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... inferred to have upslope stratigraphic traps are found in a large variety of tectonic settings, including extensional, convergent, and strike-slip basins ( Figure 17A; Table 3). Extensional basins include the synrift setting of the outer Moray Firth (offshore United Kingdom central North Sea), postrift (or failed rift) settings of the central North Sea, and passive margin settings of the Campos and Espírito Santo basins (offshore Brazil) and the northeastern GOM (offshore United States). ...Similar publications
We demonstrate the possibility of suppressing the linear response of the coherent population trapping resonance frequency to variations in the external magnetic field. The suppression can be achieved at a specific value of the clock magnetic field ${\textbf{B}}$ B due to the competition between the frequency pulling by neighboring resonances and th...
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... The oil-water interface is variably inclined in reservoirs (Wells, 1988;Stenger et al., 2001;Zhang et al., 2006;Lin et al., 2007;Hou et al., 2008;Jiang et al., 2008;Sun et al., 2009;Yang et al., 2009;Huang et al., 2012;Yang and Mahmoud, 2016). In some stratigraphic traps, oil and gas accumulations often do not conform to the unified hydrodynamic relationship, do not have a unified oil-water interface, and are not distributed according to sedimentary facies and physical properties and structures (Amy, 2019). Furthermore, even in structural traps, the oil-water or gas-water interface often crosses the structural contours (Sun et al., 2009;Xue et al., 2019;Tang et al., 2021). ...
... A siliciclastic reservoir interval is a sedimentation unit composed of a mixture of sandstone and mudrock in variable proportions (Selley, 1998;Owen et al., 2017;Amy, 2019). The permeable rocks are commonly sandstone bodies. ...
... However, this sandstone assemblage includes superimposed sandstone bodies and transgressive muddy deposits between them, and the percentage of sandstones changes greatly laterally and vertically. Therefore, an "upward pinchout trap" commonly contains the pinch-out of a sedimentary facies belt (Amy, 2019), rather than simply a sandstone body. In such pinchout traps, the effective reservoir is composed of a series of permeable sandstone bodies containing several scales of lithological variations and stratigraphic architectures ( Figure 2B), which are controlled by 3-D stratigraphic stacking patterns of lithofacies (Weimer, 1966;Gustason and Ryer, 1985). ...
... Furthermore, oil and gas fields do occur in these reservoirs onshore in Taranaki Peninsula (i.e., Kaimiro, Cheal and Radnor fields). The thick prograding mudstone succession overtopping the canyons and channels acts as up-slope stratigraphic pinch-out traps for hydrocarbon accumulation in the up-dip slope direction (McCaffrey and Kneller, 2001;Amy, 2019). Moreover, the inversion structures around the Maui Field (e.g. ...
Submarine canyons, channels and gullies are conduits that transport sediments across shelf-slope margins to deep water. In South Taranaki Basin, an increase in sediment supply through the Miocene resulted in progradation and significant steepening of the slope system. Previous studies have identified numerous sediment conduits developed within this system, however their morphology and morphometric relationships with the depositional slope have not been considered. Here we apply seismic geomorphology to establish the statistical relationships between the metrics of sediment conduits at three stratigraphic intervals between which the slope gradient progressively increased. In the early-Middle Miocene, sinuous upper Moki Formation channel complexes with an average width of 1.1 km developed on a slope with an average gradient of 0.2o, routing sediment from south to north. By the late-Middle Miocene, the slope began to prograde rapidly, concurrent with a regional reorientation of the slope to the northwest, on which the lower Mount Messenger Formation canyon networks developed with a slope gradient of 0.4–1.0o. At shallow slopes of less than 0.5o, canyon morphometrics (mean width 6.6 km) are 1.8–4.7 times larger than on related upper slopes with gradients steeper than 0.5o (mean canyon width of 2.7 km). This significant shift in morphometrics occurs abruptly across the clinoform toe line. Rapid Late Miocene slope progradation resulted in the development of steep clinoform slope surfaces up to 9o, into which linear upper Mount Messenger Formation gully complexes incised. The mean gully width throughout the Middle to Late Miocene interval decreased from 1.3 km to 1.0 km as the slope gradient became steeper. This study documents how the morphology and morphometrics of sediment conduits on the South Taranaki Basin slope system changed through time in relation to changes in depositional slope gradients.
... Deepwater traps continue to be important targets for future hydrocarbon exploration and are likely to deliver future volumes in both mature and frontier basins (Amy, 2019;Collard, 2020). The several examples discussed here show that MTCs and MTDs, particularly the thicker and more extensive, may act as seals (top seals or intra-reservoir barriers) or reservoirs in deepwater petroleum systems. ...
Sediment remobilization of seafloor strata is linked to the early stages of sediment burial, diagenesis and fluid migration in different geological settings. It can impact the depositional architecture of a sedimentary basin by promoting local and widespread erosion while, in parallel, lead to an overall redistribution of near-seafloor strata (the mass movement per se). It can also generate relatively deep sediment injections, fluid-flow features and associated sediment extrusions. Sediment remobilization plays an important role in hydrocarbon-rich basins. Mass transport complexes and deposits can contain reservoirs intervals or constitute competent seal units. Sediment injections can form either reservoirs or comprise routes for fluid migration (sand injectites). Furthermore, the existence of deep hydrocarbon reservoirs is often associated with fields of mud volcanoes. This chapter highlights sediment remobilization processes as being significant due to their societal, economic and ecological impact as both geohazards and hydrocarbon indicators. While associated with hydrocarbon shows and prolific accumulations at depth, some of these processes can be also damaging to infrastructure, local populations and marine life. Finally, mass movement on continental slopes, volcanic islands or seamounts can trigger catastrophic tsunamis.
... A deeper discussion of the implications of mixed systems as reservoirs can be seen in . Recent research also highlights the role of bottom currents on stratigraphic trap development (Amy, 2019;Counts et al., 2021). The formation of moat erosions trending along-slope affects the continuity of downslope-oriented deepwater channels formed on the underlying sequence, interrupts the sand continuity and favors the formation of updip stratigraphic traps. ...
Along-slope bottom currents and a series of secondary oceanographic processes interact at different scales to form sedimentary deposits referred to as contourite and mixed (turbidite-contourite) depositional systems. The recent proliferation of both academic and industry research on deep-marine sedimentation documents significant advances in the understanding of these systems, but most nonspecialists remain unaware of the features in question and how they form. Contourites and mixed depositional systems represent a major domain of continental margin and adjacent abyssal plain sedimentation in many of the world’s oceans. They also appear in Paleozoic, Mesozoic and Cenozoic stratigraphic sections. The growing interest in these systems has led to a refined but still evolving understanding of them. In addition to resolving their exact origins and evolutionary trajectories, research must also continue to ascertain their role in deep-sea ecosystems, geological hazards, environmental policy and economic development. Key gaps in understanding persist regarding their formation, their function in oceanographic systems and their evolution over time. This chapter summarizes current conceptual paradigms for contourite and mixed depositional systems, lists global geographic examples of these systems and discusses their identification and interpretation in terms of diagnostic features as they appear in 2D and 3D seismic datasets and at sedimentary facies scale. This chapter also considers the role that bottom currents play in shaping the seafloor and controlling the sedimentary stacking patterns of deepwater sedimentary successions. The growing interest in, and implications of, contourite and mixed depositional systems demonstrates that these systems represent significant deep-marine sedimentary environments. Combined efforts of researchers, industry partners and policy-makers can help advance understanding and responsible stewardship of deepwater depositional systems.
... The notion of an interplay between submarine failure deposits and hydrocarbon accumulations is not novel among explorationists (e.g., Fairbridge, 1946). Although these deposits were historically considered as a facies to avoid from a viewpoint of hydrocarbon exploration (Posamentier and Kolla, 2003;Weimer and Slatt, 2004), it has now been recognized that MTCs and MTDs can act as source (Johnson et al., 2015;Tanavsuu-Milkeviciene and Sarg, 2012), reservoir (Bhatnagar et al., 2019;Meckel, 2011;Shanmugam et al., 2009;Welbon et al., 2007), or seal (Algar et al., 2011;Amy, 2019;Cardona et al., 2016;Godo, 2006;Kessler and Jong, 2018). Moreover, the resultant relief created by the emplacement of MTCs and MTDs can influence the pathways of post-emplacement turbidite flows (e.g., Armitage et al., 2009;Jackson et al., 2009;Kneller et al., 2016;Kremer et al., 2018;Henry et al., 2018) and creates accommodation for "healing phase" top-fill reservoir targets [e.g., Ubit field with STOIIP (stock-tank oil initially in place) ~2 billion barrels of oil (BBO), offshore Nigeria (Clayton et al., 1998); Tarn field with STOIIP ~100 MMBO and Meltwater field with STOIIP ~50 MMBO in North Slope Alaska (Houseknecht, 2019;Houseknecht and Schenk, 2007)]. ...
... A multi-scale approach is necessary to assess seal quality and identify likely seal failure mechanism(s) pre-drill (Downey, 1984(Downey, , 1994. Recent discoveries and results in producing fields demonstrate the ability of submarine failure deposits to act as effective seals for economic petroleum accumulations (Godo, 2006;Algar et al., 2011;Cardona et al., 2016;Kessler and Jong, 2018;Amy, 2019). The semi-quantitative methodology presented here can be further calibrated and made more applicable to specific basins and settings as users integrate their own information and data libraries. ...
... Deepwater traps continue to be important targets for petroleum exploration, and they are likely to deliver future volumes in both mature and frontier basins (Amy, 2019;Collard, 2020). In this work we discuss the role of deepwater deposits from submarine failures (i.e., MTCs and MTDs) in petroleum traps. ...
Mass transport complexes and their associated mass transport deposits—both referred to here as submarine failure deposits—are virtually ubiquitous in the modern and ancient sedimentary record of many deepwater basins. As exploration expands to new frontiers, submarine failure deposits are being identified as components of the petroleum system in numerous prospects. Although such deposits were historically considered facies to avoid from a viewpoint of petroleum exploration, it is now recognized that they can act as source, reservoir, or seal elements. In this paper, we set out to investigate the role of submarine failure deposits as effective seals in the petroleum system using published data and propose a methodology to risk some first-order factors at a macro-, meso-, and micro-scale that influence the seal quality of these submarine failure deposits. We accomplish this by discussing the properties intrinsic to submarine failure deposits that affect the seal quality at different scales. Based on published literature, at least six offshore fields from the Gulf of Mexico and NW Borneo are reported to have a submarine failure deposit as an effective seal. These fields combined account for ∼0.9 billion barrels of oil equivalent of cumulative discovered reserves globally and prove the potential of submarine failure deposits as effective seals and a future undervalued play concept. We use three case studies to illustrate our methodology. Our methodology can be further customized using datasets from industry and public records. The seal risk matrix presented here is based on more than a decade of research and has been already used by several exploration companies with encouraging feedback. We acknowledge the limitations of the methodology, but future interdisciplinary research and integration of new datasets and results will improve the de-risking of submarine failure deposits in exploration. Additionally, this methodology can potentially be applied to assessing seal potential of submarine failure deposits for carbon capture sequestration and storage projects.
... The Jubilee oil field, discovered in 2007, is one of a series of offshore producing deep-water fields operated by Tullow Ghana Ltd. The field, widely thought to be a stratigraphically trapped accumulation (e.g., Amy, 2019), is in fact a combined structural/stratigraphic trap with a substantial stratigraphic component (Dailly et al., 2012;Cronin, 2017). The field is currently producing approximately 70,000-80,000 bbl/day as of January 2020. ...
... Deep-water reservoir elements, including channel fill, levees, and lobes, have attracted extensive attention in academia and industry for their potential for petroleum exploration (Stow and Mayall, 2000;Pettingill and Weimer, 2002;Posamentier and Kolla, 2003). In the published literature, at least 20 fields from 11 deep-water basins globally have giant commercial discoveries include the Alba field (central North Sea), the Barracuda field (Campos Basin) and the Sea Lion field (North Falkland Basin) (Moore, 2015;Defeo de Castro, 2014;MacAulay, 2015;Amy, 2019). The channel-lobe systems in deep-water are essentially a complex formed by mutual cutting and overlapping of channels and lobes and can be divided into multiple stages responding to base level fluctuation. ...
The lithostratigraphic plays in the Dongfang area of the Yinggehai Basin at the northern margin of the South China Sea consist of a Neogene multistage, thinly bedded, channel-lobe system. Integrating high-resolution 3D seismic, lithological and well log data shows that the channel-lobe system developed primarily in the lowstand system tract of the Huangliu Formation. We investigated the developmental stages of lobes based on the stacking relationships of seismic events, the degrees of channel downcutting in lobes, and the occurrences of sandstone facies observed in the stratal slices. The lobes finally identified 9 small-scale stages, which reveal a complete sedimentary cycle controlled by high-frequency sea-level fluctuations. Facies architectures such as main channels, channels and overbank deposits were identified by using seismic sedimentology and geomorphology. Seismic stratal slices display the different characteristics of the sediment dispersal patterns in the northern part (block DF-a) and the southern region (block DF-b). The northern part contains isolated lobes. The southern region mostly contains deeply incised channels and meander belts that are wider than those in the northern part. Three main sediment dispersal patterns have been recognized, namely, channel-lobe, channelized lobe and non-channelized lobe. Sea level fluctuation and topographic variations exert strong influences on spatial-temporal evolution of the sediment diffusion and are the key controlling factors for the patterns. The methodology used in this study characterizes the submarine fan development in an area with limited well control; this methodology is more accurate for reservoir-scale exploration and development compared to other uses.
... Therefore, deconvolving the interaction between structural deformation and sedimentation is fundamental to understanding the geology of continental slopes. Structural deformation and sediment supply control important aspects of hydrocarbon plays, such as reservoir geometry and distribution, seal distribution and presence, and stratigraphic traps (Prather, 2003) (Hawie, et al., 2018) (Stirling, et al., 2018) (Amy, 2019); it is therefore vital to understand how structural deformation and sedimentation have evolved through time. ...
... Consequently deconvolving the interaction between structural deformation and sedimentation is fundamental to understanding the geology of continental slopes. Both structural deformation and sediment supply control important aspects of hydrocarbon plays, such as reservoir geometry and distribution, seal distribution and presence, and stratigraphic traps (Prather, 2003) (Hawie, et al., 2018) (Stirling, et al., 2018) (Amy, 2019); it is therefore vital to understand how structural deformation and sedimentation have evolved through time. ...
... Stratigraphic trap components such as depositional onlap or offlap edges typically carry higher risk and uncertainty, and may be harder to define, than structural components (Allan, et al., 2006), so it is important to recognize the stratal geometries of onlap and offlap, and understand how they form. Better understanding of onlap and offlap edges can assist in identifying new stratigraphic trap prospects (Amy, 2019) and ...
Deep-water depositional systems in different tectonic regimes display markedly different tectonostratigraphic evolution. The objective of this PhD was to develop a stratigraphic forward modelling program which deconvolves the controlling factors on basin fill architecture, in order to understand the dynamic interaction between structural deformation and sediment supply, using real, mapped structural geometries and stratigraphic package thicknesses. Understanding the interaction between structural deformation and sediment supply is important on active continental slopes. This interaction controls the vertical and lateral distribution of reservoir and seal lithologies, and their relation to growing structures. Subsurface prediction of trap and seal effectiveness is a vital component of CO2 sequestration or hydrocarbon exploration projects.
Onlapse-2D is a geometric-based stratigraphic forward modelling program that simulates the tectonostratigraphic evolution of mini-basins using only commonly available reflection seismic, age-dated horizon interpretations and well data, if available (not required). The resulting models efficiently simulate the stratal architecture and palaeobathymetry of the mini-basin through time. Onlapse-2D produces geologically realistic cross-sections of a range of idealized mini-basins and simulates the evolution of a mini-basin using real data in the Gulf of Mexico.
Through the modelling, I show that the development of offlap and onlap stratal terminations in structurally active mini-basins may be linked to sediment supply in some cases. However, in others the link between onlap and offlap may be weak or non-existent. Therefore, there is no requirement for the development of onlap or offlap to have a hard-wired link to extrinsic processes, such as relative sea-level change.
Simulating the tectonostratigraphic evolution of the Late Miocene within three mini-basins in the Sureste Basin of Mexico allowed me to test and develop the capacity of Onlapse-2D. This case study integrated high resolution age-dated horizons and well data with 3D-seismic horizon interpretations, and the model results revealed three phases of structural activity, which controlled the stratigraphic development in the Late Miocene. These comprise two distinct pulses of contraction-related folding, and the long-term effects of salt-withdrawal and diapirism. This case study highlights the capacity of Onlapse-2D to aid in hydrocarbon exploration, by predicting reservoir presence away from well control and by identifying candidate stratigraphic traps.
... Parker, 1986;Halsey et al., 2017); and (iv) explores predictions of the flow-power fluxbalance model for a number of different aspects of sediment transport. The results have implications for understanding the transport, erosion and deposition of particulate material by low-concentration turbidity currents, and more widely potentially for the prediction of stratigraphic architecture of basin margins, hydrocarbon reservoirs and stratigraphic traps (Amy et al., 2019), and the storage of pollutants such as microplastics (Kane & Clare, 2019;Pohl et al., 2020a) and organic carbon (Schlünz & Schneider, 2000;Galy et al., 2007;Stetten et al., 2015) in deepwater lacustrine and seafloor environments. ...
Equilibrium sediment transport is the condition of zero net entrainment and deposition by sediment-transporting flow (i.e. grade or regime). Here criteria for equilibrium sediment transport, or those used as proxies for equilibrium (for example, onset of erosion, onset of particle setting or suppression of turbulence) for dilute, suspended-load-dominated, turbidity currents, are tested against laboratory and natural data. The examined criteria are restricted to those describing flow over a bed of loose particulate material involving non-cohesive sediment. Models include both monodisperse and polydisperse formulations that represent sediment non-uniformity by using a single characteristic grain size or discretization of the grain-size distribution, respectively. Analysis shows that a polydisperse-type flux-balance model, that equates erosional and depositional fluxes and where erosion is related to the power used to lift sediment mass from the bed (the ‘Flow Power Flux Balance’ model) provides predictions most consistent with observational data. Other equilibrium models tested, monodisperse or polydisperse, fail to predict realistic bed slopes and/or flow durations for concentrations, velocities and depths within limits for natural flows. Results of the Flow Power Flux Balance model are used to quantify sediment transport fields, equilibrium Shields numbers and slopes for turbidity currents of variable flow and particle properties.
... In deepwater environments, sandbodies may become physically detached from more extensive, proximal sandy deposits, leading to updip pinchouts that have the potential to form stratigraphic traps for fluids in the subsurface. These traps are an important target for hydrocarbon exploration in many basins globally (Pettingill, 1998;Prather, 2003;Fugelli and Olsen, 2005;Biteau et al., 2014;Stirling et al., 2018;Dolson et al., 2018;Zanella and Collard, 2018;Amy, 2019). This play type offers the potential for giant world-class oil fields, making them a major focus in deepwater drilling environments where high-rate, high-ultimate-recovery reservoirs are required to satisfy economic thresholds for commercial success (Weimer and Pettingill, 2007). ...
... Outcrop data suggest relatively high net sand values for interpreted CLTZ deposits and greater lateral continuity than channel and lobe deposits (Fryer and Jobe, 2019). Thus, we suggest that CLTZ-related stratigraphic traps be considered high risk; a supposition also supported by the lack of examples of stratigraphically trapped producing reservoirs associated with CLTZ pinchouts (Amy, 2019). ...
... Known examples of fields indicate that viable traps can be produced by detachment Classes 2, 4, 5 and 6 of this study. These include reservoirs whose updip pinchouts are inferred to have been produced by turbidity current bypass (e.g., Alba, Buzzard, and Young North fields) and post-depositional erosion by submarine channels (e.g., Marlim, Marlim Sul, and Shwe fields) or mass transport erosion (e.g., Bud, Nautilus, Pabst fields) (Amy, 2019). Plays exploiting contourites have also been identified by Shanmugam et al. (1993). ...
Isolated, detached sands provide opportunities for large-volume stratigraphic traps in many deepwater petroleum systems. Here we provide a review of the different types of sandbody detachments based on published data from the modern-day seafloor and recent (generally Quaternary-present), shallow-buried strata. Detachment mechanisms can be classified based on their timing of formation relative to deposition of the detached sandbody as well as their process of formation. Syndepositional detachment mechanisms include flow transformation associated with slope failure (Class 1), turbidity current erosion (Class 2), and contourite deposition (Class 3). Post-depositional detachment is related to subsequent erosive processes and truncation of the pre-existing sandbody, either by submarine channels (Class 4), mass-transport events (Class 5), post-depositional sliding or faulting (Class 6) or bottom currents (Class 7). Examples of each of these mechanisms are identified on the modern seafloor, and show that detached sandbodies can form at different locations along the continental slope and rise (from upper slope to basin floor), and between or within different architectural elements (i.e., canyon, channels and lobes). This variation in formation style results in detached sands of highly variable sizes (tens to hundreds of kilometres) and geometries across and along the depositional profile, which are dependent upon the erosive and/or depositional processes involved, as well as the seafloor topography of the area in question. Whilst modern seafloor systems may not always represent the final stratigraphic architecture in the subsurface, they provide important insights into the development of detached sandbodies and therefore serve as potential analogues for subsurface stratigraphic traps.
