closures Faulted Blocks Albian slope fan sand channels Sea Bed Senonian Unc. Top Albian Top Aptian Top Jurassic Top Syn-rift

33 NWAAM - Northern Sub Basin (Offshore The Gambia) Sea Bed Senonian Unc. 1.8 seconds (TWT) Top Albian Top Aptian SNE-1 Analogue 3.7 seconds (TWT) Top Jurassic Top Syn-rift FAN-1 Analogue Syn-ift Sandstones?

34 NWAAM The Gambia 3D Lamia Albian Shelf Edge Mahogany Acacia Nema SNE-1 Analogue FAN-1 Analogue TGS also have a multi-client 3D survey offshore The Gambia, 2,500 sq. km acquired in km osewood Paprika Sami Albian-Santonian Deepwater play Alhamdulilah Image credit: Africa Petroleum Natural esources Forum, April 2015

35 Summary - Prospectivity There are three main petroleum systems present in the MSGBC basin: A post-rift sequence: Source - proven Aptian / Albian / Turonian; eservoirs - Upper Cretaceous / Tertiary clastic rocks and Jurassic carbonates; Seals - Upper Cretaceous/Tertiary marine shales or allochthonous salt. A pre-salt sequence: Source rocks - Triassic lacustrine; eservoirs - Triassic syn-rift clastic rocks and/or Jurassic early postrift limestones; Seals - interbedded shales or salt. A pre-rift Silurian/Devonian level: proven onshore and probably extending offshore in the shallow shelf area of Guinea Conakry.

36 Conclusions Basin and Sub-basin evolution and architecture is controlled by preexistent basement geometry, syn-rift faults, transform movements and salt tectonics. The complex structural evolution has led to the formation of numerous structural and stratigraphic traps identified across the study area. Potential DHIs such as bright spot and gas related features have been highlighted. The numerous discoveries in the Basin prove the existence of working petroleum systems along the North West African Passive Margin and FAN-1 and SNE-1 prove these systems can be commercial.

37 Acknowledgments TGS for Interpretation and modelling work: Dario Chisari, Peter Conn, Ian Deighton, oel Dirkx, Jennifer Halliday, Cian O eilly, and Erika Tiboucha. External references: African Petroleum (interpretation of TGS 3D) = df Last accessed 26th May 2015 Cairn Energy (FAN-1 and SNE-1 geoseismic and pressure curve data) = Last accesed 26th May 2015 FA Limited (3D Interpretation of SNE-1 and FAN-1) = Grant, C. et al Hunting for deepwater subtle traps, from Geology to Technology. The 5 th Biennial Petroleum Geology Conference. Bergen, Norway. March 2013.

38 Thank you Ben Sayers