Hydrocarbon generation modeling and source rock characterization of the Cretaceous–Paleocene Taratu Formation, Great South Basin, New Zealand

Abstract

Hydrocarbon generation modeling and source rock characterization have been carried out on rock samples of the Taratu Formation in the Great South Basin, New Zealand. The Paleocene and Late Cretaceous Taratu Formation samples from Tara-1 well are utilized for geochemical studies. Rock-Eval pyrolysis results show that Taratu formation accommodates organic matter of excellent quantity and quality, with proliferous kerogen type II-III (oil and gas prone) and minor kerogen type III (gas prone). Hydrogen index (HI) of this formation ranges from 165.0 to 327.5 mg HC/g TOC and only Late Cretaceous source rock samples are thermally mature, with maximum pyrolysis temperature (T max ) up to 459 °C and vitrinite reflectance (% R o ) from 0.40 to 1.15% R o . One-dimensional basin modeling shows a best fit in a calibration of measured and modeled temperatures and vitrinite reflectance. The top of oil window was encountered 51 Ma ago at 3100 m and gas generation took place at 4132 m in 8 Ma ago.

Basin and petroleum system modeling in conjunction zone of the Alexander and Srednevasyugan anticlines and Ust-Tym depression, southeastern part of the West Siberian hydrocarbon province (Russia)

“…To represent the natural conditions in the basin, thermal modeling was carried out by reference to the vitrinite reflectance, present-day surface heat flow (Duchkov et al 2013), and present-day reservoir temperatures (Alipour et al 2019;Hantschel and Kauerauf 2009;Higley et al 2006;Makeen et al 2016b;Osli et al 2019). The heat flow calibration illustrated in Fig.…”

Massive seafloor mounds depict potential for seafloor mineral deposits in the Great South Basin (GSB) offshore New Zealand

“…More so, the mid-Cretaceous coaly sediments of the Hoiho Group have been documented as the most likely sources of gas condensate and oil shows encountered in the Kawau-1A wellbore 27 . Oil and gas shows are also recorded in the Tara–1, Toroa–1, and Pakaha–1 with minor methane detected in the Pukaki-1 well 27 , 38 . At the Paleocene level, the Taratu Formation in Tara-1 is characterized by very high percentages of degraded brown phytoclasts, rare marine algae, and amorphous organic matter portraying a mix of terrestrial and marine kerogen 29 .…”

“…The major intraplate volcanism in the GSB are dated Late Cretaceous, Palaeocene to Early Eocene, Late Eocene to Early Oligocene and Middle to Late Miocene 34 and are depicted by several buried volcanic features including the Late Cretaceous to Early Eocene (~ 85–45 Ma) Tuatara Volcanoes 32 , the Upper Eocene to Lower Oligocene (40–34 Ma) Waiareka–Deborah volcanoes 35 , the Early Miocene (16–11.7 Ma) Dunedin Volcano 35 and references therein, the Miocene (12–6 Ma) Akaroa and Lyttleton volcanoes 34 , 35 , the Oligocene to Early Miocene Papatowai volcanoes 36 and the Pleistocene Toroa volcanoes that have been observed in the shallow sediment column of the GSB 36 . Moreover, volcanic sequences representing Miocene volcanism have also been reported onshore 37 and from an offshore well 38 in the GSB, while Holocene volcanic activities were reported on the northern island of Zealandia 39 .…”

Geochemical characteristics and depositional environments of the Narimba Formation source rock, Bass Basin, Australia

“…According to the data displayed in Table 4, the isoprenoids/n-alkanes ratios used in this study are the Pr/nC 17 and Ph/nC 18 ratios (Table 4). These two parameters indicate biodegradation, maturation and diagenetic state of a source rock (Peters et al 2005;Jumat et al 2018;Osli et al 2019). Correlation of the two ratios by cross-plot can define the paleodepositional environment of the Narimba Formation (Peters et al 2005).…”