GEOLOGICAL REASONING FOR THE PETROLEUM SOURCE ROCKS OF KNOWN FIELDS

1986 ◽  
Vol 26 (1) ◽  
pp. 132
Author(s):  
R.E. Chapman

Geological reasoning for the petroleum source-migration-accumulation relationships centres around petroleum composition and its variability, water composition and its variability, and stratigraphy. For example, a field with several pools of petroleum of different compositions is likely to have been sourced from several distinct source rocks that are stratigraphically associated with the reservoir rocks. If water compositions are also variable, the conclusion is reinforced. A field with several pools of petroleum of similar quality was sourced either from similar source rocks that are stratigraphically associated with the reservoirs, or from a single source that is removed from the accumulations. There are also considerations of wax content, environment of deposition of the reservoir sequence, sand/shale ratios, and faulting.Geological reasoning does not always lead to the same conclusions as geochemical reasoning. Such cases are particularly important for petroleum geology because they should lead us to a better understanding of the source-migration-accumulation relationships. Some of the remaining giant oil accumulations of the world may be in areas that would be discarded on geochemical evidence. Most of the crude oil remaining to be discovered will be in relatively few giant fields, so misunderstanding could jeopardize our future supplies.

2017 ◽  
Vol 54 (4) ◽  
pp. 227-264
Author(s):  
Ronald Johnson ◽  
Justin Birdwell ◽  
Paul Lillis

To better understand oil and bitumen generation and migration in the Paleogene lacustrine source rocks of the Uinta Basin, Utah, analyses of 182 oil samples and tar-impregnated intervals from 82 core holes were incorporated into a well-established stratigraphic framework for the basin. The oil samples are from the U.S. Geological Survey Energy Resources Program Geochemistry Laboratory Database; the tar-impregnated intervals are from core holes drilled at the Sunnyside and P.R. Spring-Hill Creek tar sands deposits. The stratigraphic framework includes transgressive and regressive phases of the early freshwater to near freshwater lacustrine interval of Lake Uinta and the rich and lean zone architecture developed for the later brackish-to-hypersaline stages of the lake. Two types of lacustrine-sourced oil are currently recognized in the Uinta Basin: (1) Green River A oils, with high wax and low β-carotane contents thought to be generated by source rocks in the fresh-to-brackish water lacustrine interval, and (2) much less common Green River B oils, an immature asphaltic oil with high β-carotane content thought to be generated by marginally mature to mature source rocks in the hypersaline lacustrine interval. Almost all oil samples from reservoir rocks in the fresh-to-brackish water interval are Green River A oils; however four samples of Green River A oils were present in the hypersaline interval, which likely indicates vertical migration. In addition, two samples of Green River B oil are from intervals that were assumed to contain only Green River A oil. Tar sand at the P.R. Spring-Hill Creek deposit are restricted to marginal lacustrine and fluvial sandstones deposited during the hypersaline phase of Lake Uinta, suggesting a genetic relationship to Green River B oils. Tar sand at the Sunnyside deposit, in contrast, occur in marginal lacustrine and alluvial sandstones deposited from the early fresh to nearly freshwater phase of Lake Uinta through the hypersaline phase. The Sunnyside deposit occurs in an area with structural dips that range from 7 to 14 degrees, and it is possible that some tar migrated stratigraphically down section.


Author(s):  
Lars Stemmerik ◽  
Gregers Dam ◽  
Nanna Noe-Nygaard ◽  
Stefan Piasecki ◽  
Finn Surlyk

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Stemmerik, L., Dam, G., Noe-Nygaard, N., Piasecki, S., & Surlyk, F. (1998). Sequence stratigraphy of source and reservoir rocks in the Upper Permian and Jurassic of Jameson Land, East Greenland. Geology of Greenland Survey Bulletin, 180, 43-54. https://doi.org/10.34194/ggub.v180.5085 _______________ Approximately half of the hydrocarbons discovered in the North Atlantic petroleum provinces are found in sandstones of latest Triassic – Jurassic age with the Middle Jurassic Brent Group, and its correlatives, being the economically most important reservoir unit accounting for approximately 25% of the reserves. Hydrocarbons in these reservoirs are generated mainly from the Upper Jurassic Kimmeridge Clay and its correlatives with additional contributions from Middle Jurassic coal, Lower Jurassic marine shales and Devonian lacustrine shales. Equivalents to these deeply buried rocks crop out in the well-exposed sedimentary basins of East Greenland where more detailed studies are possible and these basins are frequently used for analogue studies (Fig. 1). Investigations in East Greenland have documented four major organic-rich shale units which are potential source rocks for hydrocarbons. They include marine shales of the Upper Permian Ravnefjeld Formation (Fig. 2), the Middle Jurassic Sortehat Formation and the Upper Jurassic Hareelv Formation (Fig. 4) and lacustrine shales of the uppermost Triassic – lowermost Jurassic Kap Stewart Group (Fig. 3; Surlyk et al. 1986b; Dam & Christiansen 1990; Christiansen et al. 1992, 1993; Dam et al. 1995; Krabbe 1996). Potential reservoir units include Upper Permian shallow marine platform and build-up carbonates of the Wegener Halvø Formation, lacustrine sandstones of the Rhaetian–Sinemurian Kap Stewart Group and marine sandstones of the Pliensbachian–Aalenian Neill Klinter Group, the Upper Bajocian – Callovian Pelion Formation and Upper Oxfordian – Kimmeridgian Hareelv Formation (Figs 2–4; Christiansen et al. 1992). The Jurassic sandstones of Jameson Land are well known as excellent analogues for hydrocarbon reservoirs in the northern North Sea and offshore mid-Norway. The best documented examples are the turbidite sands of the Hareelv Formation as an analogue for the Magnus oil field and the many Paleogene oil and gas fields, the shallow marine Pelion Formation as an analogue for the Brent Group in the Viking Graben and correlative Garn Group of the Norwegian Shelf, the Neill Klinter Group as an analogue for the Tilje, Ror, Ile and Not Formations and the Kap Stewart Group for the Åre Formation (Surlyk 1987, 1991; Dam & Surlyk 1995; Dam et al. 1995; Surlyk & Noe-Nygaard 1995; Engkilde & Surlyk in press). The presence of pre-Late Jurassic source rocks in Jameson Land suggests the presence of correlative source rocks offshore mid-Norway where the Upper Jurassic source rocks are not sufficiently deeply buried to generate hydrocarbons. The Upper Permian Ravnefjeld Formation in particular provides a useful source rock analogue both there and in more distant areas such as the Barents Sea. The present paper is a summary of a research project supported by the Danish Ministry of Environment and Energy (Piasecki et al. 1994). The aim of the project is to improve our understanding of the distribution of source and reservoir rocks by the application of sequence stratigraphy to the basin analysis. We have focused on the Upper Permian and uppermost Triassic– Jurassic successions where the presence of source and reservoir rocks are well documented from previous studies. Field work during the summer of 1993 included biostratigraphic, sedimentological and sequence stratigraphic studies of selected time slices and was supplemented by drilling of 11 shallow cores (Piasecki et al. 1994). The results so far arising from this work are collected in Piasecki et al. (1997), and the present summary highlights the petroleum-related implications.


2015 ◽  
Vol 33 (4) ◽  
pp. 381-387 ◽  
Author(s):  
A. Majhi ◽  
Y. K. Sharma ◽  
V. S. Kukreti ◽  
K. P. Bhatt ◽  
R. Khanna

2006 ◽  
Vol 4 (1) ◽  
pp. 351-356
Author(s):  
Marlena Owczuk

The development of the automotive industry in the world causes high environmental degradation, the main source of this degradation is engine emissions. It is necessary to introduce biofuels prepared from renewable energy sources to the market due to the limited reserve of crude oil and environmental protection. Appropriate new modifications in law regulations have been prepared in European Union. Introducing alternative fuels can reduce the emissions of harmful gases and also decrease the level of pollutions in the environment.


1987 ◽  
Vol 133 ◽  
pp. 141-157
Author(s):  
F.G Christiansen ◽  
H Nøhr-Hansen ◽  
O Nykjær

During the 1985 field season the Cambrian Henson Gletscher Formation in central North Greenland was studied in detail with the aim of evaluating its potential as a hydrocarbon source rock. The formation contains organic rich shale and carbonate mudstone which are considered to be potential source rocks. These are sedimentologically coupled with a sequence of sandstones and coarse carbonates which might be potential reservoir rocks or migration conduits. Most of the rocks exposed on the surface are, however, thermally mature to postrnature with respect to hydrocarbon generation, leaving only few chances of finding trapped oil in the subsurface of the area studied in detail.


Author(s):  
S. A. Zolina ◽  
I. A. Kopytin ◽  
O. B. Reznikova

In 2018 the United States surpassed Saudi Arabia and Russia to become the largest world oil producer. The article focuses on the mechanisms through which the American shale revolution increasingly impacts functioning of the world oil market. The authors show that this impact is translated to the world oil market mainly through the trade and price channels. Lifting the ban on crude oil exports in December 2015 allowed the United States to increase rapidly supply of crude oil to the world oil market, the country’s share in the world crude oil exports reached 4,4% in 2018 and continues to rise. The U.S. share in the world petroleum products exports, on which the American oil sector places the main stake, reached 18%. In parallel with increasing oil production the U.S. considerably shrank crude oil import that forced many oil exporters to reorient to other markets. Due to high elasticity of tight oil production to the oil price increases oil from the U.S. has started to constrain the world oil price from above. According to the majority of authoritative forecasts, oil production in the U.S. will continue to increase at least until 2025. Since 2017 the tendency to the increasing expansion of supermajors into American unconventional oil sector has become noticeable, what will contribute to further strengthening of the U.S. position in the world oil market and accelerate its restructuring.  


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