scholarly journals Geology of the Lower Cretaceous in the Falkebjerg area, Wollaston Forland, northern East Greenland

2020 ◽  
Vol 68 ◽  
pp. 155-169
Author(s):  
Stefan Piasecki ◽  
Jørgen A. Bojesen-Koefoed ◽  
Peter Alsen
Keyword(s):  
Lower Cretaceous ◽  
Depositional Environment ◽  
Depositional Environments ◽  
Petroleum Reservoir ◽  
Dinoflagellate Cysts ◽  
Marine Fauna ◽  
East Greenland ◽  
North West ◽  
The North ◽  
New Good

New data on the Lower Cretaceous Falskebugt Member (Palnatokes Bjerg Formation) and Stratumbjerg Formation in easternmost Wollaston Forland, northern East Greenland, are interpreted here. The type locality of the Falskebugt Member on the north-west corner of the Falkebjerg ridge has been revisited, and additional new good exposures were found in a riverbed just north of Falkebjerg and more in river beds on the plain further to the north, where both the Falskebugt Member and the Stratumbjerg Formation are exposed. Previously, only a limited marine fauna was reported providing a restricted middle Valanginian age of the Falskebugt Member. New fossil faunas in other parts of the Falskebugt Member suggest an early Valanginian – Hauterivian age and confirm lateral correlation with the Albrechts Bugt and Rødryggen Members of the Palnatokes Bjerg Formation. However, in places where the Falskebugt Member is exposed in contact with the lower Stratumbjerg Formation, dinoflagellate cysts from these units indicate Barremian and late Barremian ages, respectively. The stratigraphic range of the combined biostratigraphic data from the Falskebugt Member indicates an early Valanginian – late Barremian age. Dinoflagellate cysts from part of the assemblage in the Stratumbjerg Formation suggest a marginal marine/brackish water depositional environment. Comparable depositional environments are also recorded in upper Barremian sediments on Store Koldewey and in the Ladegårdsåen Formation on Peary Land much farther to the north in Greenland. The dark mudstones of the Stratumbjerg Formation show no potential for generation of liquid hydrocarbons, and the immature and poorly sorted sediments of the Falskebugt Member have little potential as a petroleum reservoir.

Depositional Environment Drive as Overpressure Generation: Study Case in “Gap” Field, North West Java Basin

2020 ◽  
Author(s):  
A., C. Prasetyo
Keyword(s):  
Clay Mineral ◽  
Depositional Environment ◽  
Mineral Content ◽  
Hydrocarbon Generation ◽  
Well Test ◽  
Burial History ◽  
The South ◽  
North West ◽  
The North ◽  
Geological Processes

Overpressure existence represents a geological hazard; therefore, an accurate pore pressure prediction is critical for well planning and drilling procedures, etc. Overpressure is a geological phenomenon usually generated by two mechanisms, loading (disequilibrium compaction) and unloading mechanisms (diagenesis and hydrocarbon generation) and they are all geological processes. This research was conducted based on analytical and descriptive methods integrated with well data including wireline log, laboratory test and well test data. This research was conducted based on quantitative estimate of pore pressures using the Eaton Method. The stages are determining shale intervals with GR logs, calculating vertical stress/overburden stress values, determining normal compaction trends, making cross plots of sonic logs against density logs, calculating geothermal gradients, analyzing hydrocarbon maturity, and calculating sedimentation rates with burial history. The research conducted an analysis method on the distribution of clay mineral composition to determine depositional environment and its relationship to overpressure. The wells include GAP-01, GAP-02, GAP-03, and GAP-04 which has an overpressure zone range at depth 8501-10988 ft. The pressure value within the 4 wells has a range between 4358-7451 Psi. Overpressure mechanism in the GAP field is caused by non-loading mechanism (clay mineral diagenesis and hydrocarbon maturation). Overpressure distribution is controlled by its stratigraphy. Therefore, it is possible overpressure is spread quite broadly, especially in the low morphology of the “GAP” Field. This relates to the delta depositional environment with thick shale. Based on clay minerals distribution, the northern part (GAP 02 & 03) has more clay mineral content compared to the south and this can be interpreted increasingly towards sea (low energy regime) and facies turned into pro-delta. Overpressure might be found shallower in the north than the south due to higher clay mineral content present to the north.

scholarly journals Stratigraphy and Depositional Environment of Mauddud Formation in Ratawi Oil wells of Southern Iraq

2021 ◽  
Vol 877 (1) ◽  
pp. 012030
Author(s):  
Maha Razaq Manhi ◽  
Hamid Ali Ahmed Alsultani
Keyword(s):  
Deep Sea ◽  
Lower Cretaceous ◽  
Depositional Environment ◽  
Carbonate Platform ◽  
Depositional Environments ◽  
Oil Wells ◽  
Oil Field ◽  
Microfacies Analysis ◽  
Thin Sections ◽  
Southern Iraq

Abstract The Mauddud Formation is Iraq’s most significant and widely distributed Lower Cretaceous formation. This Formation has been investigated at a well-23 and a well-6 within Ratawi oil field southern Iraq. In this work, 75 thin sections were produced and examined. The Mauddud Formation was deposited in a variety of environments within the carbonate platform. According to microfacies analysis studying of the Mauddud Formation contains of twelve microfacies, this microfacies Mudstone to wackestone microfacies, bioclastic mudstone to wackestone microfacies, Miliolids wackestone microfacies,Orbitolina wackestone microfacies, Bioclastic wackestone microfacies, Orbitolina packstone microfacies, Peloidal packstone microfacies, Bioclastic packstone microfacies, Peloidal to Bioclastic packstone microfacies, Bioclastic grainstone microfacies, Peloidal grainstone microfacies, Rudstone microfacies. Deep sea, Shallow open marine, Restricted, Rudist Biostrome, Mid – Ramp, and Shoals are the six depositional environments in the Mauddud Formation based on these microfacies.

scholarly journals Dinoflagellate cyst stratigraphy of the Barremian to Albian, Lower Cretaceous, North-East Greenland – a summary

1994 ◽  
Vol 160 ◽  
pp. 68-72
Author(s):  
H Nøhr-Hansen
Keyword(s):  
Lower Cretaceous ◽  
Geological Survey ◽  
Hydrocarbon Potential ◽  
Dinoflagellate Cysts ◽  
East Greenland ◽  
Dinoflagellate Cyst ◽  
North East

As part of studies of the onshore hydrocarbon potential in East Greenland undertaken by the Geological Survey of Greenland (GGU), a project was initiated with the purpose of describing the dinoflagellate cyst stratigraphy of the Lower Cretaceous succession in East Greenland (72°76°N) and correlating the exposed sections throughout the region (Nøhr-Hansen, 1993). Based on the rather sporadic occurrence of macrofossils the Lower Cretaceous sediments of East Greenland was previously dated as Aptian to Albian (Spath, 1946; Maync, 1949; Donovan, 1953, 1955, 1957). Maync (1949) reported the total exposed thickness of the ‘Aptian-Albian series’ to be more than 2000 m, whereas Surlyk (1990) noted that the Lower Cretaceous shale succession reached a cumulative thickness or 1000 m. Furthermore, Donovan (1972) reported that Hauterivian and Barremian sediments were unknown in East Greenland. Dinoflagellate cysts recorded from 40 sections throughout the region have now dated the Lower Cretaceous sequence as Barremian to Albian, and correlation of sections yields a cumulative thickness of approximately 1500m (Nøhr-Hansen, 1993).

scholarly journals Triassic lithostratigraphy of East Greenland between Scoresby Sund and Kejser Franz Josephs Fjord

1980 ◽  
Vol 139 ◽  
pp. 1-56
Author(s):  
L.B Clemmensen
Keyword(s):  
North Sea ◽  
Depositional Environments ◽  
East Greenland ◽  
The North ◽  
The North Sea ◽  
Sea Area

The lithostratigraphic scheme currently in use for the Triassic rocks in Jameson Land and ScoresbyLand (70°25'-72°N) is revised and extended to cover areas to the north of Kong Oscars Fjord, up to Kejser Franz Josephs Fjord (73°15'N). The Triassic sediments (1000-1700 m thick) belong to the Scoresby Land Group which is divided into two subgroups (redefined) and four formations: the marine Wordie Creek, and the mainly continental Pingo Dal (redefined), Gipsdalen (redefined) and Fleming Fjord Formations. These formations are here subdivided into a total of 12 members and 4 beds. Four members (the Svinhufvuds Bjerge, Ødepas, Kolledalen and Vega Sund Members) and four beds (Gråklint, Sporfjeld, Pingel Dal and Tait Bjerg Beds) are new. Three members (the Paradigmabjerg, Solfaldsdal and Kap Seaforth Members) are redefined. The lithostratigraphic succession and the Triassic depositional environments in East Greenland are briefly discussed and compared with other Triassic sequences in the North Sea area.

scholarly journals Jurassic dinoflagellate cyst stratigraphy of Store Koldewey, North-East Greenland

2004 ◽  
Vol 5 ◽  
pp. 99-112 ◽  
Author(s):  
Stefan Piasecki ◽  
John H. Callomon ◽  
Lars Stemmerik
Keyword(s):  
Middle Jurassic ◽  
Upper Jurassic ◽  
Dinoflagellate Cysts ◽  
The South ◽  
Important Species ◽  
East Greenland ◽  
Sequence Stratigraphic ◽  
Fine Grained ◽  
North East ◽  
The North

The Jurassic of Store Koldewey comprises a Middle Jurassic succession towards the south and an Upper Jurassic succession towards the north. Both successions onlap crystalline basement and coarse sediments dominate. Three main lithostratigraphical units are recognised: the Pelion Formation, including the Spath Plateau Member, the Payer Dal Formation and the Bernbjerg Formation. Rich marine macrofaunas include Boreal ammonites and the successions are dated as Late Bathonian – Early Callovian and Late Oxfordian – Early Kimmeridgian on the basis of new collections combined with material in earlier collections. Fine-grained horizons and units have been analysed for dinoflagellate cysts and the stratigraphy of the diverse and well-preserved flora has been integrated with the Boreal ammonite stratigraphy. The dinoflagellate floras correlate with contemporaneous floras from Milne Land, Jameson Land and Hold with Hope farther to the south in East Greenland, and with Peary Land in North Greenland and Svalbard towards the north. The Middle Jurassic flora shows local variations in East Greenland whereas the Upper Jurassic flora gradually changes northwards in East Greenland. A Boreal flora occurs in Peary Land and Svalbard. The characteristic and stratigraphically important species Perisseiasphaeridium pannosum and Oligosphaeridium patulum have their northernmost occurrence on Store Koldewey, whereas Taeniophora iunctispina and Adnatosphaeridium sp. extend as far north as Peary Land. Assemblages of dinoflagellate cysts are used to characterise significant regional flooding events and extensive sequence stratigraphic units.

scholarly journals The structure of south Renland, Scoresby Sund. With special reference to the tectono-metamorphic evolution of a southern internal part of the Caledonides of East Greenland

1975 ◽  
Vol 112 ◽  
pp. 1-67
Author(s):  
B Chadwick
Keyword(s):  
Granulite Facies ◽  
Normal Faults ◽  
Mobile Belt ◽  
Minimum Thickness ◽  
East Greenland ◽  
North West ◽  
The North ◽  
South West ◽  
Igneous Activity ◽  
Group Form

Renland occupies an internal position within the southern extreme of the outcrop of the Caledonian mobile belt of East Greenland exposed between latitudes 70° and 82° N. In south-west Renland migmatised paragneisses derived from sediments comparable to the late Precambrian Lower Eleonore Bay Group form a multilayered sequence with a minimum thickness of 1500 m. The migmatites are interleaved with thick concordant sheets of garnetiferous augen granite, the formation of which may be linked with the low-pressure granulite or transitional amphibolite-granulite facies conditions attained during migmatisation of the paragneisses. These conditions persisted during the folding together of paragneisses and granites into regional structures of nappe dimensions which had a north or north-west direction of transport. Refolding of the nappes under continued high-grade conditions gave rise to structures locally coaxial with nappe axes. Reversals of facing of nappes occur in backfolds. Linear fabrics of sillimanite and biotite and prolate ellipsoidal augen of feldspar are parallel to fold axes and show that constrictional deformation dominated the later stages of the nappe phase and the refolding event. The constriction is attributed to compressing of rocks in south-west Renland between nappes advancing from the south and a rising mass of granite and basement gneisses in the north. Intrusion of concordant sheets of biotite-rich hypersthene monzonite (mangerite) followed the nappe deformation in south-east Renland. The principal sheet, which is 500 m thick, forms the rim to part of a lopolithic basin. Thinner sheets of monzonite injected into migmatites within the basin have been disrupted by further migmatisation and granitisation. Stable assemblages in pyribolite restite suggest this later event, which was restricted largely to the basin, attained conditions of hornblende-granulite facies. Open warps attributed to monzonite injection and the basin formation are superimposed on nappes west of the principal sheet. Normal faults with downthrow to east and west relate to the formation of troughs filled with Upper Palaeozoic and Mesozoic sediments in the Scoresby Sund region. The distribution of the faults suggests Renland was a horst area in Upper Palaeozoic times. Tertiary igneous activity in south Renland is represented by rare dykes of olivine dolerite and scattered plugs of pyroxenite which locally contain large blocks of host gneisses.

FLATTENED TIME SLICES—A STRATIGRAPHIC APPROACH TO 3D SEISMIC INTERPRETATION ON THE NORTH WEST SHELF OF AUSTRALIA

2003 ◽  
Vol 43 (1) ◽  
pp. 255
Author(s):  
K. Martens
Keyword(s):  
Vertical Section ◽  
Depositional Environments ◽  
Time Slice ◽  
North West ◽  
The North ◽  
Exploration Tool ◽  
Depositional Systems ◽  
Complex Channel ◽  
Structural Volume ◽  
Depositional Elements

Conventional time slices are a powerful method of integrating horizon picks and fault picks into a unified interpretation and are a handy way of viewing structures, especially in faulted areas. The limitation is that time slices are seldom useful in viewing the morphology of a horizon. A 3D cube is the present day structural volume; it retains any structure imparted on the geology after deposition. When a time slice is defined, the structural dip limits the area of the integral depositional elements that can be imaged. For example, a depositional surface developed as part of a fluvial-deltaic system is seldom one event and it cannot be easily identified and picked in a vertical section. Flattened time slices take out the regional dip and allow a complete depositional surface to be viewed.The North West Shelf of Australia and especially the Barrow Sub-basin is a particularly suitable place to apply this exploration technique. The entire sedimentary package, laid down in a variety of depositional environments, has been tilted to the northwest by an average of 3°. This strong post-depositional tilt limits the uses of conventional time slices to imaging only the diprelated features of an area. Whereas conventional time slices only make apparent the dip of the section, flattened time slices can reveal subtle and intricate stratigraphic architecture.This paper describes the seismic features of a number of depositional systems from the Barrow Sub-basin and outlines how complex channel systems can be determined by the use of the flattened time slice approach. Given the importance of stratigraphic plays in the Barrow Subbasin, the technique outlined in this paper is considered to be an important exploration tool.

LITHOSTRATIGRAPHY OF THE LOWER EROMANGA BASIN SEQUENCE IN SOUTH WEST QUEENSLAND

1987 ◽  
Vol 27 (1) ◽  
pp. 196
Author(s):  
B.H. John ◽  
C.S. Almond
Keyword(s):  
High Energy ◽  
Depositional Environments ◽  
Oil Fields ◽  
North West ◽  
The North ◽  
Investigation Area ◽  
South West ◽  
Basin Surface ◽  
Petroleum Wells ◽  
Eromanga Basin

Five fully-cored and wire-line logged stratigraphic bores have been drilled by the Queensland Department of Mines, relatively close to producing oil fields in the Eromanga Basin, south-west Queensland. Correlations between the stratigraphic bores and petroleum wells have established lithologic control in an area where lithostratigraphy is interpreted mainly from wire-line logs. The Eromanga Basin sequence below the Wallumbilla Formation has been investigated, and a uniform lithostratigraphic nomenclature has been applied; in the past, an inconsistent nomenclature system was applied in different petroleum wells.Accumulation of the Eromanga Basin sequence was initiated in the early Jurassic by major epeirogenic downwarping; in the investigation area the pre-Eromanga Basin surface consists mainly of rocks comprising the Thargomindah Shelf and the Cooper Basin. The lower Eromanga Basin sequence in the area onlaps the Thargomindah Shelf and thickens relatively uniformly to the north-west. The sequence comprises mainly Jurassic/Cretaceous terrestrial units in which vertical and lateral distribution is predominantly facies-controlled. These are uniformly overlain by the mainly paralic Cadna-owie Formation, signalling the initiation of a major Cretaceous transgression over the basin.The terrestrial sequence over most of the area comprises alternating coarser and finer-grained sedimentary rocks, reflecting major cyclical changes in the energy of the depositional environment. The Hutton Sandstone, Adori Sandstone and 'Namur Sandstone Member' of the Hooray Sandstone comprise mainly sandstone, and reflect high energy fluvial depositional environments. Lower energy fluvial and lacustrine conditions are reflected by the finer-grained sandstone, siltstone and mudstone of the Birkhead and Westbourne Formations, and 'Murta Member' of the Hooray Sandstone. Similar minor cycles are represented in the 'basal Jurassic' unit. The Algebuckina Sandstone, recognised only in the far south-west of the investigation area, comprises mainly fluvial sandstones.

THE PERSEUS FIELD, NORTH WEST SHELF, AUSTRALIA: A GIANT GAS ACCUMULATION IN A COMPLEX STRUCTURAL/STRATIGRAPHIC TRAP

1998 ◽  
Vol 38 (1) ◽  
pp. 52
Author(s):  
M.L. Taylor ◽  
N.B. Thompson ◽  
N.C. Taylor
Keyword(s):  
Lower Cretaceous ◽  
Upper Jurassic ◽  
Fault Scarp ◽  
North West ◽  
The North ◽  
Fault Block ◽  
Engineering Data ◽  
Production History ◽  
Complex Structural ◽  
Multi Disciplinary Team

The Perseus Field contains reported expectation (proven plus probable) dry gas and condensate reserves of 6.48 TCF (183 × 109 m3) and 165.7 MMBBL (26.3 × 106 m3), respectively, in a complex structural/stratigraphic trap. Gas is predominantly reservoired in Bathonian shallow marine sandstones of the Legendre Formation which subcrop the Upper Jurassic-Lower Cretaceous 'Main Unconformity' in a graben separating the Goodwyn and North Rankin horsts. The Lower Cretaceous Muderong Shale forms the main regional top seal. The Lower-Middle Jurassic Athol Formation forms the seat seal for the Perseus trap and subcrops the Main Unconformity northwest of North Rankin. The maximum gross gas column for the field is approximately 360 m. The Athol Formation and underlying Murat Siltstone also form the topseal for the small Searipple Field, which underlies Perseus.The Perseus trap is dip-closed to the northwest. A steep fault scarp forms the southern margin of the trap. Trap integrity is dependent upon fault seal along the western flank of the field, where the reservoir section is juxtaposed against Athol Formation claystones in a long narrow fault block downthrown from the Goodwyn block. At the southwestern corner of the field this fault block is absent and the Perseus reservoir is juxtaposed against Triassic reservoir section in the Goodwyn block.The NRA22 well, drilled from the North Rankin A platform, has been producing gas from the Perseus Field since mid-1991. Reservoir pressure measurements and production history data have been of immense value in the exploration and appraisal of this field, both in driving further drilling and in understanding the results. Integration of geoscientific and engineering data and expertise within a multi-disciplinary team was essential for the efficient appraisal and evaluation of the field.

Pre-basaltic sediments (Aptian–Paleocene) of the Kangerlussuaq Basin, southern East Greenland

2001 ◽  
pp. 99-106 ◽  
Author(s):  
Michael Larsen ◽  
Morten Bjerager ◽  
Tor Nedkvitne ◽  
Snorre Olaussen ◽  
Thomas Preuss
Keyword(s):  
North Atlantic ◽  
Deep Water ◽  
Sediment Supply ◽  
Basin Evolution ◽  
East Greenland ◽  
Sea Floor ◽  
North West ◽  
The North ◽  
The North Atlantic ◽  
Sea Floor Spreading

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Larsen, M., Bjerager, M., Nedkvitne, T., Olaussen, S., & Preuss, T. (2001). Pre-basaltic sediments (Aptian–Paleocene) of the Kangerlussuaq Basin, southern East Greenland. Geology of Greenland Survey Bulletin, 189, 99-106. https://doi.org/10.34194/ggub.v189.5163 _______________ The recent licensing round in the deep-water areas south-east of the Faeroe Islands has emphasised the continued interest of the oil industry in the frontier areas of the North Atlantic volcanic margins. The search for hydrocarbons is at present focused on the Cretaceous– Paleocene succession with the Paleocene deepwater play as the most promising (Lamers & Carmichael 1999). The exploration and evaluation of possible plays are almost solely based on seismic interpretation and limited log and core data from wells in the area west of the Shetlands. The Kangerlussuaq Basin in southern East Greenland (Fig. 1) provides, however, important information on basin evolution prior to and during continental break-up that finally led to active sea-floor spreading in the northern North Atlantic. In addition, palaeogeographic reconstructions locate the southern East Greenland margin only 50–100 km north-west of the present-day Faeroe Islands (Skogseid et al. 2000), suggesting the possibility of sediment supply to the offshore basins before the onset of rifting and sea-floor spreading. In this region the Lower Cretaceous – Palaeogene sedimentary succession reaches almost 1 km in thickness and comprises sediments of the Kangerdlugssuaq Group and the siliciclastic lower part of the otherwise basaltic Blosseville Group (Fig. 2). Note that the Kangerdlugssuaq Group was defined when the fjord Kangerlussuaq was known as ‘Kangerdlugssuaq’. Based on field work by the Geological Survey of Denmark and Greenland (GEUS) during summer 1995 (Larsen et al. 1996), the sedimentology, sequence stratigraphy and basin evolution of the Kangerlussuaq Basin were interpreted and compared with the deep-water offshore areas of the North Atlantic (Larsen et al. 1999a, b).

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