The Hydrocarbon Case for the Orange River Basin

Neil Hodgson09/01/13

OrangeBasin

Post and Pre Salt plays are proven from Kwanza, Congo and Santos, Campos basins northward.

Whilst basins to the south are Salt free.

Q. Are all the plays in South Atlantic dependent on the presence of salt?

Q.  So are there any sources,reservoirs or structures in theOrange Basin? 

Walvis ridge

Q. Why do we need to establish the Hydrocarbon case for the Orange River Basin?

• Existing projects:

• Namcor Brokered data – 11,000km

• Veritas acquired data – 11,000km

• TGS Walvis JV data – 13,000km

• 2012 data – 16,000 km new data:• Orange Basin survey 50/50

ownership 8,165 km, • Luderitz Basin survey - 5,300 km• North Luderitz – 1,000 km acquired• AMIS S Walvis acquired –1,500 km

• Existing MC2D data test reprocessing• Phase 1 – 3 lines complete• Phase 2 - approx 4,000km

underway

Study Dataset

Basins with Source, Reservoir and Structure…

Yet only16 wells

7 into Kudu

500,000 km2

Hydrocarbon Play proven in the Barremian to Hauterivian in the 1.5 TCF Kudu gas field

Kabeljou Well (Petrobras/BP/Chariot) found Mature source

Oil Discoveries in Orange BasinIn South Africa

Orange River Basin

300km line

Post Rift

Pre Rift

Syn Rift

W E

Orange Basin Seismic

Hinge Rift Graben

Outer High

BUU

SDRs

Geological significance of gravity variations

Free air gravity

Hinge zone= reduced sedimentthickness

Break-Up-Unconformity (BUU)

Syn-Rift

Syn‐Rift Play

Syn Rift: Neocomian to Hauterivian Source Rock (Bucomazi Fm equiv)

Inboard Play system: Oil prone, extends up the margin, proven in Orange River Basin.

Pre BUU plays

SDR PlayOut-board SDR play

“Kudu” Barremian Aolian sst interbedded with Flood basalts

Pre BUU plays

BUU

Namibia: PSTM stack section.W E

200km

Structure : Depth ConversionPre BUU plays

Namibia: PSDM stack section. (Depth)

Structure : Depth Conversion

BUU

Outboard High

SDRs in 4-way dip closed structures; frequent along the margin

Pre BUU plays

Seaward Dipping Reflectors:  Reservoir‐Source system

Pre BUU plays

140‐120 ma The South Atlantic: Hauterivian to Early Aptian

Extent of Aptian Depositional Evaporite Facies

(after Borsato et. al. 2012)

Orange

Ezanga, Loeme Salts

Pre BUU plays

Syn Rift Grabens – depositing lacustrine source rocks ( East African Rift Analogue)

Ariri, Alagoas Salts

Extent of Aptian Depositional Evaporite Facies

(after Borsato et. al. 2012)

Orange

Pre BUU plays

Late Aptian Syn‐rift – LIP Volcanism producing flood basalts of the SDR Phase.

Transition from SDR to MORB type Ocean Floor Basalt 

“Transitional” Crust: Peneplaned marine transgressionMORB ocean floor basalt

Out-board high

Subsidence

MarineTransgression

Pre BUU plays

SDR Namibia

SDR Uruguay

Ca 120 ma

Pre BUU plays

110 ma The South Atlantic: Albian 

110ma

Post BUU plays

USGS 2006 after Tissot 1980

USGS 2006 after Tissot 1980

Wells Demonstrate Cenomanian-Turonian Source Rocks

Kabeljou Well (Petrobras/BP/Chariot) reportedly found Mature Cenomanian/ Turonian source

Basin Modelling initial results

K/T Boundary

Break up uncon

SP15000 SP7000 SP1500

Post BUU plays

MaturityPost BUU plays

Orange/Sanqu Watershed

Post BUU ReservoirPost BUU plays

1: Syn Rift sequence:Inboard High Out Board HighHalf Graben trapsSDR traps

2: Post Rift sequence: Onlaps to Out Board HighDrape over Out Board High

3: Deltaic sedimentalogical Plays:Deepwater fansChannels

4: Deltaic Gravity playsTilted Fault BlocksSlumpsSlumps strat targets

Traps and plays

Conclusion

Cretaceous Deltaics: Gravity Plays

Conclusion

Cretaceous Deltaics: Slope Channels

Conclusion

Deep water Pinchout Play

Aptian Half GrabenOil Mature

Out-board high

Conclusion

Conclusion

• Exciting area Very underexplored

• Source, Reservoir and structures, present in Pre-Break up Unconformity sequence

• Several Sources, Reservoir and structures, present in Post-Break up Unconformity sequence

• Large database of existing and new data

• The Presence of salt is not required for valid exploration plays on this margin.