RECENT ADVANCES IN UNDERSTANDING TARANAKIPETROLEUM SYSTEMS: THE KUPE - MANAIA FAIRWAY

KF Kroeger, R Funnell, M Fohrmann, M Hill

Undiff. Mid-Late Cretaceous

Rakopi Fm

North Cape Fm

Farewell Fm

Otaraoa Fm

Murihiku/Brook Street Basement

Otaraoa Fm

Taimana Fm

Manganui Fm

Manganui Fm

Median Batholith

Otunui FmOtunui Fm

Mangaoapa Mbr Mangaoapa Mbr

Matemateaonga FmMatemateaonga FmTangahoe FmTangahoe Fm

Whenuakura FmWhenuakura Fm

0Kupe South-3Kupe South-2

A A’

1

2

3

4

5

6

7

8

9

10

Dep

th (

km

)

Fluvial

Facies/lithology units

Coal measures

Shoreface/shallow marine

Shelf

Coastal plain

Outer shelf/slope

Bathyal

Bathyal (marly)

Submarine fan

Submarine channel

Volcaniclastics

Undiff. Mid-Late Cretaceous

Rakopi Fm

North Cape Fm

Farewell Fm

Murihiku/Brook Street Basement

Otaraoa Fm Taimana FmManganui Fm

Otunui FmMangaoapa Mbr

Matemateaonga Fm

Tangahoe FmWhenuakura Fm0

Kapuni-13 Kapuni-8B B’

1

2

3

4

5

6

7

8

9

10

De

pth

(km

)

11

A

IntroductionThe remapping of the Taranaki Basin as part of the 4DTaranaki project at high resolution has produced a wealth ofnew data. Digital integration of well data, sequencestratigraphy, paleogeography and structural interpretationhas improved our understanding of basin architecture andevolution. These data have been used to build a highresolution 3D PetroMod™ petroleum systems modelintended to shed light on charge of traps and preservation ofpetroleum accumulations in the basin.

Forward modelling of the basin structure

Detailed reconstruction of the basin architecture and evolution throughtime has led to a new interpretation of carrier bed geometry. Theevolution of the southeastern Taranaki Basin was characterized byinitial submergence along with the formation of the convergent platebounday in the east, followed by Late Miocene inversion, renewedsubsidence and uplift of the Taranaki Peninsula. This evolution shapedthe structure along the crest of tha Manaia anticline, influenced closure,for instance at the Toru-1 well location, and controlled migration alongthe N-S fairway.

Thermal Model

To reproduce petroleum generation history, the3D thermal evolution of the area was modelled,using

Regional heat flow history (Kroeger et al. 2013)

Well data (temperature and vitrinitereflectance) for calibration

Standard organofacies Type III DE kinetics

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Seismic interpretation and grids fromFohrmann et al. (2012)

12

3

4

The 3D model consists of 15 layers interpreted from seismicdata (Fohrmann et al. 2012) and has been further subdividedto represent facies zonations of Strogen (2011).Images show lithological architecture along east-west (A-A’)and north-south (B-B’) transects through the model.

A B CRakop Formation Farewell Formation Mangahewa Formation

Above figures show the evolution of the crest of the Manaia Anticline(”Manaia Fairway”) from mid Miocene to Recent time along a N-S transect

N N N

0 Ma

6.5 Ma

8.5 Ma

16 Ma

S N

Above figure shows predicted petroleum generation (tons/m )l of A) Rakopi, B) Farewell, and C) Mangahewa Formation between Manaia and Taranaki faults. In addition, A shows modelled faults, B showsmain migration pathways and predicted accumulations as well as contribution of source rocks to Kupe accumulation.

2

within Farewell Formation

Age (Ma)100 0

Petroleum generation and migrationmodellingPetroleum systems modelling of the areahas provided greater detail on the timing ofsource rock maturation and factorscontrolling petroleum migration. Comparedto previously published data (i.e., TaranakiAtlas), a revised velocity model has led to anew interpretation of burial depth of sourcerocks. Deeper burial and therefore highermaturity could partly explain the gasproneness of this part of the basin.Migration was controlled by the changinggeometry of the Manaia Anticline andfaulting of the carrier beds and reservoirs.Later stage faulting affected seal integrity.

Results and Conclusions

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Farewell Formation is predicted to be the most important sourcerock in the Kupe region. This is consistent with geochemical data(Sykes et al. 2012)

Mangahewa Formation has the potential for generating petroleumin the onshore but little charge to the south is predicted

Gas-proneness of the Kupe Field is explained by main charge frommature source rocks in Farewell Formation north of the Toru-1 wellwith additional recent charge from Farewell coal seams proximalto the field

The geometry of the Manaia Fairway and trap closure is controlledby the history of burial and basin inversion

References

Fohrmann, M., Hill, M., Reid, E., King, P.R., Zhu, H., Roncaglia, L., Bland, K.J., Strogen, D.P., Scott, G.P.L., 2012. Seismic reflectioncharacter, mapping and tectono-stratigraphic history of the Kupe area (4D Taranaki Project), south-eastern Taranaki Basin, GNS ScienceReport 2012/36. GNS Science, Lower Hutt. 62pp

Kroeger, K.F., Funnell, R.H., Nicol, A., Fohrmann, M., Bland, K.J., King, P.R., 2013. 3D crustal-scale heat-flow regimes at a developing activemargin (Taranaki Basin, New Zealand). Tectonophysics 591, 175-193.

Strogen, D.P., 2011. Updated paleogeographic maps for the Taranaki Basin and surrounds, GNS Science Report 2010/53, Lower Hutt, 83pp.

Sykes, R.; Zink, K.-G.; Rogers, K.M.; Phillips, A.; Ventura, G.T. 2012. New and updated geochemical databases for New Zealand petroleumsamples, with assessments of genetic oil families, source age, facies and maturity. GNS Science Consultancy Report 2012/37, 29pp

Acknowlegements

This research was undertaken with Crown funding provided through the NewZealand Ministry of Business, Innovation and Employment (MBIE). Data usedfor high- resolution modelling were developed as part of the 4D Taranakiproject and we thank all GNS staff involved. We also thank Schlumberger foraccess to PetroMod™ software.

Kapuni-13

Kapuni-8

Tahi-1

Toru-1

Water Depth0 100 200 300 400 500

16 km

Taranaki Peninsula

Kupe South-1

Kupe South-2

Kupe South-3Kupe South-4

Kupe South-5

Kupe-1A A’

B

B’

1D thermal history at Kupe-1 well site extracted from the 3D model showing:(1) passive margin evolution and initial burial of the Taranaki Basin (2)convergent margin evolution and cooling due to crustal thickening (3) LateMiocene uplift and erosion (4) Pliocene-Recent burial stage most relevant forpetroleum formation.

Pliocene-Recent

Miocene

Eocene-OligocenePaleocene

Cretaceous

Manaia Fault

Manaia Anticline

(TOC = 3 mg/g) (TOC= 3-8 mg/g) (TOC = 3.5 mg/g)

Manaia Fairway

Predicted PetroleumComposition

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