Making devices with graphene necessarily involves making contacts metals. We use density functional theory to study how is doped by adsorption on metal substrates and find that weak bonding Al, Ag, Cu, Au, Pt, while preserving its unique electronic structure, can still shift the Fermi level respect conical point approximately 0.5 eV. At equilibrium separations, crossover from p-type n-type doping occurs for a work function of 5.4 eV, value much larger than 4.5 The numerical results in are...

Based upon the observations (i) that their in-plane lattice constants match almost perfectly and (ii) electronic structures overlap in reciprocal space for one spin direction only, we predict perfect filtering interfaces between graphite (111) fcc or (0001) hcp Ni Co. The is quite insensitive to roughness disorder. formation of a chemical bond open d-shell transition metals might complicate even prevent injection into single graphene sheet can be simply prevented by dusting Co with few...

The in-plane lattice constants of close-packed planes fcc and hcp Ni Co match that graphite almost perfectly so they share a common two-dimensional reciprocal space. Their electronic structures are such overlap in this space for one spin direction only allowing us to predict perfect filtering interfaces between (111) or (0001) Co. First-principles calculations the scattering matrix show is quite insensitive amounts interface roughness disorder which drastically influence spin-filtering...

Landauer's formula relates the conductance of a quantum wire or interface to transmission probabilities. Total probabilities are frequently calculated using Green function techniques and an expression first derived by Caroli. Alternatively, partial can be from scattering wave functions that obtained matching in region Bloch modes ideal bulk leads. An elegant technique for doing this, formulated originally Ando, is here generalized any Hamiltonian represented tight-binding form. A more...

Production of mature oil fields emits significant amount CO 2 related to circulation and handling large volumes gas water. This can be reduced either by (1) using a low-carbon energy source and/or (2) reducing the non-hydrocarbon produced/injected fluids. paper describes how improved recovery techniques designed reduce intensity (kgCO /bbl oil) production efficient use injectants. It is shown that emissions associated with injection chemicals strongly influenced water cut at start project,...

Deposition of graphene on top hexagonal boron nitride (h-BN) was very recently demonstrated while is now routinely grown Ni. Because the in-plane lattice constants graphite, h-BN, graphite-like BC2N and close-packed surfaces Co, Ni Cu match almost perfectly, it should be possible to prepare ideal interfaces between these materials which are respectively, a semimetal, insulator, semiconductor, ferromagnetic nonmagnetic metals. Using parameter-free energy minimization electronic transport...

Abstract The West Salym oil field is located in the Siberian province (Russia). Its reservoir conditions are typical for region: sandstone formation with temperatures as high 83 °C, low crude viscosities of about 2 cP, and brine salinities range 14,000-16,000 ppm. waterflooded to maintain pressure close its initial level optimize recovery. Oil production from peaked 2011 since declined increasing water cuts. expected ultimate recovery factor due waterflood, reported development plan, between...

A systematic, quantitative study of the effect interface roughness and disorder on magnetoresistance FeCo$|$vacuum$|$FeCo magnetic tunnel junctions is presented based upon parameter-free electronic structure calculations. Surface found to have a very strong spin-polarized transport while that in leads (leads consisting substitutional alloy) weaker but still sufficient suppress huge tunneling magneto-resistance (TMR) predicted for ideal systems.

Abstract The conductance of nanoscale structures can be conveniently related to their scattering properties expressed in terms transmission and reflection coefficients. Wave function matching (WFM) is a transparent technique for calculating matrices any Hamiltonian that represented tight‐binding form. A first‐principles Kohn–Sham on localized orbital basis or real space grid has such WFM based upon direct the scattering‐region wave Bloch modes ideal leads used probe region. purpose this...

Abstract Low Salinity Waterflooding (LSF) is a rapidly emerging IOR/EOR technology that improves oil recovery by lowering the injection water salinity. A membrane-based desalination process provides additional advantages such as reduction of souring, scaling and it can prevent injectivity decline. Proper screening LSF for particular field requires performing laboratory SCAL tests to (i) measure relative permeability curves enable field-scale quantification benefits modeling (ii) de-risk...

Abstract Salym Petroleum Development N.V. (SPD) is a joint venture company of Shell and Gazprom Neft. SPD operates group oil fields located in Western Siberia (Russia) which West the largest. The field mature waterflood with increasing water cuts declining production. To counter decline tertiary recovery technique called Alkaline-Surfactant-Polymer (ASP) flooding was selected. According to our earlier studies potential incremental factor due ASP injection may reach 15-20% ASP-targeted...

Abstract The current work aims to understand and characterise the parameters governing development of oil bank its propagation in viscous reservoirs under bottom aquifer drive during polymer flooding. interest scope originated from two recent trials which culminated different results terms breakthrough time. A two-dimensional numerical model, homogeneous anisotropic medium influence gravity, is deployed. subjected an infinite Carter-Tracy type uses trial's data. Various were studied...

Abstract The Nimr fields comprise a group of medium size mature oil in the Southern part Oman. This study focuses on Nimr-A and Nimr-E fields. have similar reservoir properties been commercial production since 1980 through depletion. strong regional bottom aquifer provides pressure support these combination relatively high viscosity crude (~250-700 cP at conditions) resulted rapid development water conning, limiting recovery efficiency. Therefore, polymer flooding was selected as technology...

Abstract The Marmul field is a medium-large mature oil situated in the Southern part of Oman. Due to relatively high viscosity crude (~90 cP at reservoir conditions), polymer and ASP flooding were selected as technology improve recovery beyond that waterflooding. commercial-scale has been ongoing since 2010 recently further expansions plans announced. was extensively studies through laboratory tests trials. Two trials (Pilot Phase-1A) with different formulations targeting target intervals...

Abstract Low-salinity waterflooding (LSF) has been recognized as an IOR/EOR technique for both green and brown fields in which the salinity of injected water is lowered particular reservoir properties to improve oil recovery. While providing lower or similar UTC's low projects have advantage capital operational costs compared some more expensive EOR alternatives. This work describes LSF experiments, field-scale simulation results, conceptual design surface facilities West Salym field. The...

Abstract Efficient production of heavy oil from the reservoirs with strong bottom aquifer has proven to be a challenge. While providing enough energy produce field under primary depletion, in combination unfavorable oil/water mobility contrast leads rapid development water coning thereby limiting recovery. Drilling long horizontal producing wells upper part column maximizes distance and allows relatively high rates. This slows down cone increases Even further optimization production,...

Abstract In order to design and analyze Alkaline Surfactant Polymer (ASP) pilots generate reliable ASP field forecasts a robust scalable modeling workflow for the process is required. A starting point of such carry out coreflood tests history match those using numerical models. This allows validation models generates set chemical flood parameters that can be used field-scale simulation forecasts. It well established lowering interfacial tension due maximum in-situ generated soap with...

Abstract Low Salinity Waterflooding (LSF) is a rapidly emerging IOR/EOR technology that improves oil recovery by lowering the injection water salinity. A membrane-based desalination process provides additional advantages such as reduction of souring, scaling and it can prevent injectivity decline. Proper screening LSF for particular field requires performing laboratory SCAL tests to (i) measure relative permeability curves enable field-scale quantification benefits modeling (ii) de-risk...

Abstract For more than 85 years, Petroleum Development Oman (PDO) has gained significant experience in oil production from different types of reservoirs, which Gharif is the largest clastic formation terms reserves. The bears mainly medium to heavy oil, making primary and secondary (waterflooding) recovery less efficient due unfavorable oil-water mobility ratio. This paper demonstrates that polymer flooding best technology improve sweep efficiency achieve higher at acceptable costs risks....

Abstract A significant part of PDO oil resides in the fields located South Oman. These have good reservoir rock properties, moderate temperatures, brine salinities, and medium to high viscosities with low GOR. Most are mature were waterflooded for decades; however, growing production water cuts make such recovery increasingly expensive GHG emission intensive. Polymer flooding is an optimal technology address these challenges. has embarked on trialing as early 1980s Marmul field, where today,...

This paper introduces new oil recovery mechanisms for by polymer injection in heavy reservoirs with strong bottom aquifers. Due to unfavorable mobility ratio between aquifer water and the development of sharp cones significant amount remains unswept. To overcome these issues, case demonstrated this paper, a pilot was executed three horizontal injectors, located few meters above oil/water contact. The injectivity issues resulted frequent shutdowns injectors. Interestingly, cut reversal gain...

Abstract A significant proportion of the world remaining oil reserves is residing in fractured reservoirs. Conventional recovery mechanisms may result low efficiencies such Gas injection be one few techniques, which can boost production from these resources. However, higher capillary pressures associated with matrix blocks coupled extreme hydraulic contrast between and fractures ultimate factors significantly lower than equivalent non-fractured systems. Miscible or near-miscible gas...

We study topological solitary waves (kinks and antikinks) in a nonlinear one-dimensional Klein-Gordon chain with the on-site potential of double-Morse type. This is used to describe collective proton dynamics quasi-one-dimensional networks hydrogen bonds, where plays role bond. The system supports rich variety stationary kink solutions different symmetry properties. stability bifurcation structure all these states. An exactly solvable model piecewise "parabola-constant" approximation...

Abstract In the West Salym field, a mature waterflood is ongoing with increasing water cuts and declining oil production. To counter decline tertiary recovery technique called Alkaline-Surfactant-Polymer (ASP) flooding was selected. Earlier studies indicated 15-20% potential incremental due to ASP injection. An injection/production pilot demonstrate of collect information decide on subsequent commercial projects started preflush injection in February 2016. July 2016 followed by polymer slug...