STRATIGRAPHIC ANALYSIS OF THE ARATU STAGE (LOWER CRETACEOUS), RECÔNCAVO BASIN (BRAZIL), WITH HYDROCARBON RESERVOIR ROCKS

The section between the 7 and 11 electric markers in the Aratu Stage of the Recôncavo Basin (Lower Cretaceous) has been studied in order to perform a stratigraphic analysis. This section bear reservoir rocks known as Imbé, Cambuqui and Miranga sandstones. It produces petroleum in fields like Miranga, Araçás, Taquipe, Miranga Norte and Imbé.The isopach map showed a general trend of increased subsidence for south and southeast. A series of structural lows surround the platform region known as Quiricó High. Southwestward, the Taquipe Canyon is an indication of the lake deepening in that region.In terms of depositional systems, it was interpreted that the Aratu Stage presented a river-dominated deltaic system all over its depositional history. In the proximal regions, located to the north and northwest, the main facies belong to the fluvial and delta plain associations and to the delta front and prodelta in the most distal system. The isolithic map and the sand percentage map indicates a main axial sand distribution. The main sedimentary inflow comes from north and northwest. Near the southeastern faulted border there is a slight contribution from the alluvial fans attached to the Salvador fault.As a natural consequence, the stratigraphic sections showed a decrease of sand south and southeastward as well as the Spontaneous Potential (SP) logs indicate a progressive change from fluvial (normal bell shapes) to deltaic patterns (inverted bell shapes).The sedimentary cyclicity is strongly depicted in the Aratu section. Part of it can be observed in resistivity and SP logs, where auto-correlation can be obtained. Peaks in the resistivity logs indicate lag deposits due to periodic lake flooding. The resistivity value, as a function of the thickness of ostracodal and fish remains calciferous sandstones and shales, allows to separate several orders of peaks (four to six orders). Conventional cyclicity analyses indicate clearly an orbital control due to precession and axial obliquity. The calculated sedimentation ratio is 60 cm/1000 years, and the time interval of 1.44 Ma for deposition of the entire section. ANÁLISE ESTRATIGRÁFICA DO ANDAR ARATU (CRETÁCIO INFERIOR), BACIA RECÔNCAVO (BRASIL), COM ROCHAS RESERVATÓRIO DE HIDROCARBONETOS Este trabalho efetua uma análise estratigráfica da seção entre os marcos elétricos 7 e 11, no Andar Aratu, da Bacia do Recôncavo (Cretáceo Inferior). Esta seção possui rochas reservatório conhecidas como arenitos de Imbé, Cambuqui e Miranga. Produz petróleo em campos como Miranga, Araçás, Taquipe, Miranga Norte e Imbé.O mapa de isopacas mostrou uma tendência geral de aumento da subsidência para o sul e sudeste. Uma série de baixos estruturais cercam a região da plataforma conhecida como a elevação Quiricó. A sudoeste, o canyon de Taquipe constitui uma indicação do aprofundamento do lago naquela região.Os dados obtidos indicam que o Andar Aratu apresentou um sistema deltaico dominado por rio em toda a sua história deposicional. Nas regiões proximais, localizadas a norte e noroeste, as principais facies pertencem às associações fluvial e planicie deltaica, marcando a área mais distal do sistema deposicional, a frente deltaica e o prodelta. O mapas de isolinhas e de percentagem de areia indicam que a distribuição de areia é sobretudo axial. O principal influxo sedimentar vem do norte e do noroeste. Perto da fronteira com a falha do sudeste há uma pequena contribuição de leques aluviais associados à falha de Salvador.Como consequência natural, as seções estratigráficas mostraram um decréscimo de areia para sul e sudeste. Os registros geofisicos de Potencial Espontâneo indicam uma mudança progressiva dos padrões fluviais (em forma de sino) para padrões deltaicos (em forma de sino invertido).A ciclicidade sedimentar é fortemente representada no Andar Aratu. Parte dela pode ser observada nos registros geofísicos de resistividade e de Potencial Espontâneo. Picos nos registros de resistividade indicam inundações periódicas do ambiente lacustre. O valor da resistividade, dependente da espessura de arenitos calcários e xistos com vestigions de ostracodes e peixes, permite separar várias ordens de picos (quatro a seis ordens). Análises de ciclicidade convencionais indicam claramente um controle orbital devido a precessão e obliquidade axial. A taxa de sedimentação calculada é de 60 cm / 1000 anos, correspondente ao intervalo de tempo de deposição de toda a seção (andar Aratu) de 1,44 Ma. Palavras-chave: Exploração de Petróleo. Mapas de Isopacas. Mapas de Isolinhas. Resistividade. Análises de Ciclicidade. Controle Orbital. Sistemas Deposicionais. Sistema Deltaico Dominado por Rio.

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Lower Cretaceous stratigraphic characteristics and tectonic control of the eastern depression, North Yellow Sea Basin, North China

Canadian Journal of Earth Sciences ◽

10.1139/cjes-2019-0074 ◽

2020 ◽

Vol 57 (10) ◽

pp. 1180-1192

Author(s):

Zhen Zhang ◽

Rihui Cheng ◽

Yanjie Shen ◽

Liaoliang Wang ◽

Xiaoqiang Hu ◽

...

Keyword(s):

Yellow Sea ◽

Lower Cretaceous ◽

North China ◽

Strike Slip ◽

Lateral Movement ◽

Third Order ◽

Reservoir Rocks ◽

North Yellow Sea ◽

The North

The Lower Cretaceous of the eastern depression in the North Yellow Sea Basin is a set of residual strata that can be divided into K1sq1 and K1sq2 sequences. There are four lithology–lithofacies architectures summarized in the third-order sequences of wells W5, W3, W1, W9, W16, W7, W8, and W10, and they are the coarse–fine–coarse, asymmetric coarse–fine, asymmetric fine–coarse, and interbedded coarse and fine. F1, F4, F6, and F7, which are strike-slip faults, were dominant during the Early Cretaceous, and controlled the eastern depression to undergo right-lateral movement from transtension to transpression. The tectonic movement controlled different stratigraphic structure in different areas, and the fan bodies deposited along the basin margin and progradated into the basin center. The sequence models under extensional and strike-slip setting were established respectively. The transtension–transpression movement controlled the development of the sandstones in the Lower Cretaceous and improved the quality of the reservoir rocks.

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A Research for Division and Correlation of Fuyu Oil Layer in Northern Honggang Area

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.962-965.622 ◽

2014 ◽

Vol 962-965 ◽

pp. 622-625

Author(s):

Xi Cheng Cao ◽

Ming Ming Tang

Keyword(s):

Songliao Basin ◽

Western Slope ◽

Delta Front ◽

The West ◽

Delta Plain ◽

The North ◽

Facies Types

Northern Honggang Area is situated in the north of Daan-Honggang terraces, southern Songliao Basin, bounded on the west of the western slope, on the northeast by Cologne sag, and on the southeast by Changling sag. The facies types of Northern Honggang District are mainly delta. The upper part of Fuyu oil layer is dominated by delta-front facies, the lower part is dominated by delta-plain facies.

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Analysis on Basic Conditions and Main Control Factors of Accumulation in Eastern Area of Yishan Slope of Ordos Basin

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.524-527.10 ◽

2012 ◽

Vol 524-527 ◽

pp. 10-15

Author(s):

Bao Hong Shi ◽

Juan Wang ◽

Yan Zhang

Keyword(s):

Ordos Basin ◽

Petroleum Reservoirs ◽

Delta Front ◽

Eastern Area ◽

Delta Plain ◽

Hydrocarbon Reservoir ◽

Control Factors ◽

Cap Rock ◽

And Migration ◽

Sand Bodies

The group of reservoir and cap-rock in Chang4+5 and Chang6 has good basic conditions of accumulation in eastern area of Yishan Slope of Ordos Basin, because it located up the high quality sources rocks (Chang7) and had a lot of hydrocarbon migrated from western areas. The reservoirs were the sand bodies formed in the distributary channels of delta plain and subaqueous distributary channels of delta front. The cap-rocks were the mudstones and compacted siltites formed in the floodplain and interdistributary areas.They composed lithologic traps. The types of petroleum reservoirs belong to lithologic hydrocarbon reservoir. The distribution of oil layers controlled by depositional microfacies and the excellent quality group of reservoir and cap-rock and migration conditions.

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The Upper Band-Better Bed sequence (Lower Coal Measures, Westphalian A) in the central and south Pennine area of England

Geological Magazine ◽

10.1017/s0016756800014163 ◽

1990 ◽

Vol 127 (1) ◽

pp. 55-74 ◽

Cited By ~ 23

Author(s):

J. I. Chisholm

Keyword(s):

Initial Period ◽

Geographical Area ◽

Large Body ◽

Open Water ◽

Delta Front ◽

The West ◽

Entire Area ◽

Delta Plain ◽

The North ◽

Facies Types

AbstractAn analysis of outcrop and borehole information relating to the strata between the Upper Band and Better Bed coals of the central and south Pennines shows that two lithological facies can be recognized within a cyclic sequence of mudstones, siltstones and sandstones. In one facies, sandstones and siltstones contain abundant mica, and argillaceous beds are neutral grey in colour. Petrographically the sandstones are feldspathic but contain little lithic material other than multigrain quartz. In the other facies, mica is much less common, argillaceous beds are greenish grey, and sandstones and siltstones contain a notable proportion of chloritic lithoclasts. The sediments of both facies were deposited in lower delta plain/shallow-water delta environments, and palaeocurrent measurements show that the micaceous facies was supplied from the north or east while the green facies came in from the west.Three named divisions of the sequence are based on recognition of the two facies types. They correspond roughly with three upward-coarsening transgressive–regressive sedimentary cycles of presumed eustatic origin. In the lowest part of the succession (Shibden division) the main clastic input was of the micaceous type. Sandstones are found only in the north of the basin, where they form a series of superimposed delta-front bodies. Mudstones were deposited elsewhere, in a large body of open water which, although linked to the sea, was generally of lowered salinity. The restriction of the delta-front sandstones to the same geographical area over a long period of time is attributed to differential subsidence of the basin across deep-seated structures.The sediments of the overlying Brighouse division belong to the green facies, and the source of the elastics lay to the west. After an initial period of mudstone deposition in an extensive, apparently non-marine, body of open water, fluviodeltaic sand and silt spread across the entire area. There is no obvious control of sandstone distribution by basement structures.The succeeding Bradley Wood division includes sediments of both micaceous and green facies. A lobe of medium-grained micaceous sandstone around Sheffield (Thurlstone Channel) represents a fluvial incursion from the east and a linear body of fine-grained green-facies sandstone south of Chesterfield (Bole Hill Channel) represents a similar incursion from the west. Elsewhere, small units of finer-grained elastics are probably deltaic deposits linked to the same sources. The location of the channel sand-bodies suggests control by deep-seated fractures.

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Depositional model and sequential evolution of the upper Quintuco Formation in its type area: implications for paleogeographic reconstructions for the southern Neuquén Basin during the Valanginian

Andean geology ◽

10.5027/andgeov43n2-a04 ◽

2016 ◽

Vol 43 (2) ◽

pp. 215 ◽

Cited By ~ 2

Author(s):

Mariana S. Olivo ◽

Ernesto Schwarz ◽

Gonzalo D. Veiga

Keyword(s):

Source Area ◽

Evolutionary Stage ◽

Delta Front ◽

Sequence Stratigraphic ◽

Architectural Analysis ◽

Delta Plain ◽

Stratigraphic Analysis ◽

Facies Associations ◽

Neuquen Basin ◽

Neuquén Basin

The Quintuco Formation (Berriasian-early Valanginian) in central Neuquén province comprise marine, transitional and continental deposits. These deposits were included in several regional stratigraphic studies since the 80’s but receiving little attention in terms of detailed facies analysis, palaeoenvironmental reconstructions and evolution. Understanding the evolutionary stage corresponding to cusp section of the Quintuco Formation and its relation with basal deposits of the Mulichinco Formation, is key to estimate the magnitude of associated change to the event of basin reconfiguration occurred in the early later Valanginian. In order to reconstruct the final stages of the evolution of the Quintuco Formation in its type locality (Sierra de la Vaca Muerta), a facial, architectural and sequence-stratigraphic analysis of the uppermost interval is presented. The study comprise the sedimentological description and interpretation of facies, combined with architectural analysis of key intervals. This allowed the identification of 7 facies associations, which represent the accumulation in prodelta (FA 1), delta front (FA 2 and FA 3), distal delta plain (FA 4 y FA 5) and proximal delta plain (FA 6 and FA 7). Subsequently, the spatial distribution of the different facies associations were analyzed and key surfaces related to significant changes in the depositional settings were identified across the investigated region. In this context, sequence-stratigraphic analysis of the studied interval was addressed and stacking patterns of the successions and vertical evolution of the interval are discussed. The upper interval of the Quintuco Formation represents the development of a deltaic system, where fluvial processes were dominant, but waves affected the off-axis parts of the system. The proximal areas were located towards the southwest with prodelta settings located toward the east. The delta system was built by successive shallowing-upward successions (15-40 m), bounded by regional transgressive surfaces, and with a long-term progradational staking. The reconstructed paleogeography for the last evolutionary stage of the Quintuco Formation suggest a well-established source area from the west-southwest, that would represent a new insight for paleogeographic settings for the southern Neuquén Basin during the Valanginian.

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The Gronlid crossing, Saskatchewan Provincial Highway No. 6 at the Saskatchewan River

Canadian Geotechnical Journal ◽

10.1139/t82-040 ◽

1982 ◽

Vol 19 (3) ◽

pp. 360-380 ◽

Cited By ~ 4

Author(s):

R. A. Lldgren ◽

E. Karl Sauer

Keyword(s):

Lower Cretaceous ◽

River Channel ◽

Slope Instability ◽

Groundwater System ◽

Regional Geology ◽

Northeastern Part ◽

Stratigraphic Analysis ◽

The North ◽

River Hydraulics ◽

Swan River

A traffic connection between Regina and the northeastern part of Saskatchewan required a crossing of the Saskatchewan River north of Gronlid. Slope instability developed in lacustrine and deltaic sands on the approaches to a ferry site installed in the early 1960s. Alternative ferry sites were considered but a river hydraulics study showed that other sites would not offer any improvement. The creation of a reservoir by projected dam at Nipawin and potential mining development in the area added incentive for the construction of a bridge to replace the original ferry installation.Valuable information was obtained from the ferry site for locating the new bridge and designing the approach roadways. It was possible to locate the bridge and approaches to minimize seepage, foundation, and slope instability problems in a deposit of over 100 m of saturated interbedded deltaic sand, lacustrine silt, and clay. A major artesian groundwater system was found in the bedrock sand of the Swan River Group, whereas groundwater conditions in the surficial stratified drift were mainly hydrostatic.The regional geology was used as a basis for detailed stratigraphic analysis at the site. The stratigraphy consisted of Lower Cretaceous sand and clay shale units underlying a dense unoxidized till. The site geology was divided into three parts: (1) the south valley approach, (2) the river channel crossing, and (3) the north valley approach. The bridge was completed in the summer of 1980.

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Palynological indications for Silurian – earliest Devonian age strata in the Netherlands

Netherlands Journal of Geosciences – Geologie en Mijnbouw ◽

10.1017/njg.2020.20 ◽

2021 ◽

Vol 100 ◽

Author(s):

Alexander J.P. Houben ◽

Geert-Jan Vis

Keyword(s):

The Netherlands ◽

Core Material ◽

Late Devonian ◽

Time Interval ◽

The South ◽

Early Devonian ◽

The North ◽

Depositional Settings ◽

Palynological Study ◽

Devonian Age

Abstract Knowledge of the stratigraphic development of pre-Carboniferous strata in the subsurface of the Netherlands is very limited, leaving the lithostratigraphic nomenclature for this time interval informal. In two wells from the southwestern Netherlands, Silurian strata have repeatedly been reported, suggesting that these are the oldest ever recovered in the Netherlands. The hypothesised presence of Silurian-aged strata has not been tested by biostratigraphic analysis. A similar lack of biostratigraphic control applies to the overlying Devonian succession. We present the results of a palynological study of core material from wells KTG-01 and S05-01. Relatively low-diversity and poorly preserved miospore associations were recorded. These, nonetheless, provide new insights into the regional stratigraphic development of the pre-Carboniferous of the SW Netherlands. The lower two cores from well KTG-01 are of a late Silurian (Ludlow–Pridoli Epoch) to earliest Devonian (Lochkovian) age, confirming that these are the oldest sedimentary strata ever recovered in the Netherlands. The results from the upper cored section from the pre-Carboniferous succession in well KTG-01 and the cored sections from the pre-Carboniferous succession in well S05-01 are more ambiguous. This inferred Devonian succession is, in the current informal lithostratigraphy of the Netherlands, assigned to the Banjaard group and its subordinate Bollen Claystone formation, of presumed Frasnian (i.e. early Late Devonian) age. Age-indicative Middle to Late Devonian palynomorphs were, however, not recorded, and the overall character of the poorly preserved palynological associations in wells KTG-01 and S05-01 may also suggest an Early Devonian age. In terms of lithofacies, however, the cores in well S05-01 can be correlated to the upper Frasnian – lower Famennian Falisolle Formation in the Campine Basin in Belgium. Hence, it remains plausible that an unconformity separates Silurian to Lower Devonian strata from Upper Devonian (Frasnian–Famennian) strata in the SW Netherlands. In general, the abundance of miospore associations points to the presence of a vegetated hinterland and a relatively proximal yet relatively deep marine setting during late Silurian and Early Devonian times. This differs markedly from the open marine depositional settings reported from the Brabant Massif area to the south in present-day Belgium, suggesting a sediment source to the north. The episodic presence of reworked (marine) acritarchs of Ordovician age suggests the influx of sedimentary material from uplifted elements on the present-day Brabant Massif to the south, possibly in relation to the activation of a Brabant Arch system.

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Geology and biostratigraphy of the Jurassic and lower cretaceous series to the north of the Lhasa Block (Tibet, China)

Geodinamica Acta ◽

10.1080/09853111.1987.11105148 ◽

1987 ◽

Vol 1 (4-5) ◽

pp. 313-325 ◽

Cited By ~ 18

Author(s):

Jean Marcoux ◽

Jacques Girardeau ◽

Eric Fourcade ◽

Jean-Paul Bassoullet ◽

Jean Philip ◽

...

Keyword(s):

Lower Cretaceous ◽

The North

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New multituberculate mammal from the Early Cretaceous of eastern North America

Canadian Journal of Earth Sciences ◽

10.1139/e2012-051 ◽

2013 ◽

Vol 50 (3) ◽

pp. 315-323 ◽

Cited By ~ 4

Author(s):

Richard L. Cifelli ◽

Cynthia L. Gordon ◽

Thomas R. Lipka

Keyword(s):

North America ◽

Iberian Peninsula ◽

Early Cretaceous ◽

North American ◽

Lower Cretaceous ◽

Late Jurassic ◽

Relative Length ◽

Central Position ◽

Eastern North America ◽

The North

Multituberculates, though among the most commonly encountered mammalian fossils of the Mesozoic, are poorly known from the North American Early Cretaceous, with only one taxon named to date. Herein we describe Argillomys marylandensis, gen. et sp. nov., from the Early Cretaceous of Maryland, based on an isolated M2. Argillomys represents the second mammal known from the Arundel Clay facies of the Patuxent Formation (Lower Cretaceous: Aptian). Though distinctive in its combination of characters (e.g., enamel ornamentation consisting of ribs and grooves only, cusp formula 2:4, presence of distinct cusp on anterobuccal ridge, enlargement of second cusp on buccal row, central position of ultimate cusp in lingual row, great relative length), the broader affinities of Argillomys cannot be established because of non-representation of the antemolar dentition. Based on lack of apomorphies commonly seen among Cimolodonta (e.g., three or more cusps present in buccal row, fusion of cusps in lingual row, cusps strongly pyramidal and separated by narrow grooves), we provisionally regard Argillomys as a multituberculate of “plagiaulacidan” grade. Intriguingly, it is comparable in certain respects to some unnamed Paulchoffatiidae, a family otherwise known from the Late Jurassic – Early Cretaceous of the Iberian Peninsula.

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Geodynamics and Oil and Gas Potential of the Yenisei-Khatanga Basin (Polar Siberia)

Minerals ◽

10.3390/min8110510 ◽

2018 ◽

Vol 8 (11) ◽

pp. 510 ◽

Cited By ~ 5

Author(s):

Valery Vernikovsky ◽

Georgy Shemin ◽

Evgeny Deev ◽

Dmitry Metelkin ◽

Nikolay Matushkin ◽

...

Keyword(s):

Lower Cretaceous ◽

Oil And Gas ◽

Foreland Basin ◽

Gas Reservoirs ◽

The North ◽

Western Arctic ◽

Folded Structures ◽

Gas Potential ◽

First Time ◽

North Western

The geodynamic development of the north–western (Arctic) margin of the Siberian craton is comprehensively analyzed for the first time based on our database as well as on the analysis of published material, from Precambrian-Paleozoic and Mesozoic folded structures to the formation of the Mesozoic-Cenozoic Yenisei-Khatanga sedimentary basin. We identify the main stages of the region’s tectonic evolution related to collision and accretion processes, mainly subduction and rifting. It is demonstrated that the prototype of the Yenisei-Khatanga basin was a wide late Paleozoic foreland basin that extended from Southern Taimyr to the Tunguska syneclise and deepened towards Taimyr. The formation of the Yenisei-Khatanga basin, as well as of the West-Siberian basin, was due to continental rifting in the Permian-Triassic. The study describes the main oil and gas generating deposits of the basin, which are mainly Jurassic and Lower Cretaceous mudstones. It is shown that the Lower Cretaceous deposits contain 90% of known hydrocarbon reserves. These are mostly stacked reservoirs with gas, gas condensate and condensate with rims. The study also presents data on oil and gas reservoirs, plays and seals in the Triassic, Jurassic and Cretaceous complexes.

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