scholarly journals Coupled Basin and Hydro-Mechanical Modeling of Gas Chimney Formation: The SW Barents Sea

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6345
Author(s):  
Georgy A. Peshkov ◽  
Lyudmila A. Khakimova ◽  
Elena V. Grishko ◽  
Magnus Wangen ◽  
Viktoria M. Yarushina
Keyword(s):  
Barents Sea ◽  
Initial Conditions ◽  
Fluid Flows ◽  
Propagation Speed ◽  
Sedimentary Basins ◽  
Mechanical Modeling ◽  
Propagation Process ◽  
Gas Chimney ◽  
Mechanical Models ◽  
Gas Chimneys

Gas chimneys are one of the most intriguing manifestations of the focused fluid flows in sedimentary basins. To predict natural and human-induced fluid leakage, it is essential to understand the mechanism of how fluid flow localizes into conductive chimneys and the chimney dynamics. This work predicts conditions and parameters for chimney formation in two fields in the SW Barents Sea, the Tornerose field and the Snøhvit field in the Hammerfest Basin. The work is based on two types of models, basin modeling and hydro-mechanical modeling of chimney formation. Multi-layer basin models were used to produce the initial conditions for the hydro-mechanical modeling of the relatively fast chimneys propagation process. Using hydro-mechanical models, we determined the thermal, structural, and petrophysical features of the gas chimney formation for the Tornerose field and the Snøhvit field. Our hydro-mechanical model treats the propagation of chimneys through lithological boundaries with strong contrasts. The model reproduces chimneys identified by seismic imaging without pre-defining their locations or geometry. The chimney locations were determined by the steepness of the interface between the reservoir and the caprock, the reservoir thickness, and the compaction length of the strata. We demonstrate that chimneys are highly-permeable leakage pathways. The width and propagation speed of a single chimney strongly depends on the viscosity and permeability of the rock. For the chimneys of the Snøhvit field, the predicted time of formation is about 13 to 40 years for an about 2 km high chimney.

Ice loading effects in sedimentary basins with reference to the Barents sea

1997 ◽  
Vol 14 (3) ◽  
pp. 277-338 ◽  
Author(s):  
I. Lerche ◽  
Z. Yu ◽  
B. Tørudbakken ◽  
R.O. Thomsen
Keyword(s):  
Barents Sea ◽  
Sedimentary Basins ◽  
The Barents Sea ◽  
Loading Effects

scholarly journals Maximal monotone model with delay term of convolution

2005 ◽  
Vol 2005 (4) ◽  
pp. 437-453 ◽  
Author(s):  
Claude-Henri Lamarque ◽  
Jérôme Bastien ◽  
Matthieu Holland
Keyword(s):  
Differential Equations ◽  
Degrees Of Freedom ◽  
Initial Conditions ◽  
Dynamical Behavior ◽  
Maximal Monotone ◽  
Model Description ◽  
Delay Term ◽  
Existence And Uniqueness Results ◽  
Uniqueness Results ◽  
Mechanical Models

Mechanical models are governed either by partial differential equations with boundary conditions and initial conditions (e.g., in the frame of continuum mechanics) or by ordinary differential equations (e.g., after discretization via Galerkin procedure or directly from the model description) with the initial conditions. In order to study dynamical behavior of mechanical systems with a finite number of degrees of freedom including nonsmooth terms (e.g., friction), we consider here problems governed by differential inclusions. To describe effects of particular constitutive laws, we add a delay term. In contrast to previous papers, we introduce delay via a Volterra kernel. We provide existence and uniqueness results by using an Euler implicit numerical scheme; then convergence with its order is established. A few numerical examples are given.

scholarly journals Dynamic positioning and precision of bistable gene expression boundaries through diffusion and morphogen decay

2020 ◽  
Author(s):  
Melinda Liu Perkins
Keyword(s):  
Gene Expression ◽  
Mathematical Theory ◽  
Initial Conditions ◽  
Propagation Speed ◽  
Positional Information ◽  
Future Research ◽  
Toggle Switch ◽  
Embryonic Patterning ◽  
Cell Coupling ◽  
Morphogen Gradients

1AbstractTraditional models for how morphogen gradients guide embryonic patterning fail to account for experimental observations of temporal refinement in gene expression domains. Dynamic positional information has recently emerged as a framework to address this shortcoming. Here, we explore two central aspects of dynamic positional information—the precision and placement of gene expression boundaries—in bistable genetic networks driven by morphogen gradients. First, we hypothesize that temporal morphogen decay may increase the precision of a boundary by compensating for variation in initial conditions that would otherwise lead neighboring cells with identical inputs to diverge to separate steady states. Second, we explore how diffusion of gene products may play a key role in placing gene expression boundaries. Using an existing model for Hb patterning in embryonic fruit flies, we show that diffusion permits boundaries to act as near-traveling wavefronts with local propagation speed determined by morphogen concentration. We then harness our understanding of near-traveling fronts to propose a method for achieving accurate steady-state boundary placement independent of initial conditions. Our work posits functional roles for temporally varying inputs and cell-to-cell coupling in the regulation and interpretation of dynamic positional information, illustrating that mathematical theory should serve to clarify not just our quantitative, but also our intuitive understanding of patterning processes.2Author SummaryIn many developmental systems, cells interpret spatial gradients of chemical morphogens to produce gene expression boundaries in exact positions. The simplest mathematical models for “positional information” rely on threshold detection, but such models are not robust to variations in the morphogen gradient or initial protein concentrations. Furthermore, these models fail to account for experimental results showing dynamic shifts in boundary placement and increased boundary precision over time. Here, we propose two theoretical mechanisms for enhancing boundary precision and placement using a bistable toggle switch. Distinct from existing research in “dynamic positional information”, this work posits a functional role for temporal decay in morphogen concentration and for diffusion of gene expression products, the latter of which is often omitted in quantitative models. We suggest that future research into dynamic positional information would benefit from perspectives that link local (cellular) and global (patterning) behaviors, as well as from mathematical theory that builds our intuitive understanding alongside more data-driven approaches.

scholarly journals The Value of Sustained Ocean Observations for Sea Ice Predictions in the Barents Sea

2019 ◽  
Vol 32 (20) ◽  
pp. 7017-7035 ◽  
Author(s):  
Mitchell Bushuk ◽  
Xiaosong Yang ◽  
Michael Winton ◽  
Rym Msadek ◽  
Matthew Harrison ◽  
...  
Keyword(s):  
Sea Ice ◽  
Barents Sea ◽  
Initial Conditions ◽  
Heat Budget ◽  
Heat Content ◽  
Arctic Sea Ice ◽  
Heat Fluxes ◽  
Seasonal Forecasts ◽  
Surface Heat Fluxes ◽  
The Barents Sea

ABSTRACT Dynamical prediction systems have shown potential to meet the emerging need for seasonal forecasts of regional Arctic sea ice. Observationally constrained initial conditions are a key source of skill for these predictions, but the direct influence of different observation types on prediction skill has not yet been systematically investigated. In this work, we perform a hierarchy of observing system experiments with a coupled global data assimilation and prediction system to assess the value of different classes of oceanic and atmospheric observations for seasonal sea ice predictions in the Barents Sea. We find notable skill improvements due to the inclusion of both sea surface temperature (SST) satellite observations and subsurface conductivity–temperature–depth (CTD) measurements. The SST data are found to provide the crucial source of interannual variability, whereas the CTD data primarily provide climatological and trend improvements. Analysis of the Barents Sea ocean heat budget suggests that ocean heat content anomalies in this region are driven by surface heat fluxes on seasonal time scales.

scholarly journals Tilting and Flexural Stresses in Basins Due to Glaciations—An Example from the Barents Sea

Geosciences ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 474 ◽  
Author(s):  
Ingrid F. Løtveit ◽  
Willy Fjeldskaar ◽  
Magnhild Sydnes
Keyword(s):  
Barents Sea ◽  
Sedimentary Basin ◽  
Sedimentary Basins ◽  
Hydrocarbon Migration ◽  
Petroleum Potential ◽  
Physical Conditions ◽  
The Barents Sea ◽  
Stress Changes ◽  
Loading And Unloading ◽  
Norwegian Continental Shelf

Many of the Earth’s sedimentary basins are affected by glaciations. Repeated glaciations over millions of years may have had a significant effect on the physical conditions in sedimentary basins and on basin structuring. This paper presents some of the major effects that ice sheets might have on sedimentary basins, and includes examples of quantifications of their significance. Among the most important effects are movements of the solid Earth caused by glacial loading and unloading, and the related flexural stresses. The driving factor of these movements is isostasy. Most of the production licenses on the Norwegian Continental Shelf are located inside the margin of the former Last Glacial Maximum (LGM) ice sheet. Isostatic modeling shows that sedimentary basins near the former ice margin can be tilted as much as 3 m/km which might significantly alter pathways of hydrocarbon migration. In an example from the SW Barents Sea we show that flexural stresses related to the isostatic uplift after LGM deglaciation can produce stress changes large enough to result in increased fracture-related permeability in the sedimentary basin, and lead to potential spillage of hydrocarbons out of potential reservoirs. The results demonstrate that future basin modeling should consider including the loading effect of glaciations when dealing with petroleum potential in former glaciated areas.

DETERMINING 3D SEISMIC CHARACTERISTICS OF CONDUIT SYSTEM OF CHANGCHANG SAG, QIONGDONGNAN BASIN

2020 ◽  
pp. 1-50
Author(s):  
Yufeng Li ◽  
Renhai Pu ◽  
Gongcheng Zhang ◽  
Qiang Han ◽  
Chao Yuan ◽  
...  
Keyword(s):  
High Amplitude ◽  
Water Area ◽  
Qiongdongnan Basin ◽  
3D Seismic ◽  
Weak Zone ◽  
Low Frequencies ◽  
Gas Chimney ◽  
Conduit System ◽  
Deep Water Area ◽  
Gas Chimneys

Although some giant gas fields found in the deep-water area of the Qingdongnan Basin, China, are often associated with mud diapirs and/or gas chimneys, no comprehensive 3D work has been undertaken to characterize them. We conducted 3D seismic investigation using root mean squares (RMS), coherence, and instantaneous frequency attributes to provide better understanding of the conduit systems in the Qiongdongnan Basin. The results show that the conduit system that we investigated can be separated vertically into four zones in the following order. (1) A structurally diapiric weak zone at the base, followed by (2) an injected or reinjected sandstones zone, (3) a gas chimney zone, and (4) a mud volcanic zone at the top. The morphology of the structurally weak zone is elliptical, formed by the intersection of NW–SE– and nearly E–W–trending tectonic faults. We infer that this zone provides pathways for the ascent of the diapiric mud that was probably sourced by the underlying overpressured mudstones. The injected or reinjected sandstones zone is characterized by high amplitude anomalies (HAAs), and was probably fed by the lobes of underlying submarine fans. The gas chimney zone which is characterized by low frequencies and weak amplitudes, is probably composed of a mixture of uprising mud and free gas formed from the underlying overpressured mudstones; whereas, the mud volcano which has a Christmas-tree pattern, and composed of a central crater, the southern flank of which is a mudflow, formed when the uprising mud migrating upward through faults got to the paleo sea floor. Finally, we have proposed schematic illustrations that would aid in understanding the different stages of the formation and internal architecture of this conduit system.

Models and Mechanisms

2017 ◽  
Author(s):  
Henk W. de Regt
Keyword(s):  
Final Section ◽  
Molecular Models ◽  
Mechanical Modeling ◽  
James Clerk Maxwell ◽  
Mechanical Explanation ◽  
Mechanical Models ◽  
William Thomson ◽  
Lord Kelvin

This chapter analyzes the role of mechanical modeling in nineteenth-century physics, showing how precisely mechanical models were used to enhance scientific understanding. It discusses the work and ideas of William Thomson (Lord Kelvin), James Clerk Maxwell, and Ludwig Boltzmann, who advanced explicit views on the function and status of mechanical models, in particular, on their role in providing understanding. A case study of the construction of molecular models to explain the so-called specific heat anomaly highlights the role of conceptual tools in achieving understanding and shows that intelligibility is an epistemically relevant feature of mechanical models. Next, the chapter examines Boltzmann’s Bildtheorie, an interpretation of mechanical models that he developed in response to problems and criticisms of the program of mechanical explanation, and his associated pragmatic conception of understanding. The final section discusses the limitations of mechanical models and Ernst Mach’s criticism of the mechanical program.

Energy growth of three-dimensional disturbances in plane Poiseuille flow

1991 ◽  
Vol 224 ◽  
pp. 241-260 ◽  
Author(s):  
L. Hårkan Gustavsson
Keyword(s):  
Energy Density ◽  
Poiseuille Flow ◽  
Initial Conditions ◽  
Formal Solution ◽  
Three Dimensional ◽  
Propagation Speed ◽  
Inhomogeneous Equation ◽  
Normal Velocity ◽  
Plane Poiseuille Flow ◽  
Initial Value

The development of a small three-dimensional disturbance in plane Poiseuille flow is considered. Its kinetic energy is expressed in terms of the velocity and vorticity components normal to the wall. The normal vorticity develops according to the mechanism of vortex stretching and is described by an inhomogeneous equation, where the spanwise variation of the normal velocity acts as forcing. To study specifically the effect of the forcing, the initial normal vorticity is set to zero and the energy density in the wavenumber plane, induced by the normal velocity, is determined. In particular, the response from individual (and damped) Orr–Sommerfeld modes is calculated, on the basis of a formal solution to the initial-value problem. The relevant timescale for the development of the perturbation is identified as a viscous one. Even so, the induced energy density can greatly exceed that associated with the initial normal velocity, before decay sets in. Initial conditions corresponding to the least-damped Orr–Sommerfeld mode induce the largest energy density and a maximum is obtained for structures infinitely elongated in the streamwise direction. In this limit, the asymptotic solution is derived and it shows that the spanwise wavenumbers at which the largest amplification occurs are 2.60 and 1.98, for symmetric and antisymmetric normal vorticity, respectively. The asymptotic analysis also shows that the propagation speed for induced symmetric vorticity is confined to a narrower range than that for antisymmetric vorticity. From a consideration of the neglected nonlinear terms it is found that the normal velocity component cannot be nonlinearly affected by the normal vorticity growth for structures with no streamwise dependence.

scholarly journals A Model-Based Decomposition of the Sea Ice–Atmosphere Feedback over the Barents Sea during Winter

2014 ◽  
Vol 27 (7) ◽  
pp. 2533-2544 ◽  
Author(s):  
Jessica Liptak ◽  
Courtenay Strong
Keyword(s):  
Sea Ice ◽  
Positive Feedback ◽  
Barents Sea ◽  
Initial Conditions ◽  
Surface Wind ◽  
Atmospheric Temperature ◽  
Modeling Framework ◽  
Sea Ice Concentration ◽  
Positive Feedbacks ◽  
The Barents Sea

Abstract The feedback between Barents Sea ice and the winter atmosphere was studied in a modeling framework by decomposing it into two sequential boundary forcing experiments. The Community Ice Code (CICE) model was initialized with anomalously high sea ice concentration (SIC) over the Barents Sea and forced with an atmosphere produced by positive SIC anomalies, and CICE was initialized with low Barents Sea SIC and forced with an atmosphere produced by negative SIC anomalies. Corresponding control runs were produced by exposing the same SIC initial conditions to climatological atmospheres, and the monthly mean sea ice response showed a positive feedback over the Barents Sea for both experiments: the atmosphere produced by positive SIC anomalies increased SIC over the Barents Sea during the winter, and the atmosphere produced by negative SIC anomalies decreased SIC. These positive feedbacks were driven primarily by thermodynamic forcing from surface longwave flux anomalies and were weakened somewhat by atmospheric temperature advection. Dynamical effects also opposed the positive feedback, with enhanced surface wind stress divergence over the Barents Sea in the high-SIC case and enhanced convergence in the low-SIC case.

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