Seismic facies analyses as aid in regional gas hydrate assessments. Part-II: Prediction of reservoir properties, gas hydrate petroleum system analysis, and Monte Carlo simulation

2013 ◽  
Vol 47 ◽  
pp. 269-290 ◽  
Author(s):  
Michael Riedel ◽  
J.-J. Bahk ◽  
H.-S. Kim ◽  
N.A. Scholz ◽  
D.G. Yoo ◽  
...  
2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Chunghun Ha ◽  
David S. Kim ◽  
SeJoon Park

ANOVA gauge repeatability and reproducibility study is the most popular tool for measurement system analysis. Two experimental designs can be applied depending on the durability of the objects. If repeated measurements are possible or sufficient homogeneous nonrepeatable samples are available, crossed design is appropriate; otherwise, nested design should be used. In this paper, we investigated the adequacy of ANOVA gauge repeatability and reproducibility study from the perspective of practitioners. We proposed a Monte Carlo simulation that is close to the realistic procedure to evaluate the adequacy of both structures. During the evaluation, we considered the average performance metrics, percentage of correct decision, histogram shape, and symmetric mean absolute percentage error for the four popular performance metrics, namely, % Study Variation, % Contribution, % Tolerance, and the number of distinct categories. The experimental results show that the nested design fails to judge the precision of the gauge while the crossed design succeeds.


Author(s):  
Alessio Abrassi ◽  
Alessandra Cuneo ◽  
David Tucker ◽  
Alberto Traverso

The analysis of different energy systems has shown various sources of variability and uncertainty; hence the necessity to quantify and take these into account is becoming more and more important. In this paper, a steady state, off-design model of a solid oxide fuel cell and turbocharger hybrid system with recuperator has been developed. Performances of such stiff systems are affected significantly by uncertainties both in component performance and operating parameters. This work started with the application of Monte Carlo Simulation method, as a reference sampling method, and then compared it with two different approximated methods. The first one is the Response Sensitivity Analysis, based on Taylor series expansion, and the latter is the Polynomial Chaos, based on a linear combination of different polynomials. These are non-intrusive methods, thus the model is treated as a black-box, with the uncertainty propagation method staying at an upper level. The work is focused on the application on highly non-linear complex systems, such as the hybrid systems, without any optimization process included. Hence, only the uncertainty propagation is considered. Uncertainties in the fuel utilization, ohmic resistance of the fuel cell, and efficiency of the recuperator are taken into account. In particular, their effects on fuel cell lifetime and some simple economic parameters are evaluated. The analysis distinguishes the specific features of each approach and identifies the strongest influencing inputs to the monitored output. Both approximated methods allow an important reduction in the number of evaluations while maintaining a good accuracy compared to Monte Carlo Simulation.


Geophysics ◽  
2012 ◽  
Vol 77 (6) ◽  
pp. O55-O63 ◽  
Author(s):  
Martin Nyamapfumba ◽  
George A. McMechan

Evidence of gas hydrate and free gas occurrences in a 3D seismic volume from the West-Central Coastal Province of the Congo Fan, offshore Angola, illustrates all the components of a complete petroleum system. Analysis and interpretation are based on the information in attributes calculated from three 3D time-migrated common-angle seismic volumes; the attributes include seismic amplitude, spectral components, dip magnitude, amplitude variation with angle, and instantaneous frequency. The source is organic-rich muds associated with late Cretaceous to early Tertiary channels, the migration paths are along growth faults, and the traps are partly defined by the gas hydrate stability zone (for the gas hydrate), partly by the bottom-simulating reflector (for the subhydrate free gas), and partly by faults (for both). The spatial distribution of free gas is further supported by the associated seismic bright spots, and also by the attenuation of high frequencies of P-waves that traverse the gas-saturated zone. Locally higher temperatures, associated with upward fluid circulation along fault zones, facilitate gas transmission through the gas hydrate and forms gas chimneys that extend to the sea floor.


Author(s):  
Ryuichi Shimizu ◽  
Ze-Jun Ding

Monte Carlo simulation has been becoming most powerful tool to describe the electron scattering in solids, leading to more comprehensive understanding of the complicated mechanism of generation of various types of signals for microbeam analysis.The present paper proposes a practical model for the Monte Carlo simulation of scattering processes of a penetrating electron and the generation of the slow secondaries in solids. The model is based on the combined use of Gryzinski’s inner-shell electron excitation function and the dielectric function for taking into account the valence electron contribution in inelastic scattering processes, while the cross-sections derived by partial wave expansion method are used for describing elastic scattering processes. An improvement of the use of this elastic scattering cross-section can be seen in the success to describe the anisotropy of angular distribution of elastically backscattered electrons from Au in low energy region, shown in Fig.l. Fig.l(a) shows the elastic cross-sections of 600 eV electron for single Au-atom, clearly indicating that the angular distribution is no more smooth as expected from Rutherford scattering formula, but has the socalled lobes appearing at the large scattering angle.


Author(s):  
D. R. Liu ◽  
S. S. Shinozaki ◽  
R. J. Baird

The epitaxially grown (GaAs)Ge thin film has been arousing much interest because it is one of metastable alloys of III-V compound semiconductors with germanium and a possible candidate in optoelectronic applications. It is important to be able to accurately determine the composition of the film, particularly whether or not the GaAs component is in stoichiometry, but x-ray energy dispersive analysis (EDS) cannot meet this need. The thickness of the film is usually about 0.5-1.5 μm. If Kα peaks are used for quantification, the accelerating voltage must be more than 10 kV in order for these peaks to be excited. Under this voltage, the generation depth of x-ray photons approaches 1 μm, as evidenced by a Monte Carlo simulation and actual x-ray intensity measurement as discussed below. If a lower voltage is used to reduce the generation depth, their L peaks have to be used. But these L peaks actually are merged as one big hump simply because the atomic numbers of these three elements are relatively small and close together, and the EDS energy resolution is limited.


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