PETROLEUM SOURCE ROCKS AND THE PREDICTIVE MODELING OF MARINE PRODUCTIVITY: PALEOGEOGRAPHIC AND PALEO-EARTH SYSTEMS CONTROLS ON LATITUDINAL DISTRIBUTION PATTERNS

2019 ◽  
pp. 219
Keyword(s):  
Predictive Modeling ◽  
Distribution Patterns ◽  
Source Rocks ◽  
Latitudinal Distribution ◽  
Earth Systems ◽  
Marine Productivity

scholarly journals Relative sorption coefficient: Key to tracing petroleum migration and other subsurface fluids

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
L. Zhang ◽  
Y. Wang ◽  
M.-W. Li ◽  
Q.-Z. Yin ◽  
W. Zhang
Keyword(s):  
Sedimentary Basins ◽  
Distribution Patterns ◽  
Polar Compounds ◽  
Source Rocks ◽  
Polar Molecules ◽  
Sorption Coefficient ◽  
Petroleum Migration ◽  
New Findings ◽  
Novel Concept ◽  
Incorrect Information

AbstractThe accumulation and spatial distribution of economically important petroleum in sedimentary basins are primarily controlled by its migration from source rocks through permeable carrier beds to reservoirs. Tracing petroleum migration entails the use of molecular indices established according to sorption capacities of polar molecules in migrating petroleum. However, little is known about molecular sorption capacities in natural migration systems, rendering these indices unreliable. Here, we present a new approach based on a novel concept of relative sorption coefficient for quantitatively assessing sorption capacities of polar molecules during natural petroleum migration. Using this approach, we discovered previously unrecognized “stripping” and “impeding” effects that significantly reduce the sorption capacities of polar compounds. These discoveries provide new insights into the behaviors of polar compounds and can easily explain why traditional molecular indices yield incorrect information about petroleum migration. In light of these new findings, we established new molecular indices for tracing petroleum migration. We demonstrate via case studies that the newly established indices, unlike traditional molecular indices, are reliable and effective in tracing petroleum migration. Our approach can be applied to diverse basins around the world to reveal distribution patterns of petroleum, which would decrease environmental risks of exploration by reducing unsuccessful wells.

Geochemical migration of impurity trace elements and resultant fractal distribution patterns in source rocks

1994 ◽  
Vol 26 (4) ◽  
pp. 419-435 ◽  
Author(s):  
Yongzhang Zhou ◽  
Edward H. Chown ◽  
Guangzhi Tu ◽  
Jayanta Guha ◽  
Huangzhang Lu
Keyword(s):  
Trace Elements ◽  
Distribution Patterns ◽  
Source Rocks ◽  
Fractal Distribution

scholarly journals Geochemical characteristics and origin of hydrocarbons in the Mesoproterozoic reservoirs in the Liaoxi Depression, NE China

2019 ◽  
Vol 38 (2) ◽  
pp. 333-347 ◽  
Author(s):  
Youjun Tang ◽  
Meijun Li ◽  
Qiuge Zhu ◽  
Daxiang He ◽  
Xingchao Jiang ◽  
...  
Keyword(s):  
Molecular Marker ◽  
Source Rock ◽  
Middle Jurassic ◽  
Distribution Patterns ◽  
Geochemical Characteristics ◽  
Oil Reservoirs ◽  
Source Rocks ◽  
Ne China ◽  
Normal Alkanes ◽  
Petroleum Generation

Oil reservoirs have been discovered in the Mesoproterozoic strata in the Liaoxi Depression, NE China. In order to determine the source of oil shows of the Mesoproterozoic Gaoyuzhuang Formation and their organic geochemical characteristics, eight source rocks and reservoir cores from the Mesoproterozoic Gaoyuzhuang Formation and four source rocks from the overlying Middle Jurassic Haifanggou Formation were geochemically analysed. The distribution patterns of normal alkanes, acyclic isoprenoids, hopanes, steranes and triaromatic steroids of the Mesoproterozoic hydrocarbons from Well N-1 are consistent with those of source rock extracts from the Mesoproterozoic Gaoyuzhuang Formation in the Well L-1. The molecular marker compositions of source rock extracts from the overlying Middle Jurassic Haifanggou Formation are distinctively different from those of the Mesoproterozoic hydrocarbons. The results suggest that the Mesoproterozoic source rocks have significant petroleum generation potential. The Mesoproterozoic paleo-reservoir may be prospecting exploration targets in the Liaoxi Depression, NE China.

scholarly journals Summer Heatwave Impacts on the European Kelp Saccharina latissima Across Its Latitudinal Distribution Gradient

2021 ◽  
Vol 8 ◽  
Author(s):  
Nora Diehl ◽  
Michael Y. Roleda ◽  
Inka Bartsch ◽  
Ulf Karsten ◽  
Kai Bischof
Keyword(s):  
Distribution Patterns ◽  
Saccharina Latissima ◽  
Latitudinal Distribution ◽  
Meristematic Tissue ◽  
Local Responses ◽  
Temperature Regimes ◽  
Intraspecific Variations ◽  
Summer Temperatures ◽  
C And N ◽  
Population Resilience

Kelps are important foundation species in coastal ecosystems currently experiencing pronounced shifts in their distribution patterns caused by ocean warming. While some populations found at species’ warm distribution edges have been recently observed to decline, expansions of some species have been recorded at their cold distribution edges. Reduced population resilience can contribute to kelp habitat loss, hence, understanding intraspecific variations in physiological responses across a species’ latitudinal distribution is crucial for its conservation. To investigate potential local responses of the broadly distributed kelp Saccharina latissima to marine heatwaves in summer, we collected sporophytes from five locations in Europe (Spitsbergen, Bodø, Bergen, Helgoland, Locmariaquer), including populations exposed to the coldest and warmest local temperature regimes. Meristematic tissue from sporophytes was subjected to increasing temperatures of Δ+2, Δ+4 and Δ+6°C above the respective mean summer temperatures (control, Δ±0°C) characteristic for each site. Survival and corresponding physiological and biochemical traits were analyzed. Vitality (optimum quantum yield, Fv/Fm) and growth were monitored over time and biochemical responses were measured at the end of the experiment. Growth was highest in northern and lowest in southern populations. Overall, northern populations from Spitsbergen, Bodø and Bergen were largely unaffected by increasing summer temperatures up to Δ+6°C. Conversely, sporophytes from Helgoland and Locmariaquer were markedly stressed at Δ+6°C: occurrence of tissue necrosis, reduced Fv/Fm, and a significantly elevated de-epoxidation state of the xanthophyll cycle (DPS). The variations in phlorotannins, mannitol and tissue C and N contents were independent of temperature treatments and latitudinal distribution pattern. Pronounced site-specific variability in response to increasing temperatures implies that exceeding a threshold above the mean summer temperature exclusively affect rear-edge (southernmost) populations.

Oil migration makes the difference: regional distribution of carbonate cement δ13C in northern North Sea Tertiary sandstones

Clay Minerals ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 69-76 ◽  
Author(s):  
C. I. Macaulay ◽  
A. E. Fallick ◽  
R. S. Haszeldine ◽  
G. E. McAulay
Keyword(s):  
North Sea ◽  
Regional Distribution ◽  
Distribution Patterns ◽  
Source Rocks ◽  
Oil Migration ◽  
Bacterial Fermentation ◽  
Carbonate Cement ◽  
Carbonate Cements ◽  
Reservoir Sandstones ◽  
Northern North Sea

AbstractCarbonate cements in Tertiary reservoir sandstones from the northern North Sea have distinctive carbon isotopic compositions (δ13C). Oil migration up faults from deeper structures and biodegradation of oil pools are factors of particular importance in influencing the δ13C of carbonate cements in these sandstones. As a result, δ13C can be used as an exploration guide to locating the positions of vertical leakoff points from the Jurassic source rocks. The histogram distribution of δ13C in these carbonate cements is trimodal, with peaks at around −26, −3 and +12‰ (ranges −22 to −30, +2 to −10 and +8 to +18‰, respectively). Bacterial processes played major roles in determining this distribution, with oxidative biodegradation of oil resulting in carbonate cements with very negative compositions and bacterial fermentation resulting in the positive δ13C cements. δ13C distribution patterns may be used to differentiate Tertiary reservoir sandstones from Jurassic in the northern North Sea, and these regional carbonate cement δ13C datasets allow geologically useful inferences to be drawn from δ13C data from new sample locations.

Natural fractures at depth in the Lower Cretaceous Kuqa Depression tight sandstones: identification and characteristics

2020 ◽  
Vol 157 (8) ◽  
pp. 1299-1315
Author(s):  
Tao Nian ◽  
Yanze Li ◽  
Tao Hou ◽  
Chengqian Tan ◽  
Chao Liu
Keyword(s):  
Lower Cretaceous ◽  
Distribution Patterns ◽  
Source Rocks ◽  
Primary Role ◽  
Thrust Faults ◽  
Natural Fractures ◽  
Thin Sections ◽  
Kuqa Depression ◽  
Opening Mode

AbstractThe Kuqa Depression in the northern Tarim Basin, NW China, is characterized by fault-controlled anticlines where natural fractures may influence production. Natural fractures in the Lower Cretaceous tight sandstones in the depression have been studied using seismic profiles, borehole images, cores and thin-sections. Results show that thrust faults, two types of opening-mode macrofractures and two types of microfractures are present. Thrust faults were generated during Cenozoic N–S-directed tectonic shortening and have hydraulically linked Jurassic source rocks and Cretaceous sandstones. Opening-mode fractures can be subdivided on the basis of sizes, filling characteristics and distribution patterns. Type 1 macrofractures are barren or mainly calcite-lined. They have straight traces with widths (opening displacements) that are of the order of magnitude of 10 μm, suggesting that their primary role is that of migration channels. Type 2 macrofractures are calcite-filled opening-mode fractures. They have an elliptical or tabular shape with sharply tapering tips. Transgranular microfractures are lens-shaped and open or filled mostly by calcite; maximum widths range between 0.01 mm and 0.1 mm. Intragranular microfractures are the most common microfracture type. They are filled by calcite, feldspar or quartz. The macrofractures and transgranular microfractures have regular distributions, while most intragranular microfractures are irregularly distributed owing to their inherited origin. The results imply that natural fractures in the tight sandstones were formed as tectonic, diagenetic and natural hydraulic origins. In situ stress and cementation analyses suggest that Type 1 macrofractures and their genesis-related microfractures have controlled the present flow system of the tight sandstones.

Even and Odd Carbon Predominance Coexisting N-Alkanes in Paleogene Dark Shale in Jinhu Sag of Subei Basin

2013 ◽  
Vol 312 ◽  
pp. 871-875
Author(s):  
Ning Song ◽  
Mei Jun Li ◽  
Jin Chuan Zhang
Keyword(s):  
Organic Matter ◽  
Eastern China ◽  
Sedimentary Environment ◽  
Distribution Patterns ◽  
Depositional Environments ◽  
Source Rocks ◽  
Ancient Lake ◽  
High Gamma ◽  
Original Organic Matter ◽  
Β Carotene

Gas chromatograms of saturated hydrocarbons of shale rock extracts show three patterns of n-alkanets in the second member of Funning formation (E1f2) in Jinhu Sag of Subei basin, eastern China. Three patterns of n-alkanets are the odd-to-even carbon predominance, the even-to-odd carbon predominance, and the even and odd carbon predominance coexisting, respectively. In this paper, the characteristics of n-alkanet coexisting even and odd carbon predominance and its origin and sedimentary environment are investigated only. The short-chain n-alkanets and long-chain n-alkanets are characterized by pronounced odd carbon predominance, with the dominant carbon of nC15, nC17 and of nC25, nC27, nC29 and nC31. The mid-chain n-alkanets are dominated by even carbon predominance, with the dominant carbon of nC20 and nC22. The composition of biomarkers are characterized by phytane preference, high gamma cerate abundance, the presence of β-carotene and C24-tetracyclic terrapin, which indicate that the organic matter in source rocks deposited in an anoxic, hyper saline lacus trine environment. The biomarkers are no homogeneous, which shows that salinity and redo is not constant in pale-lacus trine. The n-alkanets are mainly derived from algae in the ancient lake and macro pyres on land or around the edges of the ancient lake. The n-alkanets distribution patterns of the dark shales studied are believed not to be dependent on the redo in the depositional environments or the salinity of the water body, but to be associated with original organic matter composition.

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