THE PETROLEUM GEOCHEMISTRY OF OILS AND SOURCE ROCKS FROM THE NORTHERN BONAPARTE BASIN, OFFSHORE NORTHERN AUSTRALIA

2000 ◽  
Vol 40 (1) ◽  
pp. 257 ◽  
Author(s):  
J.C. Preston ◽  
D.S. Edwards
Keyword(s):  
Source Rock ◽  
Early Cretaceous ◽  
Late Jurassic ◽  
Structural Complexity ◽  
Source Rocks ◽  
Geochemical Data ◽  
Northwestern Part ◽  
Migration Patterns ◽  
Catchment Areas ◽  
Migration Pathways

Geochemical data from oils and source rock extracts have been used to delineate the active petroleum systems of the Northern Bonaparte Basin. The study area comprises the northeastern portion of the Territory of Ashmore and Cartier Islands, and the western part of the Zone of Co-operation Area A, and is specifically concerned with the wells located on and between the Laminaria and Flamingo highs. The oils and condensates from this region can be divided into two distinct chemical groups which correspond with the reservoir types, namely, a smaller group recovered from fracture porosity within the Early Cretaceous Darwin Formation, and a larger group reservoired in sandstones of the Middle-to-Late Jurassic Plover and Elang formations. The oils recovered from the Darwin Formation have a marine source affinity and correlate with sediment extracts from the underlying Early Cretaceous Echuca Shoals Formation. The Elang/ Plover-reservoired oils, which include all the commercial accumulations, were divided into two end-member families; the first includes the relatively land-plant- influenced oils from the northwestern part of the area (e.g. Laminaria, Corallina, Buffalo and Jahal fields), the second includes the relatively marine-influenced oils to the southeast (e.g. Bayu-Undan fields). Another oil family comprises the geographically and geochemically intermediate oils of the Elang and Kakatua fields and adjacent areas. While none of the oils can be uniquely correlated with a single source unit, they show geochemical similarities with Middle-to-Late Jurassic source rock extracts. Organic-rich rocks within the Plover and Elang formations are the major source of hydrocarbons for this area. The range in geochemistry of the Elang/Plover-reservoired oils may arise from facies variation within these sediments, but is more probably due to the localised additional input of hydrocarbons generated from thermally mature organic-rich claystone seals that overlie the Elang reservoir in catchment areas and traps; i.e. from the Frigate Formation for the northwestern oil family and from the Flamingo Group for the southeastern oil family. The short-range migration patterns dictated by the structural complexity of the basin are reflected in the closeness with which variations in the geochemical character of the accumulated liquids track variations in the character of source-seal lithologies. The length of migration pathways can, therefore, be inferred from the similarity or otherwise of source-seal characters with those of the hydrocarbon accumulations themselves. The resulting observations may challenge existing ideas concerning migration patterns, hydrocarbon prospectivity and prospect risking within the Northern Bonaparte Basin.

HYDROCARBON GENERATION AND EXPULSION FROM EARLY CRETACEOUS SOURCE ROCKS IN THE BROWSE BASIN, NORTH WEST SHELF, AUSTRALIA: A SMALL ANGLE NEUTRON SCATTERING STUDY

2004 ◽  
Vol 44 (1) ◽  
pp. 151 ◽  
Author(s):  
A.P. Radlinski ◽  
J.M. Kennard ◽  
D.S. Edwards ◽  
A.L. Hinde ◽  
R. Davenport
Keyword(s):  
Neutron Scattering ◽  
Pore Size ◽  
Source Rock ◽  
Early Cretaceous ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Source Rocks ◽  
Geochemical Data ◽  
Hydrocarbon Generation ◽  
North West

Small Angle Neutron Scattering (SANS) analyses were carried out on 165 potential source rocks of Late Jurassic–Early Cretaceous age from nine wells in the Browse Basin (Adele–1, Argus–1, Brecknock South–1, Brewster–1A, Carbine–1, Crux–1, Dinichthys–1, Gorgonichthys–1 and Titanichthys–1). Samples from Brewster–1A and Dinichthys–1 were also analysed using the Ultra Small Angle Neutron Scattering (USANS) technique.The SANS/USANS data detect the presence of generated bitumen and mobile hydrocarbons in pores and are pore-size specific. As the pore-size range in mudstones extends from about 0.001–30 μm, the presence of bitumen in the small pores detected by SANS indicates the depth of onset of hydrocarbon generation, whereas the presence of bitumen and mobile hydrocarbons in the largest pores detected by USANS indicates a significant saturation and the onset of expulsion.Although geochemical data imply the existence of a potential gas and oil source rock in the Lower Cretaceous section (Echuca Shoals and Jamieson Formations), the SANS/USANS data indicate significant generation but little or no expulsion. This source limitation may explain poor exploration success for liquid hydrocarbons in the area. The SANS/USANS data provide evidence of intra- and inter-formational hydrocarbon migration or kerogen kinetics barriers. There is no evidence of an oil charge to the Berriasian Brewster Sandstone from the Echuca Shoals Formation, although some gas charge in Brewster–1A is possible. This novel microstructural technique can be used to independently calibrate and refine source rock generation/expulsion scenarios derived from geochemistry modelling.

AN EARLY CRETACEOUS SOURCE ROCK IN THE KENDREW TERRACE, DAMPIER SUB-BASIN?

1996 ◽  
Vol 36 (1) ◽  
pp. 477 ◽  
Author(s):  
S. Ryan-Grigor ◽  
C. M. Griffiths
Keyword(s):  
Source Rock ◽  
North Sea ◽  
Early Cretaceous ◽  
Late Jurassic ◽  
Large Scale ◽  
Free Water ◽  
Organic Content ◽  
Source Rocks ◽  
The North ◽  
Northern North Sea

The Early to Middle Cretaceous is characterised worldwide by widespread distribution of dark shales with high gamma ray readings and high organic contents defined as dark coloured mudrocks having the sedimentary, palaeoecological and geochemical characteristics associated with deposition under oxygen-deficient or oxygen-free bottom waters. Factors that contributed to the formation of the Early to Middle Cretaceous 'hot shales' are: rising sea-level, a warm equable climate which promoted water stratification, and large scale palaeogeographic features that restrict free water mixing. In the northern North Sea, the main source rock is the Late Jurassic to Early Cretaceous Kimmeridge Clay/Draupne Formation 'hot shale' which occurs within the Viking Graben, a large fault-bounded graben, in a marine environment with restricted bottom circulation and often anaerobic conditions. Opening of the basin during a major trans-gressive event resulted in flushing, and deposition of normal open marine shales above the 'hot shales'. The Late Callovian to Berriasian sediments in the Dampier Sub-basin are considered to have been deposited in restricted marine conditions below a stratified water column, in a deep narrow bay. Late Jurassic to Early Cretaceous marine sequences that have been cored on the North West Shelf are generally of moderate quality, compared to the high quality source rocks of the northern North Sea, but it should be noted that the cores are from wells on structural highs. The 'hot shales' are not very organic-rich in the northern Dampier Sub-basin and are not yet within the oil window, however seismic data show a possible reduction in velocity to the southwest in the Kendrew Terrace, suggesting that further south in the basin the shales may be within the oil window and may also be richer in organic content. In this case, they may be productive source rocks, analogous to the main source rock of the North Sea.

GEOLOGY, SOURCE ROCKS AND HYDROCARBON GENERATION IN THE CLARENCE-MORETON BASIN

1982 ◽  
Vol 22 (1) ◽  
pp. 5
Author(s):  
A. R. Martin ◽  
J. D. Saxby
Keyword(s):  
Vitrinite Reflectance ◽  
Source Rocks ◽  
Geochemical Data ◽  
Hydrocarbon Potential ◽  
Hydrocarbon Generation ◽  
Tectonic Events ◽  
History Of ◽  
Rock Eval ◽  
Coal Measures ◽  
Migration Pathways

The geology and exploration history of the Triassic-Cretaceous Clarence-Moreton Basin are reviewed. Consideration of new geochemical data ('Rock-Eval', vitrinite reflectance, gas chromatography of extracts, organic carbon and elemental analysis of coals and kerogens) gives further insights into the hydrocarbon potential of the basin. Although organic-rich rocks are relatively abundant, most source rocks that have achieved the levels of maturation necessary for hydrocarbon generation are gas-prone. The exinite-rich oil-prone Walloon Coal Measures are in most parts relatively immature. Some restraints on migration pathways are evident and igneous and tectonic events may have disturbed potentially well-sealed traps. Further exploration is warranted, even though the basin appears gas-prone and the overall prospects for hydrocarbons are only fair. The most promising areas seem to be west of Toowoomba for oil and the Clarence Syncline for gas.

scholarly journals The Depth Limit for the Formation and Occurrence of Fossil Fuel Resources

2019 ◽  
Author(s):  
Xiongqi Pang ◽  
Chengzao Jia ◽  
Kun Zhang ◽  
Maowen Li ◽  
Youwei Wang ◽  
...  
Keyword(s):  
Source Rock ◽  
Fossil Fuel ◽  
Maximum Depth ◽  
Source Rocks ◽  
Distribution Area ◽  
Geochemical Data ◽  
Burial Depth ◽  
Human Beings ◽  
Depth Limit ◽  
Active Source

Abstract. Fossil resources are valuable wealth given to human beings by nature. Many mysteries related to them have been revealed such as the origin time and distribution area, but their vertical distribution depth has not been confirmed for people’s different understanding of their origin and the big depth variations from basin to basin. Geological and geochemical data of 13,634 source rock samples from 1,286 exploration wells in six representative petroliferous basins are examined to study their Active Source Rock Depth Limits (ASDL), defined in this study as the maximum burial depth of active source rocks beyond which the source rocks no longer generate or expel hydrocarbons and become inactive, to identify the maximum depth for fossil fuel resources distribution. Theoretically, the maximum depth for the ASDLs of fossil fuel resources ranges from 3,000 m to 16,000 m, while their thermal maturities (Ro) are almost the same with Ro≈3.5±0.5 %. A higher heat flow and more oil-prone kerogen are associated with a shallower ASDL. Active source rocks and the discovered 21.6 billion tons of reserves in six representative basins in China and 52,926 oil and gas reservoirs in the 1,186 basins over the world are found to be distributed above the ASDL, illustrating the universality of such kind of depth limit. The data are deposited in the repository of the PANGAEA database: https://doi.org/10.1594/PANGAEA.900865 (Pang et al., 2019).

scholarly journals Petroleum generation modeling of the organic-rich shales of Late Jurassic – Early Cretaceous succession from Mintaq-01 well in the Wadi Hajar sub-basin, Yemen

2016 ◽  
Vol 53 (10) ◽  
pp. 1053-1072 ◽  
Author(s):  
Mohammed Hail Hakimi ◽  
Abdulghani F. Ahmed
Keyword(s):  
Source Rock ◽  
Early Cretaceous ◽  
Late Jurassic ◽  
Oil And Gas ◽  
Late Eocene ◽  
Peak Oil ◽  
Oil Generation ◽  
Petroleum Generation ◽  
Rock Characterization ◽  
Excellent Source

Late Jurassic – Early Cretaceous shales of the Naifa, Safer, and Madbi formations were studied to evaluate source rock characterization. The results of the source rock were then incorporated into basin modeling to understand the timing of hydrocarbon (HC) generation and expulsion. The Late Jurassic – Early Cretaceous shales have low to high organic matter, with total organic carbon (TOC) values in the range of 0.50%–28.01%, indicating fair to excellent source rock potential. Main oil and gas are anticipated to be generated from the Naifa, Safer, and Lam shale samples with types I and (or) II and types II–III kerogens. In contrast, the Meem samples are dominated by type III kerogen (hydrogen index, HI < 200 mg HC / g TOC), and are thus considered to be gas prone. The Late Jurassic – Early Cretaceous shale samples have temperatures of maximum pyrolysis yield (Tmax) in the range of 337–515 °C, consistent with immature to post-mature stages. The Tmax data also indicate that the Safer and Madbi shale samples have sufficient thermal maturity, i.e., peak–mature oil and gas window. The basin models indicate that the Naifa Formation is early–mature, and the onset oil generation began during the Early Miocene. The models also indicate that the main phase of oil generation in the Safer source rock began during the Late Eocene. In contrast, the Madbi source rock units had passed the peak oil generation window, and the oil was converted to gas during the Late Cretaceous to Late Eocene. The modeled HC expulsion history reveals that most oils are contributed by both Madbi units, with significant amounts of gas originating from the Meem unit.

scholarly journals Whole-rock and zircon evidence for evolution of the Late Jurassic high Sr/Y Zhoujiapuzi granite, Liaodong Peninsula, North China Craton

2021 ◽  
Author(s):  
Renyu Zeng ◽  
Mark Allen ◽  
Xiancheng Mao ◽  
Jianqing Lai ◽  
Jie Yan ◽  
...  
Keyword(s):  
Oxygen Fugacity ◽  
North China Craton ◽  
Late Jurassic ◽  
North China ◽  
Early Stage ◽  
Middle Part ◽  
Source Rocks ◽  
Geochemical Data ◽  
Low Oxygen ◽  
Liaodong Peninsula

Abstract. Middle-Late Jurassic high Sr/Y granitic intrusions are extensively exposed in the Liaodong Peninsula, in the eastern part of the North China Craton (NCC). However, the genesis of the high Sr/Y signature in these intrusions has not been studied in detail. In this study, we report results of zircon U-Pb dating, Hf isotopic analysis and zircon and whole-rock geochemical data for the Late Jurassic Zhoujiapuzi granite in the middle part of the Liaodong Peninsula. The Zhoujiapuzi granite is high-K (calc-alkaline) and peraluminous in nature, with high SiO2 (68.1–73.0 wt %) and Al2O3 (14.5–16.8 wt %), low in TFe2O3 (1.10–2.49 wt %) and MgO (0.10–0.44 wt %), and with high Sr/Y (19.9–102.0) and LaN/YbN (14.59–80.40). Morphological and chemical studies on zircon grains show that there are two stages of zircon growth, interpreted as magmatic evolution in two distinct stages. The early stage of zircons (ESZ) reflects a crystallization environment of low oxygen fugacity and high TZr-Ti (Ti-in-zircon thermometer values: 669–792 °C); the late stage of zircons (LSZ) formed with high oxygen fugacity and lower TZr-Ti (498–720 °C). LA-ICP-MS U-Pb zircon dating yielded the formation ages of the ESZ and LSZ of ~162 ± 1 Ma and ~158 ± 1 Ma, respectively, with similar εHf(t) values in the range of &amp;minus26.3– −22.8. Interpretation of the elemental and isotopic data suggests that the Zhoujiapuzi granite was a I-type granite derived from partial melting of basement in the region: ~2.17 Ga Liaoji granites. The high Sr/Y signature is most likely inherited from these source rocks. Based on the geochemical features and regional geological data, we propose that the Liaodong Peninsula in the Late Jurassic was part of a mature continental arc, with extensive melting of thick crust above the Paleo-Pacific subduction zone.

scholarly journals Reconstruction of burial history, temperature, source rock maturity and hydrocarbon generation in the northwestern Dutch offshore

2012 ◽  
Vol 91 (4) ◽  
pp. 535-554 ◽  
Author(s):  
R. Abdul Fattah ◽  
J.M. Verweij ◽  
N. Witmans ◽  
J.H. ten Veen
Keyword(s):  
Source Rock ◽  
Source Rocks ◽  
Northwestern Part ◽  
Hydrocarbon Generation ◽  
Burial History ◽  
Coal Seams ◽  
Gas Generation ◽  
Offshore Area ◽  
The North ◽  
Late Generation

Abstract3D basin modelling is used to investigate the history of maturation and hydrocarbon generation on the main platforms in the northwestern part of the offshore area of the Netherlands. The study area covers the Cleaverbank and Elbow Spit Platforms. Recently compiled maps and data are used to build the input geological model. An updated and refined palaeo water depth curve and newly refined sediment water interface temperatures (SWIT) are used in the simulation. Basal heat flow is calculated using tectonic models. Two main source rock intervals are defined in the model, Westphalian coal seams and pre-Westphalian shales, which include Namurian and Dinantian successions. The modelling shows that the pre-Westphalian source rocks entered the hydrocarbon generation window in the Late Carboniferous. In the southern and central parts of the study area, the Namurian started producing gas in the Permian. In the north, the Dinantian source rocks appear to be immature. Lower Westphalian sediments started generating gas during the Upper Triassic. Gas generation from Westphalian coal seams increased during the Paleogene and continues in present-day. This late generation of gas from Westphalian coal seams is a likely source for gas accumulations in the area.Westphalian coals might have produced early nitrogen prior to or during the main gas generation occurrence in the Paleogene. Namurian shales may be a source of late nitrogen after reaching maximum gas generating phase in the Triassic. Temperatures reached during the Mid Jurassic were sufficiently high to allow the release of non-organic nitrogen from Namurian shales.

Contrasting origins of late Mesozoic adakitic granitoids from the northwestern Jiaodong Peninsula, east China: implications for crustal thickening to delamination

2007 ◽  
Vol 144 (4) ◽  
pp. 619-631 ◽  
Author(s):  
MING-LAN HOU ◽  
YAO-HUI JIANG ◽  
SHAO-YONG JIANG ◽  
HONG-FEI LING ◽  
KUI-DONG ZHAO
Keyword(s):  
Early Cretaceous ◽  
Late Jurassic ◽  
Early Stage ◽  
Eastern China ◽  
Alkali Feldspar ◽  
Crustal Thickening ◽  
Geochemical Data ◽  
Jiaodong Peninsula ◽  
T Values ◽  
Lower Crustal

Two suites of granitoids, the Late Jurassic (158 ± 3 Ma) Linglong suite and the Early Cretaceous (130–126 Ma) Guojialing suite, crop out in the northwestern Jiaodong Peninsula, eastern China. The Linglong suite is a monzogranite, comprising alkali feldspar, plagioclase, quartz and Fe-rich biotite. The Guojialing suite includes at least five plutonic bodies of both granodiorite and monzo-granite. The rocks are composed of plagioclase, alkali feldspar, quartz, Mg-rich amphibole and Mg-rich biotite. Both the Linglong and Guojialing suites have adakitic affinity. They are enriched in LREE with high La/Yb ratios and show positive Eu anomalies. The rocks are also enriched in LILE and depleted in HFSE with high Sr/Y ratios. The Linglong granite shows very uniform Sr–Nd isotopic compositions with initial 87Sr/86Sr ratios of 0.7119–0.7126 and εNd (T) values of −21.3 to −21.6, which are similar to those of the local Neoarchaean basement. The Guojialing suite has variable initial 87Sr/86Sr ratios (0.7108–0.7120) and εNd (T) values (−10.8 to −17.2), which are distinct both from those of the Neoarchaean basement and from those of the local enriched lithospheric mantle inferred from the coeval mafic dykes in the studied area. Detailed petrological and geochemical data indicate that the Linglong suite was derived by partial melting of Neoarchaean metamorphic lower-crustal rocks at depth of > 50 km with a eclogite residue, whereas the Guojialing suite was formed by the reaction of delaminated eclogitic crust-derived melt with the upwelling asthenospheric mantle. The petrogenesis of these two contrasting adakitic granitoids suggests intensive lower-crustal delamination during Early Cretaceous times, following a crustal thickening process from the late stage of the Early Jurassic to early stage of the Late Jurassic with crustal thickness of < 32 km to > 50 km, respectively.

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