For hydrocarbon exploration, large volumes of data are acquired and used in physical modeling-based workflows to identify geologic features interest such as fault networks, salt bodies, or, general, elements petroleum systems. The adjoint modeling step, which transforms the into model space, subsequent interpretation can be very expensive, both terms computing resources domain-expert time. We propose implement a unique approach that bypasses these demanding steps, directly assisting...

The ground state geometries of sulfur clusters S2 to S13 have been calculated using a parameter-free density functional (DF) method, combined with molecular dynamics (MD) and simulated annealing techniques. results are in good agreement available experimental data, should provide reliable predictions where detailed measurements lacking (n=3,4,5,9). bonding trends discussed detail. MD-DF approach is particularly valuable larger clusters, there many local energy minima comparable energies.

The geometries of low-lying isomers phosphorus clusters P2 to P8 have been calculated using a density functional (DF) method, combined with molecular dynamics (MD) and simulated annealing techniques. structures vibration frequencies are in excellent agreement experiment those cases (P2, P4) where spectroscopic data available. A roof-shaped tetramer is prominent structural unit states P5, P6, P7, P8. Contrary widespread belief, the most stable isomer not cubic, but ‘‘wedge’’ or ‘‘cradle’’...

A molecular-dynamics simulation has been carried out for liquid and amorphous selenium in the temperature range 350--720 K. The used 64 atoms a constant-volume simple cubic cell, energy surfaces forces were calculated using density-functional formalism, with local-density approximation exchange-correlation energy. main focus is on microscopic atomic structure, associated short- intermediate-range ordering phenomena. Ring statistics, pair correlation functions g(r), structure factors S(Q),...

Determining the thermochemical properties of hydrocarbons (HCs) at high pressure and temperature is a key step toward understanding carbon reservoirs fluxes in deep Earth. The stability carbon-hydrogen systems depths greater than few thousand meters poorly understood extent abiogenic HCs Earth mantle remains controversial. We report ab initio molecular dynamics simulations free energy calculations aimed investigating formation higher from dissociation pure methane, presence surfaces...

Summary Initial stages of velocity model building (VMB) start off from smooth models that capture geological assumptions the subsurface region under analysis. Acceptable result successive iterations interpretation and seismic data processing. The interpreters ensure additions/ corrections made by processing are compliant with geophysical knowledge. Seismic adds to structural elements, faults one most relevant those events since they can signal reservoir boundaries or hydrocarbon traps....

The predictive simulation of molecular liquids requires models that are not only accurate, but computationally efficient enough to handle the large systems and long time scales required for reliable prediction macroscopic properties. We present a new approach systematic approximation first-principles potential energy surface (PES) using GAP (Gaussian Approximation Potential) framework. allows us create potentials at several different levels accuracy in reproducing true PES, which test level...

Large-scale deployment of carbon capture and storage (CCS) technology is imperative for mitigating greenhouse gas emissions to combat the effects climate change. One key elements success CCS selection appropriate sites store captured CO2. To achieve this goal, various factors such as plume migration, capacity, containment need be validated over long-time horizons. Flow simulators, which accurately model complex interplay buoyancy, viscous, capillary forces, are typically used modeling...

We present density functional (DF) calculations, using a pseudopotential scheme and plane waves as basis functions, for isolated molecules of the amino acids glycine alanine, small oligopeptides composed periodic (infinite) polyalanine helices. calculate relative energies geometries low-lying isomers alanine variety oligopeptide various DF formulations electron exchange correlation (LDA, PBE, BLYP, BP). Comparison is made with other theories experiment where possible. The free molecule...

We present ab initio molecular dynamics simulations for high-density hydrogen (${\mathit{r}}_{\mathit{s}}$=1.78-1.31, P\ensuremath{\approxeq}35--150 GPa). Protons are treated as classical point charges and electrons in local density functional theory. The basic structural entity this range is still the molecule but applying pressure changes ordering drastically. Molecules line up to form filaments eventually planes, where intermolecular distances become comparable ${\mathit{H}}_{2}$ bond...

We investigate the stability and structural properties of dense hydrogen-helium mixtures under planetary interior conditions (Jupiter Saturn). The excess free energy mixing $\ensuremath{\Delta}G(x)$ is determined as a function helium atomic fraction $x$ by ab initio molecular dynamics simulations in pressure range $4\ensuremath{\le}P\ensuremath{\le}24\mathrm{Mbar}$ at temperatures $T\ensuremath{\le}3000\mathrm{K}$. Energy, volume, entropic contributions are evaluated. Demixing...

Nanoparticle sintering remains a critical challenge in heterogeneous catalysis. In this work, we present unified deep potential (DP) model for Cu nanoparticles on three Al$_2$O$_3$ surfaces ($\gamma$-Al$_2$O$_3$(100), $\gamma$-Al$_2$O$_3$(110), and $\alpha$-Al$_2$O$_3$(0001)). Using DP-accelerated simulations, reveal striking facet-dependent nanoparticle stability mobility patterns across the surfaces. The diffuse several times faster $\alpha$-Al$_2$O$_3$(0001) than $\gamma$-Al$_2$O$_3$(100)...

We have performed simulations of liquid phases phosphorus using the molecular-dynamics--density-functional method. Starting from a system 26 ${\mathrm{P}}_{4}$ tetrahedra in simple cubic unit cell constant volume, we determine radial, angular, and defect distribution functions for molecular polymeric high temperature red P. Comparison with available experimental data earlier calculations shows that structures amorphous are very similar. The polymerization is complex process may be viewed as...

The unified method for molecular dynamics and density functional theory (MD/DF) introduced by Car Parrinello is based on zero-temperature theory. We have incorporated the finite-temperature extension of proposed Mermin into a consistent fictitious Lagrangian framework. Such an original MD/DF desirable two rather different reasons. First this framework provides general to treat electronic states at finite temperature or in non-equilibrium excited states. Second it can alleviate certain...

Abstract Gradient-based optimization algorithms can be very efficient in history matching problems. Since many commercial reservoir simulators do not have an adjoint formulation built in, exploring capability and applicability of derivative-free (DFO) is crucial. DFO treat the simulator as a black box generate new searching points using objective function values only. usually require more evaluations, but this obstacle overcome by exploiting parallel computing. This paper tests three...

Summary In this paper, we propose a machine–learning methodology using domain–knowledge constraints for well–data integration, prior/expert–knowledge incorporation, and sweet–spot identification. Such enables the analysis of effects main variables involved in production prediction evaluation what–if scenarios within geological zones. This will allow streamlining process data analytics machine learning better decisions, saving time, helping geologists reservoir completion engineers task...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure, bonding, and dynamics in heterocyclic sulfur-selenium molecules, SexSyR. O. Jones D. HohlCite this: J. Am. Chem. Soc. 1990, 112, 7, 2590–2596Publication Date (Print):March 1, 1990Publication History Published online1 May 2002Published inissue 1 March 1990https://pubs.acs.org/doi/10.1021/ja00163a018https://doi.org/10.1021/ja00163a018research-articleACS PublicationsRequest reuse permissionsArticle Views256Altmetric-Citations39LEARN ABOUT...

Gas phase He-I and He-II photoelectron (p.e.) spectra have been obtained for Ln(η-C5Me5)2, where Ln = Sm, Eu, Yb, bands associated with ionization of f-electrons are identified the Sm Yb compounds; energies calculated from quasi-relativistic Xα-SW calculations in good agreement experimental values showing compounds to be highly ionic nature, but providing no orbital reason established non-parallel geometry rings.

We present an ab initio Hohenberg - Kohn Sham density functional study of structure and electrical conductivity in hot dense hydrogen. Our covers the range 0.40 1.34 ( = 1.5 1, P 24 Mbar) at temperatures T 800 3000 K. In this both a molecular atomic insulator metal transition are expected to take place. results compared with recent double-shock experiments fluid phase. observe increase order magnitude between 1. At lowest density, hydrogen is liquid below about 1100 K continuously atomizes...

Abstract Streamline models have shown great potential for the inversion of dynamic reservoir using well production data. The solution "history matching" inverse problem is greatly simplified when sensitivities are known. This applies to both single-model optimization and multi-realization stochastic sampling objective function with uncertainty evaluation. Bayesian modeling sequential Markov chain Monte Carlo (MCMC) algorithms provides a rigorous framework sampling. However, naive approach...

Summary Accurate numerical modeling of multiphase flow and transport mechanisms is essential to study varied, complex physical phenomena including in subsurface oil gas reservoirs aquifers subject CO2 sequestration. State-of-the-art complete physics-based solvers suffer from many computational challenges. High-fidelity data-driven surrogate models that solve the governing partial differential equations (PDEs) have potential optimize time solution increase confidence critical business...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT(Cyclopentadienyl)lanthanide compounds Ln(C5Me5)2 (Ln = samarium, europium, and ytterbium): photoelectron spectra molecular orbital calculationsJennifer C. Green, Detlef. Hohl, Notker. RoeschCite this: Organometallics 1987, 6, 4, 712–720Publication Date (Print):April 1, 1987Publication History Published online1 May 2002Published inissue 1 April 1987https://pubs.acs.org/doi/10.1021/om00147a006https://doi.org/10.1021/om00147a006research-articleACS...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEnergy surfaces and structure of S7OD. Hohl, R. O. Jones, Car, M. ParrinelloCite this: J. Am. Chem. Soc. 1989, 111, 3, 825–828Publication Date (Print):February 1, 1989Publication History Published online1 May 2002Published inissue 1 February 1989https://doi.org/10.1021/ja00185a006RIGHTS & PERMISSIONSArticle Views60Altmetric-Citations26LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum full text article downloads since November...