Forward Stratigraphic Modeling of Kuwait Formation, Linking Facies Architecture to Hydrocarbon Occurrence

Abstract The objective of this study is to perform forward stratigraphic modeling on the Kuwait Formation (also known as Kuwait Group) exposed stratigraphic succession along the Jal Az-Zor escarpment to explain the enigmatic occurrence of an elongated NW-SE geobody mapped from subsurface data at northern Kuwait. Outcrop measurements such as; stratigraphic successions, facies distribution, critical facies trends, and paleocurrent analysis have been collected along the 60 km length of the Jal Az-Zor escarpment. Such measurements were combined with thin section lab analysis to reveal the various sedimentary processes such as wave activity, grain size distribution, sediment supply sources, accommodation space, and erosional rates. These measurements were combined with subsurface data such as seismic attributes to reconstruct the paleography of the area and run a forward stratigraphic model simulation. The vertical succession was also utilized to reconstruct the relative sea-level fluctuation through time to develop an accurate model. Forward stratigraphic modeling resulted in building a robust and reliable facies distribution 3D model for the Jal Az-Zor escarpment that demonstrates the complex facies architecture. The model shows the various stacking patterns of several depositional sequences that are observed in the field as well as the subsurface. The enigmatic geobody mapped from seismic as a channel system in previous publications turned out to be a paleoshoreline. This shoreline is composed of high-quality sands as a result of an elevated level of wave activity. Reworking of barrier island sands was also found to be responsible for the enhanced reservoir quality. Consequently, regardless of the subsurface structure, the main driver of successful hydrocarbon accumulation is directly linked to the NW-SE trending paleoshoreline. To the best of the authors’ knowledge, this is the first time forward-stratigraphic modeling is performed along the Jal Az-Zor escarpment in north Kuwait and using such an approach to unravel Kuwait Formation heavy hydrocarbon subsurface occurrences.

Download Full-text

Stratigraphy and palaeoenvironmental interpretation of late Quaternary colluvial slope deposits in southern Africa

South African Journal of Geology ◽

10.25131/sajg.124.0031 ◽

2021 ◽

Author(s):

J. Knight

Keyword(s):

Southern Africa ◽

Land Surface ◽

Late Quaternary ◽

Ecological Factors ◽

Surface Instability ◽

Sediment Supply ◽

Spatial And Temporal Patterns ◽

Catchment Scale ◽

Accommodation Space ◽

Slope Sediment

Abstract Slope and lowland sediment systems throughout southern Africa are dominated by the presence of colluvium with interbedded palaeosols and hardground duricrusts. These sediments correspond to phases of land surface instability and stability, respectively, during the late Quaternary. This study examines the stratigraphy and environmental interpretation of slope sediment records from specific sites in southern Africa for the period of marine isotope stages (MIS) 6 to 1 (~191 ka to present), informed by theoretical ideas of the dynamics of slope systems including sediment supply and accommodation space. Based on this analysis, phases of land surface instability and stability for the period MIS 6 to 1 are identified. The spatial and temporal patterns of land surface conditions are not a simple reflection of climate forcing, but rather reflect the workings of slope systems in response to climate in addition to the role of geologic, edaphic and ecological factors that operate within catchment-scale sediment systems. Considering these systems dynamics can yield a better understanding of the usefulness and limitations of slope sediment stratigraphies.

Download Full-text

Local Finite-Amplitude Wave Activity as a Diagnostic for Rossby Wave Packets

Monthly Weather Review ◽

10.1175/mwr-d-18-0068.1 ◽

2018 ◽

Vol 146 (12) ◽

pp. 4099-4114 ◽

Cited By ~ 4

Author(s):

Paolo Ghinassi ◽

Georgios Fragkoulidis ◽

Volkmar Wirth

Keyword(s):

Rossby Wave ◽

Model Simulation ◽

Wave Packets ◽

Meridional Wind ◽

Finite Amplitude ◽

Wave Activity ◽

Amplitude Wave ◽

High Impact Weather ◽

Finite Amplitude Wave Activity ◽

Isentropic Coordinates

AbstractUpper-tropospheric Rossby wave packets (RWPs) are important dynamical features, because they are often associated with weather systems and sometimes act as precursors to high-impact weather. The present work introduces a novel diagnostic to identify RWPs and to quantify their amplitude. It is based on the local finite-amplitude wave activity (LWA) of Huang and Nakamura, which is generalized to the primitive equations in isentropic coordinates. The new diagnostic is applied to a specific episode containing large-amplitude RWPs and compared with a more traditional diagnostic based on the envelope of the meridional wind. In this case, LWA provides a more coherent picture of the RWPs and their zonal propagation. This difference in performance is demonstrated more explicitly in the framework of an idealized barotropic model simulation, where LWA is able to follow an RWP into its fully nonlinear stage, including cutoff formation and wave breaking, while the envelope diagnostic yields reduced amplitudes in such situations.

Download Full-text

The limited link between accommodation space, sediment thickness, and inner platform facies distribution (Holocene–Pleistocene, Bahamas)

The Depositional Record ◽

10.1002/dep2.50 ◽

2018 ◽

Vol 5 (3) ◽

pp. 400-420 ◽

Cited By ~ 1

Author(s):

Rieneke Weij ◽

John J. G. Reijmer ◽

Gregor P. Eberli ◽

Peter K. Swart

Keyword(s):

Sediment Thickness ◽

Facies Distribution ◽

Accommodation Space

Download Full-text

The basal unconformity of the Nanaimo Group, southwestern British Columbia: a Late Cretaceous storm-swept rocky shoreline

Canadian Journal of Earth Sciences ◽

10.1139/e06-046 ◽

2006 ◽

Vol 43 (8) ◽

pp. 1165-1181 ◽

Cited By ~ 11

Author(s):

P D Johnstone ◽

P S Mustard ◽

J A MacEachern

Keyword(s):

British Columbia ◽

Sediment Supply ◽

Storm Activity ◽

Fine Grained ◽

Accommodation Space ◽

Facies Associations ◽

Intrusive Rocks ◽

Coastal Cliffs ◽

Sandstone Facies ◽

High Sediment

The Turonian to Santonian Comox Formation forms the basal unit of the Nanaimo Group. In the southern Gulf Islands of British Columbia, the Comox Formation nonconformably overlies Devonian metavolcanic and Jurassic intrusive rocks and is interpreted to reflect a rocky foreshore reworked by waves and ultimately drowned during transgression. The nonconformity displays a relief of metres to tens of metres. Basal deposits vary in thickness, as does the facies character along the several kilometres of paleoshoreline studied. In the study area, three distinct but related environments are expressed, typical of a complex rocky shoreline with headlands and protected coves. Crudely stratified conglomerates represent gravel-dominated fans characterized by debris-flow processes, building out from local coastal cliffs and gullies directly onto the rocky shoreline. Fine-grained basal units represent shoreline environments protected from higher energy shoreline processes, presumably in small embayments. Sandstone facies associations reflect storm-dominated shoreface environments. The unusual thickness and coarseness of these shoreface intervals suggest a combination of increasing accommodation space, proximal and high sediment supply, and high frequency and energy of storm activity. This, in turn, suggests that the majority of the shoreline was exposed to the full effects of large, open-ocean storms. This interpretation differs from most previous models for the lower Nanaimo Group, which suggest that deposition occurred in more sheltered strait or bay environments.

Download Full-text

The Interaction Between Accommodation Space and Sediment Supply on Depositional Fill Patterns within the Greater Mars Basin, Deep Water Gulf of Mexico, USA: ABSTRACT

AAPG Bulletin ◽

10.1306/7834ecff-1721-11d7-8645000102c1865d ◽

1995 ◽

Vol 79 ◽

Author(s):

Michael J. Mahaffie, Robert S. Barn

Keyword(s):

Gulf Of Mexico ◽

Deep Water ◽

Sediment Supply ◽

Accommodation Space

Download Full-text

Sedapp: a non-linear diffusion-based forward stratigraphic model for shallow marine environments

10.5194/gmd-2020-256 ◽

2020 ◽

Author(s):

Jingzhe Li ◽

Piyang Liu ◽

Shuyu Sun ◽

Zhifeng Sun ◽

Yongzhang Zhou ◽

...

Keyword(s):

Sediment Supply ◽

Marine Environments ◽

Linear Diffusion ◽

Related Function ◽

Shallow Marine ◽

Stratigraphic Model ◽

Non Linear ◽

Geologic Interpretation ◽

Linear Manner ◽

Made In

Abstract. The formation of stratigraphy in shallow marine environments has long been an important topic within the geologic community. Although many advances have been made in the field of forward stratigraphic modelling (FSM), there are still some shortcomings to the existing models. In this work, the authors present our recent development and application of Sedapp: a new non-linear open-source R code for FSM. This code uses an integrated depth-distance related function as the expression of the transport coefficient to underpin the FSM with more along-shore details. In addition to conventional parameters, a negative-feedback sediment supply rate and a differentiated deposition-erosion ratio were also introduced. All parameters were implemented in a non-linear manner. Sedapp is a 3D (2DH) tool while also capable of 2D (1DH) scenarios. Two simplified case studies were conducted. The results show that Sedapp can not only assist in geologic interpretation, but is also an efficient tool for internal architecture predictions.

Download Full-text

Reply to ‘Comment on The geometry and stratigraphic position of the Maassluis Formation (western Netherlands and south-eastern North Sea)’

Netherlands Journal of Geosciences – Geologie en Mijnbouw ◽

10.1017/s0016774600022915 ◽

2005 ◽

Vol 84 (1) ◽

pp. 53-53

Author(s):

H.S.M. Jansen

Keyword(s):

North Sea ◽

Driving Forces ◽

Sediment Supply ◽

Coastal Sediments ◽

The West ◽

Sequence Stratigraphic ◽

Normal Transition ◽

Stratigraphic Model ◽

Stratigraphic Position ◽

Age Estimates

In their comment, Wesselingh et al. say that pronounced glacioeustacy renders the detailed discussions about age intervals obsolete and that they fail to see the application of the Haq curves for age estimates in the Maassluis Formation can make much sense. We would argue the following: - Eustacy and sediment supply are the driving forces behind sequence formation and configuration. As our model shows, the overall picture of the Pliocene/Pleistocene along our transect is one of an outbuilding system, going from open marine to terrestrial deposits, which is a classic sequence stratigraphic configuration.- The lower part of the Maassluis Formation in the Noordwijk borehole lies below an unconformity and consists of open marine sediments as opposed to the coastal sediments of the upper part. Since it is the normal transition over a sequence boundary, there is reason to speculate about which sequences we are looking at here and what their age is. There is a large sedimentary wedge to the west of Noordwijk that is missing in the Noordwijk borehole.- The glacial-interglacial cycles Meijer et al. (in press) refer to are likely to be better expressed in the coastal part of the formation, i.e. from ca. 2.55 Ma. This is also the part of the formation where micro-vertebrates will be found, not the (older) marine part. These cycles do not alter the overall sequence stratigraphic model, they add a climatic overprint of smaller sedimentary cycles.

Download Full-text

Linking Equatorial African precipitation to Kelvin wave processes in the CP4-Africa convection-permitting regional climate simulation

10.5194/egusphere-egu21-8419 ◽

2021 ◽

Author(s):

Godwin Ayesiga ◽

Christopher Holloway ◽

Charles Williams ◽

Gui-Ying Yang ◽

Rachel Stratton ◽

...

Keyword(s):

Observational Studies ◽

Model Simulation ◽

Wave Activity ◽

Kelvin Waves ◽

Specific Humidity ◽

Climate Simulation ◽

Kelvin Wave ◽

Low Level ◽

Equatorial Africa ◽

Precipitation Anomalies

Synoptic timescale forecasts over Equatorial Africa are important for averting weather-and climate-related disasters and the resulting agricultural losses. Observational studies have shown that rainfall anomalies often propagate eastward across Equatorial Africa, and that there is a linkage between synoptic-scale eastward-propagating precipitation and Convectively Coupled Kelvin Waves (CCKWs) over this region. We explore the mechanisms in which CCKWs modulate the propagation of precipitation from West to East over Equatorial Africa. We examine the first Africa-wide climate simulation from a convection permitting model (CP4A) along with its global driving-model simulation (G25) and evaluate both against observations (TRMM) and ERA-Interim (ERA-I), with a focus on precipitation and Kelvin wave activity.Lagged composites show that both simulations capture the eastward propagating precipitation signal seen in observational studies, though G25 has a weaker signal. Composite analysis on high-amplitude Kelvin waves further shows that both simulations capture the connection between the eastward propagating precipitation anomalies and Kelvin waves. In comparison to TRMM, however, the precipitation signal is weaker in G25, while CP4A is more realistic. As the Kelvin wave activity is also well represented in both simulations when compared to ERA-I, the weak precipitation signal in G25 may be partly associated with the weak coupling between the precipitation and Kelvin waves. We show that CCKWs modulate the eastward propagation of convection and precipitation across Equatorial Africa through at least two related physical processes. Firstly, an enhancement of the low-level westerlies leads to increased low-level convergence; secondly, westerly moisture flux anomalies amplify lower-to-mid-tropospheric specific humidity. Results show that both CP4A and G25 generally simulate the key horizontal features of CCKWs, with anomalous low-level westerlies in phase with positive precipitation anomalies. However, both models show a weakness in capturing the vertical profile of anomalous specific humidity, and the zonal-vertical circulation is too weak in G25 and incoherent in CP4A compared to ERA-I.In both ERA-I and the simulations, Kelvin wave-induced convergence and the westward tilt with height of anomalous zonal winds and specific humidity tends to weaken to the east of the East African highlands. It appears that these highlands impede the coherent eastward propagation of the wave-precipitation coupled structure.

Download Full-text