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Basin and Petroleum System Modeling of Offshore Hawke Bay, East Coast Basin, NZ

Blair Burgreen and Stephan Graham

3rd Annual Stanford University Basin and Petroleum System Modeling Industrial Affiliates Meeting

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Allow me to introduce myself…

Blair Burgreen 2nd year PhD Student Advisor: Steve Graham

Research Groups: •  Basin and Petroleum System Modeling •  Stanford Project on Deep-Water

Depositional Systems

Research Interests: Basin and petroleum system modeling,

stratigraphic architecture, and detrital zircon provenance studies

Prior to Stanford: Consultant at A.T. Kearney B.A. from Dartmouth College

Zion National Park

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Forearc basins can be highly petroliferous given the proper circumstances

(Dickinson and Seely, 1979) (Hosford Scheirer and Magoon, 2008)

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Both positive and negative factors are commonly associated petroleum systems in forearc basins

Potential Benefits Typical Problems •  Plentiful structural traps: Active

tectonism creates numerous large scale structural traps

•  Plentiful stratigraphic traps: Depositional environments typically include shoreline, deltaic, and deep-water fans

•  High sedimentation rate: Detritus from the arc provides plentiful sediment for reservoirs and overburden

•  Poor reservoir quality: sands are often clay-rich due to diagenesis of volcanic source

•  Immature source rock: depressed geotherms

•  Discontinuity of reservoirs: development of the accretionary wedge causes faulting and shifting of depocenters

(Dickinson and Seely, 1979)

The East Coast Basin of the North Island is a modern forearc setting that initiated in the Early Miocene

(Uruski et al., 2006)

•  Jurassic-Cretaceous: subduction margin of Gondwana

•  Late Cretaceous – Oligocene: Rift to passive margin

•  Early Miocene – present day: forearc setting

•  Onshore/offshore basin

•  ~100,000 km2

Hawke Bay

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Gas and oil seeps throughout the onshore basin provide evidence for at least two mature source rocks

(Francis et al., 2004)

•  Numerous gas and oil seeps

•  Predominantly methane gas

•  Probable mature source rocks: 1.  Waipawa

o  Late Paleocene o  2-60 m thickness o  TOC = 1-12.3% o  Mean HI = 245 mg

HC/g TOC (max 550) 2.  Whangai

o  Late Cretaceous to Late Paleocene

o  400 m avg. thickness o  Mean TOC = 0.56% o  Mean HI = 159 mg

HC/g TOC (max 219)

•  Possible pre-Whangai Cretaceous source rock

Hawke Bay

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The forearc basin is comprised of numerous elongate sub-basins that shallowed and shifted arcward through time

•  Imbricate thrusts build up accretionary wedge

• Complex structure • Fill and spill deposition

• Many elongate sub-basins in forearc

• Highly localized stratigraphy

(Bailleul et al., 2007)

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The East Coast Basin contains all necessary ingredients of an active petroleum system

(Francis et al.,2004)

Possible Reservoir and Seal

Possible Source Rock

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This study will address several key topics with regard to the basin and petroleum system in Hawke Bay

•  Influence of depositional style on burial history •  Potential uplift and erosion scenarios •  Impact of thrust faulting on burial and timing of maturation •  Possible migration pathways given source rock maturation scenarios •  Refinement of possible gas sources through improved

characterization of source rock properties

(Christianson, 2008)

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Previous studies will be primary resources for development of the basin and petroleum system model

•  Hollis, C.J. and Manzano-Kareah, K. (compilers) 2005. Source rock potential of the East Coast Basin (central and northern regions). Institute of Geological and Nuclear Sciences Client Report 2005/118: 156 pp

•  Nicol, A. and Uruski, C.I. 2005: Structural interpretation and cross-section balancing, East Coast Basin, New Zealand. Institute of Geological and Nuclear Sciences Client Report 2005/118.

•  Funnell, R. and Benchilla, I. 2005. 1D Basin Models in the East Coast Basin, New Zealand. Institute of Geological and Nuclear Sciences Client Report 2005/120

•  Field, B.D.; Uruski, C.I.; and others. 1997: Cretaceous-Cenozoic geology and petroleum systems of the East Coast region, New Zealand. Institute of Geological and Nuclear Sciences Monograph 19: 2v., 301 p., 7 encl.

•  Field, B.; Higgs, K.; Pollock, R.; Jones, C.; Beuth, K. and Arnot, M. 2005. Reservoir Potential of the East Coast Basin (central and northern regions). Institute of Geological and Nuclear Sciences Client Report 2005/119: 152 pp.

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Prior 1-D modeling of pseudo-wells across a seismic line through Hawke Bay provides a starting point for this study

(Funnell and Benchilla, 2005)

Model Inputs

•  Waipawa: TOC = 4%; HI = 350; thick. = 25m •  Whangai: TOC = 1%; HI = 300; thick. = 400m •  Pre-Whangai: TOC = 1%; HI = 100; thick. = 1500m •  Pepper and Corvi (1995) kinetics for type II and III •  Reservoirs becoming less sand-rich to the east •  2 heat flow scenarios for high and low extremes •  Temperature and VR calibration from Hawke Bay-1

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The 1-D models use high and low heat flow input to examine scenarios for source rock maturation

(Funnell and Benchilla, 2005)

Heat Flow Scenarios • High heat flow – rifting scenario with max

heat flow at 83 ma; subduction at 23 ma • Low heat flow – passive margin scenario

until subduction at 23 ma

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Cumulative generation diagrams show that only the Cretaceous source rock is post-mature and expelled gas

(Funnell and Benchilla, 2005)

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Due to limited data in the East Coast Basin, key assumptions are inherent in the study

•  Source rock properties including TOC, HI, and thickness are estimated from highly variable and limited outcrop and well data

•  While the pre-Whangai Cretaceous source rock may have generated methane gas, there may also be a biogenic source associated with shallow burial

•  Generalization of lithologies based on limited well control and on-shore geology

•  Use of a seismic data set as model input relies on: 1.  Proper time-depth conversions to determine stratigraphic thickness 2.  Valid interpretations of depositional boundaries 3.  Limited well control does not reach source rock

•  Assumptions regarding heat flow based on tectonic histories

(Funnell and Benchilla, 2005)

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Initial 1-D modeling indicates vitrinite reflectance is underestimated

Temperature gradients indicate that vitrinite reflectance should be lower

•  Possible reasons: 1.  Uplift and erosion 2.  Advective heat flow 3.  Recycled vitrinite 4.  Erroneous data or kinetics

Future plans involve further structural reconstruction and 2-D modeling of an NW-SE transect through Hawke Bay

(Nicol and Uruski, 2005)

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TecLink will be used for the restoration to better understand the influences of imbricate thrusting on heat flow and burial history

(modified from Nicol and Uruski, 2005)

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The aim of this study is to answer fundamental questions and uncertainties with regard to the basin and petroleum system

1.  How does the prograding depositional style of turbidites impact burial histories?

2.  How does the timing and amount of thrust faulting affect source rock maturity and heat flow?

3.  Has there been more uplift and erosion than currently modeled?

4.  What does mature source rock distribution imply about potential migration pathways and trap timing?

5.  Is it possible to better map the source rock thickness and extent with the seismic data set?

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The research plan involves building several 1-D models and then integrating into the 2-D TecLink model

Update biostratigraphy for

well control

Create source rock maps for richness

and quality

Map source rock using seismic (if

possible)

Reinterpret/confirm seismic data

Build 1-D modeling for Hawke Bay-1 and for

pseudo wells

Create additional steps in palinspastic

reconstruction

Decide on blocks for TecLink model

Build 2-D TecLink Model

Test possible heat flow scenarios including advective heat, depositional scenarios, possible timings of faults, and impact of thrusting

(Field et al., 1997)

• Exposed around Tolaga Bay • Cliffs ~200 m high • Sub-basin fill in forearc • Analog for potential turbidite

reservoirs

Other research includes a stratigraphic architecture study of the late Miocene deep-water Hikuwai Sandstone

The cliffs along Tolaga Bay South provide excellent exposures for architectural analysis

E W

~300 m

~300 m Tolaga Bay Wharf

1 2 3

1

2

3

E

W

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A detrital zircon study is also underway to assess sandstone provenance throughout the Miocene

(Francis et al.,2004) zircon sample

Acknowledgements

Special thanks to:

Rob Funnell, GNS Science Chris Uruski, GNS Science Martin Crundwell, GNS Science Brad Field, GNS Science

Allegra Hosford Scheirer Ken Peters Oliver Schenk Carolyn Lampe And the rest of the BPSM

Research Group!

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References

Bailleul, J., Robin, C., Chanier, F., Guillocheau, F., Field, B., and Ferriere, J., 2007, Turbidite systems in the inner fore-arc domain of the Hikurangi convergent margin (New Zealand); new constraints on the development of trench-slope basins: Journal of Sedimentary Research, v. 77, p. 263-283, doi: 10.2110/jsr.2007.028.

Christianson, Lin (Pogo New Zealand), 2008, Final Interpretation Report for PEP 38344: East Coast Basin, NZ: Ministry of Economic Development New Zealand Unpublished Petroleum Report, Report PR3931, 1-120 p.

Dickinson, W.R., and Seely, D.R., 1979, Structure and stratigraphy of forearc regions: AAPG Bulletin, v. 63, p. 2-31, doi: 10.1306/ C1EA55AD-16C9-11D7-8645000102C1865D.

Field, B.D., Higgs, K.H., Pollock, R., Jones, C., Beuth, K., and Arnot, M., 2005, Reservoir potential of the East Coast Basin (central and northern subregions): Ministry of Economic Development New Zealand Unpublished Petroleum Report, PR3180,1-154 p.

Field, B., Uruski, C., Beu, A., Browne, G., Crampton, J., Funnell, R., Killops, S., Laird, M., Mazengarb, C., Morgans, H., Rait, G., Smale, D., and Strong, P., 1997, Cretaceous-Cenezoic Geology and Petroleum Systems of the East Coast Region, New Zealand: Lower Hutt, New Zealand, Institute of Geological & Nuclear Sciences Limited, p. 301.

Francis, D., Bennett, D., Courteney, S., and New Zealand, Crown Minerals, Wellington, (NZL), 2004, Advances in understanding of onshore East Coast Basin structure, stratigraphic thickness and hydrocarbon generation; New Zealand's petroleum basins, in New Zealand petroleum conference, Auckland, New Zealand: New Zealand (NZL), Crown Minerals, Ministry of Economic Development, Wellington, New Zealand (NZL).

Funnell, R., and Benchilla, I., 2005, 1D Basin Models in the East Coast Basin, New Zealand: Ministry of Economic Development New Zealand Unpublished Petroleum Report, Report PR3183, 1-24 p.

Hollis, C.J., and Manzano-Kareah, K., 2005, Source rock potential of the East Coast Basin (central and northern regions): Ministry of Economic Development New Zealand Unpublished Petroleum Report, Report PR3170, 1-158 p.

Hosford Scheirer, A., and Magoon, L.B., 2005, Age, Distribution, and Stratigraphic Relationship of Rock Units in the San Joaquin Basin Province, California, in Hosford Scheirer, A., ed., Petroleum Systems and Geologic Assessment of Oil and Gas in the San Joaquin Basin Province, California: U.S. Geological Survey Professional Paper 1713: [http:// pubs.usgs.gov/pp/pp1713/], U.S. Geological Survey, p. 1-107.

Nicol, A., and Uruski, C., 2005, Structural Interpretation and Cross Section Balancing, East Coast Basin, New Zealand: Ministry of Economic Development New Zealand Unpublished Petroleum Report, Report PR3184, 1-14 p.

Uruski, C.I., Field, B.D., Funnell, R., Hollis, C., Nicol, A., and Maslen, G., 2006, Developments in the central and northeastern East Coast Basin, North Island, New Zealand; 2006 APPEA conference: APPEA Journal, v. 46, p. 215-235.

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Questions?

Cook’s Cove, North Island, New Zealand