25th International Meeting on Organic Geochemistry IMOG 2011

P-314
Chemometric analysis of oil-oil and oil-source rock correlations
in New Zealand basins
Richard Sykes, Klaus-Gerhard Zink
GNS Science, Lower Hutt, New Zealand (corresponding author:r.sykes@gns.cri.nz)
This paper presents a chemometric-based study of
oil-oil and oil-source rock correlations in Taranaki and
other New Zealand basins. Using Hierarchical Cluster
and Principal Component Analysis and a preferred set
of 14 source-related biomarker and carbon isotope
parameters, correlations are established between 134
oils and gas condensates and 95 source rocks of
known age and organofacies. The selected biomarker
parameters provide effective characterisation of the
angiosperm, gymnosperm, total higher plant, and
marine organic matter inputs to the respective source
rocks. Moreover, the parameters are not unduly
affected by source rock maturity, low–moderate
biodegradation (up to level 3–4) or petroleum phase
fractionation, and thus appear to provide generally
robust correlations of the oils and gas condensates.
The correlations herein refine and expand previous
identifications of oil families and provide improved
characterisation of source rocks. Five oil (and gas
condensate) tribes and 13 families are identified:
Tribe 1: Late Cretaceous, terrestrial source rocks
with high gymnosperm inputs:
� Family 11: Offshore Taranaki (Tui and Maui
fields, Taranui-1, Maui-4) and Grey Valley Basin
(Niagara-1)
� Family 12: Offshore Taranaki (Pukeko-1) and
Grey Valley Basin (Petroleum Creek-3 and
Kotuku, Mt Davy Mine and Spark & Party Mine
seeps)
� Family 13: Offshore Taranaki (Maari Field)
Tribe 2: Paleocene–Eocene, terrestrial source rocks,
intermediate gymnosperm and angiosperm inputs:
� Family 21: On- and offshore Taranaki, Manaia
Trend area (Kupe and Kapuni fields, Toru-1)
� Family 22: Onshore Taranaki Peninsula (Ngatoro
and Goldie fields)
Tribe 3: Eocene, terrestrial source rocks with high
angiosperm inputs:
� Family 31: Onshore Taranaki Peninsula,
southern Tarata Thrust area (Waihapa, Ngaere,
Cardiff, Stratford, Ahuroa, Cheal and Wingrove
fields, Huinga-1B, Rimu-B1, Kauri-A2 and -F1)
� Family 32: Onshore Taranaki Peninsula, northern
Tarata Thrust area (McKee, Tariki, Kahili and
Mangahewa (Zone B) fields)
� Family 33: On- and offshore northern Taranaki
Peninsula (Moturoa, Pohokura and Mangahewa
fields, Pukearuhe-1) and Waihapa-1A.
Tribe 4: Late Cretaceous–Eocene, marine and
coastal facies source rocks with relatively high marine
organic matter inputs:
� Family 41: Offshore northern Taranaki (Pluto-1)
� Family 42: Offshore northern Taranaki (Kora
Field)
� Family 43: Onshore northern and southern East
Coast Basin (Rotokautuku, Totangi, Waitangi,
Isolation Creek and Kaikoura seeps)
Tribe 5: Jurassic–mid Cretaceous?, terrestrial source
rocks characterised by relatively low total higher plant
input:
� Family 51: On- and offshore southern Taranaki
(Rimu and Kauri fields), offshore northern
Taranaki (Te Ranga-1)
� Family 52: On- and offshore southern Taranaki
(Kauri Field)
Oil families within the essentially terrestrial-sourced
tribes (1–3, 5) are distinguished primarily by variations
in the levels of synsedimentary marine influence,
anoxicity and/or angiosperm input within the coalbearing
sequences of the respective kitchen areas.
Within Taranaki Basin, the oil family groupings tend to
be geographically constrained and help to identify
source kitchens and migration pathways. The Kupe
and Kapuni fluids, for example, cannot be
distinguished by field, strongly suggesting derivation
from a common source kitchen.
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