3d inversion & negative inversional fault systems, taranaki basin, offshore nz

3D INVERSION & NEGATIVE INVERSIONAL FAULT SYSTEMS, TARANAKI BASIN, OFFSHORE NZ

Isaac Kenyon

Mt. Taranaki onshore New Zealand

GL5011: Petroleum Geoscience Independent Project

Royal Holloway Postgraduate Scholarship Recipient

Research Location Source: Modified from (King et.al., 2010) Study Regions

Dataset

Source: Modified from (King et.al., 2010) & (Energy-pedia.com, 2016)

Shell drilled the Maari

well

Maui Field (3.4 TCF)largest field in the

Taranaki Basin

Aims Of Research

1. Model the tectonostratigraphic evolution of the Taranaki Basin.

2. Identify precise locations inversion initiation on individual faults during the Eocene-Miocene compression.

3. Analyse tip line propogation of young Plio-Pleistocene extensional faults and their kinematic interaction between separate fault segments.

4. Discussion of negatively inverted rift faults and reactivated normal faults during the Pliocene and their implications on hydrocarbon migration.

(Mid-Late Cretaceous (100-66MA)

Intra-Continental Rifting

Rifting associated with Gondwana break up and spreading of the Tasman Sea.

Dominated by non-marine deposition close to NZ and deep water in the Taranaki Basin.

Source: Modified diagram from (King et al., 2010)

(Paleocene to Eocene (40Ma) Passive Margin

End of the Tasman Sea spreading (52Ma) during the Early to Middle Eocene developing tectonic quiescence and widespread marine transgression.

Middle Eocene to Oligocene, sees sea-floor spreading in the Emerald Basin

Source: Modified diagram from (King et al., 2010)

Mid Oligocene (27Ma)

Convergent Margin

Mid Eocene sees sea-floor spreading in the Emerald Basin develop.

Pacific Plate subduction under north-eastern New Zealand (27Ma).

Source: Modified diagram from (King et al., 2010)

Miocene To Present (10-0Ma)

Back-arc Extension & Trench Roll-back

Alpine Fault evolved, forming a link between west-dipping Hikurangi subduction, Emerald Basin spreading and oblique extension in the southwest.

Relative motion across this plate boundary is increasingly convergent throughout the Neogene.

Source: Modified diagrams from (King et al., 2010)

CHRONO-STRATIGRAPHIC

CHARTSource: modified from (King and Thrasher, 1996)

(King et.al., 2010)

Amplitude attribute

Regional 2-D Line

Fault & Fold Map Analysis

Horsts, grabens & growth

strata appear. Post rift

faults reactivated.

Early rifting faults negatively

Inverted. New

extensional faults develop.

Strike trend changing.

Large rift border faults.

Synthetic smaller

extensional faults. Large

depression develops between these.

General trend in NNE strike.

Faults begin to link up.

into larger master faults. Extensional

faults develop.oblique to major rift faults. Major rift

faults show inversion signature here (Harpoon shape).

New extensional faults develop again oblique to major rift faults (crestal collapse structures accommodating inversion perhaps).

Two clearly different strike trends.

Recent extensional faults reactivated.

Other rift faults negatively inverted.

Faults only active in the North of study area.

NE strike trend.

Basin Evolutionary Thickness Variations

A A’

Pre-Rift (Basement)CAP~115Ma

Regional Extensional

Direction perpendicular to antithetic

faults

Sand bodies in asymmetrical

half graben depocentres

EconomicDeep

Reservoirs

Curved faultwing tips, potentiallink up

3 7 8 8 10 11 11 160

2

46

Pre-Extension Fault Length (Km) Vs Throw

(km)

Fault Length (Km)

Thro

w (K

m)

Recent extension faults penetrating in the NE.

Rift faults link and increase in strike length.Regional Extensional

Direction perpendicular to antithetic faults

Syn-Extension 1 (CAL~110Ma)

Extraction shows the 3D arch of faults

2 3.5 5 6 9 140

100020003000400050006000

Syn-Extension 1 Fault Length (Km) Vs Throw (m)

Fault Length (Km)

Thro

w (

m)

Post RiftCS~85Ma

Trends:

Basement involvement

seismically active

Regional Extensional Direction perpendicular to

antithetic faults

NE-SW (accommodationfaulting)NNW-SSE(tend to beInverted)NNE-SSW

Maui-4 welltarget

1.8 2.5 2.8 3.5 4 4.3 4.5 6 8 10 190

100020003000400050006000

Post-Extension 1 Fault Length (Km) Vs Throw (m)

Fault Length (Km)

Thro

w (m

)

Post-Inversion (TO)~23Ma

85 65 500

1000

2000

3000

4000

5000

Late Cretaceous to Palaeocene Fault Growth Curve

Large in-verted (Kiwi Rift Fault)

Smaller Fault

Younger Structure

Age (Ma)

Cum

ulat

ive

Thro

w (

m)

Regional Compressional Direction perpendicular to

antithetic faults

Relay ramps

Linked en-echelonfaults

Segmented inversionof rift faults

Overlapping fault tips

B

B’

(B) (B’)

Hydrocarbon Trap Leakage

Post-Inversion Hydrocarbon Implications Gas leakage through chimneys, utilizing reactivated faults.

NS

22 7 0-100100300500700900

1100

Miocene to Plio-Pleistocene Fault Growth Curve

Large Ex-tensional NE Fault

Smaller Ex-tensional Faults not contributing much to re-cent exten-sion

Age (Ma)

Cum

ulat

ive

Thro

w (m

)

Post-Recent extension(CC)~7Ma

Lack of faults in the south

Negatively Inverted faults

Regional Compressional

Direction perpendicular to antithetic faults

Extension is NNW-SSE trending.

D

D’

Negative Inversion in the Plio-PleistoceneLocated in the North of the

3D dataset, lack of reactivation in the South.

Growth stratal sequences fairly recent in the Plio-Pleistocene.

Basement rift faults are fairly challenging to understand so reason for activation isn’t truly understood.

Tectono-Stratigraphic EvolutionPre-Rift (Basement)Pre Late Cretaceous

CAP~115Ma

Large rift border faults.Synthetic smaller extensional faults.Large depression develops

between these.General trend in NNE strike.

Tectono-Stratigraphic EvolutionFaults begin to link up.into larger master faults.

Extensional faults develop oblique to major rift faults.

Major source rock intervals are located in the HW of these faults.

Syn-Extension 1Late Cretaceous

CAL~110Ma

Tectono-Stratigraphic EvolutionPost-Extension 1Early Paleocene

CS~85Ma

New extensional faults develop again oblique to major rift faults (crestal collapse structures accommodating inversion perhaps).

Major marine transgression i.e. differential

compaction.

Prograding delta clinoforms develop towards the WNW.Two clearly different strike

trends.

Tectono-Stratigraphic EvolutionPost-InversionEarly Miocene

(TO)~23Ma

Syn-extensional up-dip growth strata.

Master rift faults reactivated during syn-inversion.

HW anticline and FW synclines.

Erosional unconformity develops.

New NE depocenter with many horsts and grabens.

Tectono-Stratigraphic EvolutionSyn-Extension 2Early Pliocene

(TM)~7Ma

Recent extensional faults reactivated.

Other rift faults negatively inverted.

Faults only active in the North of study area.

NE strike trend.

Tectono-Stratigraphic EvolutionPresent Day

(0Ma)Lack of extensional

activity (only 10% of faults active at this time), evidence in seismic.

No faults seen on this surface.

Migration Pathway & Traps Risk Analysis

Conclusions

• Sedimentary strata record four main periods of deformation;• Locations and orientations of various periods of faulting are

influenced by the locations and orientations of pre-existing faults; • Basement reactivation, inversion, fault propagation and recent

extension observed in the Maari survey;

• Plio-Pleistocene faults in the Maari Area form a relatively immature fault system i.e. long fault lengths achieved rapidly;

• Exploration targets comprise both structural and stratigraphic objectives, with high risk levels due to multiple phases of reactivation (inversion and recent extension) & seal effectiveness;

ACKNOWLEGEMENTSProfessor Ken McClay

Dr. Nicola Scarselli

Dr. Ian Watkinson

Geoscience New Zealand (GNS Science) – Maari survey dataset

Halliburton Landmark – Seismic Interpretation Software (DecisionSpace & Geoprobe)

THANK YOU FOR LISTENING!

IN ASSOCIATION WITH

Further Study

• Inversion of Late Cretaceous Rift Faults to understand the implications of structural style on New Zealand’s plate boundary settings;

• Investigation of Plio-Pleistocene fault kinematics and growth history within Maari 3-D survey;

• Implications of inversion and extension on the migration of hydrocarbons along faults;

EXTRA SLIDES

Exploration History

Source: Modified from (King et.al., 2010) & (Energy-pedia.com, 2016)

Structural Elements

Inverted rift faults from the Late Cretaceous in the blue area (South basin where my dataset is and also the Cape Egmont Fault Zone) with recent volcanics found in the North of the Taranaki Basin.

Western Platform is in yellow and is the stable deepwater region.

Source: Modified from (Muir et.al., 2000) & (Knox, 1982)

Regional Extensional

Direction perpendicular to antithetic faults

Pre-Extension (Basement)CAP~115Ma

Antithetic Fault

Faults generally dipping SE

Inverted rift faults

EconomicDeep

Reservoirs

Syn-Rift (CAL~110Ma)

Variance Time Slice

RMS (CAL) horizon Intersecting seismic variance slice

Post-Extension Transgression (CS~50Ma)

High amplitude chaotic reflectors. Channel basal surfaces. Prograding WNW

EconomicRegional Seal

Post-Recent extension(CC)~7Ma

22 7 0-100100300500700900

1100

Miocene to Plio-Pleistocene Fault Growth Curve

Large Ex-tensional NE Fault

Smaller Ex-tensional Faults not contributing much to re-cent exten-sion

Age (Ma)

Cum

ulat

ive

Thro

w (m

)

D

D’

Lack of faults in the south

Negatively Inverted faults

C C’

Fault Growth Curves

85 65 500

500100015002000250030003500400045005000

Late Cretaceous to Palaeocene Fault Growth Curve

Large in-verted (Kiwi Rift Fault)Smaller FaultYounger Struc-ture

Age (Ma)

Cum

ulat

ive

hrow

(m)

22 7 0-100

100

300

500

700

900

1100

Miocene to Plio-Pleistocene Fault Growth Curve

Large Exten-sional NE Fault

Smaller Exten-sional Faults not contribut-ing much to recent extension

Age (Ma)Cu

mul

ativ

e Th

row

(m)

Strike Dimension VS Fault Throw

1.9 3.5 6 6.5 3.8 4.8 6.5 7 6.60

200400600

Post Extension Fault Strike Dimension (Km) Vs Throw

(m)

Strike Dimension (Km)Th

row

(m)

16 12 9.5 4.2 8.5 2.7 11 9 6 6 70

50010001500

Syn-Inversion Fault Strike Dimension (Km) Vs Throw

(m)

Strike Dimension (Km)

Thro

w (m

)

2 3.5 5 6 9 140

200040006000

Syn-Extension 1 Fault Length (Km) Vs Throw

(m)

Fault Length (Km)Th

row

(m

)3 7 8 8 10 11 11 16

0

2

46

Pre-Extension Fault Length (Km) Vs Throw

(km)

Fault Length (Km)

Thro

w (K

m)

1.8 2.5 2.8 3.5 4 4.3 4.5 6 8 10 190

100020003000400050006000

Post-Extension 1 Fault Length (Km) Vs Throw (m)

Fault Length (Km)

Thro

w (m

)

Fault Orientation (Rose Diagram)

Evolution Model of Inversion

1 2 3 4

5

Gippsland Comparative Basin

Digital terrain image of the Gippsland

Basin displaying the major tectonic Elements. Source: (Ga.gov.au, 2016)

Gippsland Basin Regional Line

Petroleum Systems Chart