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