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Oil Recovery (oil + recovery)
Selected AbstractsPositive-definite q -families of continuous subcell Darcy-flux CVD(MPFA) finite-volume schemes and the mixed finite element methodINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2008Michael G. Edwards Abstract A new family of locally conservative cell-centred flux-continuous schemes is presented for solving the porous media general-tensor pressure equation. A general geometry-permeability tensor approximation is introduced that is piecewise constant over the subcells of the control volumes and ensures that the local discrete general tensor is elliptic. A family of control-volume distributed subcell flux-continuous schemes are defined in terms of the quadrature parametrization q (Multigrid Methods. Birkhauser: Basel, 1993; Proceedings of the 4th European Conference on the Mathematics of Oil Recovery, Norway, June 1994; Comput. Geosci. 1998; 2:259,290), where the local position of flux continuity defines the quadrature point and each particular scheme. The subcell tensor approximation ensures that a symmetric positive-definite (SPD) discretization matrix is obtained for the base member (q=1) of the formulation. The physical-space schemes are shown to be non-symmetric for general quadrilateral cells. Conditions for discrete ellipticity of the non-symmetric schemes are derived with respect to the local symmetric part of the tensor. The relationship with the mixed finite element method is given for both the physical-space and subcell-space q -families of schemes. M -matrix monotonicity conditions for these schemes are summarized. A numerical convergence study of the schemes shows that while the physical-space schemes are the most accurate, the subcell tensor approximation reduces solution errors when compared with earlier cell-wise constant tensor schemes and that subcell tensor approximation using the control-volume face geometry yields the best SPD scheme results. A particular quadrature point is found to improve numerical convergence of the subcell schemes for the cases tested. Copyright © 2007 John Wiley & Sons, Ltd. [source] Post-harvest storage effect on quantity and quality of rose-scented geranium (Pelargonium sp. cv. ,Bourbon') oil in UttaranchalFLAVOUR AND FRAGRANCE JOURNAL, Issue 6 2005P. Ram Abstract Drying and storage of herbage for 5 days prior to distillation significantly reduced the essential oil recovery as well as oil quality. The study suggested that the geranium green biomass should be distilled afresh for better oil yield and quality in the conditions of Uttaranchal. Copyright © 2005 John Wiley & Sons, Ltd. [source] 4D technology: where are we, and where are we going?GEOPHYSICAL PROSPECTING, Issue 2 2005Rodney Calvert ABSTRACT 4D reservoir monitoring is now becoming established as a normal part of business in some companies, in some regions such as the North Sea, and for some applications, such as thermally enhanced oil recovery. Some spectacular technical successes have been reported, mostly in monitoring water floods. We are beginning to understand how to acquire and process surveys to achieve good results. There is still, however, much to improve in how we use 4D technology to capture its potential value in field management and still some way to go in the tool itself, to make it faster, cheaper and more sensitive to small production effects. [source] Numerical simulation of two-dimensional transient water driven non-Newtonian fluid flow in porous mediaINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 4 2002Zuojin Zhu Abstract Numerical simulation of two-dimensional transient water driven non-Newtonian fluid flow in porous media has been performed. The hyperbolic non-Newtonian fluid model was used to describe the characteristics of non-Newtonian fluid flow. Governing equations were first approximated by implicit finite difference, and then solved by a stabilized bi-conjugate gradient (Bi-CGSTAB) approach. A comparison of the numerical results for the case of water driven Newtonian fluid was made to validate the numerical method. For water driven Newtonian fluid flow, it was found that the numerical results are satisfactorily consistent with those obtained by commercial software VIP which is the abbreviation of vector implicit procedure for numerical simulation of Newtonian fluid flow in porous media. The maximum deviation for average pressure is less than 1.5 per cent; the distribution of water saturation is almost the same as that obtained by VIP. For water driven non-Newtonian fluid flow in porous media, it was found that the factor of pressure gradient of the non-Newtonian fluid has significant effects on the process of oil recovery. The correction of numerical simulation based on the global mass balance plays an important role in oil reservoir simulation. Copyright © 2002 John Wiley & Sons, Ltd. [source] Mixing of two binary nonequilibrium phases in one dimensionAICHE JOURNAL, Issue 8 2009Kjetil B. Haugen Abstract The mixing of nonequilibrium phases has important applications in improved oil recovery and geological CO2 -storage. The rate of mixing is often controlled by diffusion and modeling requires diffusion coefficients at subsurface temperature and pressure. High-pressure diffusion coefficients are commonly inferred from changes in bulk properties as two phases equilibrate in a PVT cell. However, models relating measured quantities to diffusion coefficients usually ignore convective mass transport. This work presents a comprehensive model of mixing of two nonequilibrium binary phases in one-dimension. Mass transport due to bulk velocity triggered by compressibility and nonideality is taken into account. Ignoring this phenomenon violates local mass balance and does not allow for changes in phase volumes. Simulations of two PVT cell experiments show that models ignoring bulk velocity may significantly overestimate the diffusion coefficients. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Effects of sand and process water pH on toluene diluted heavy oil in water emulsions in turbulent flowAICHE JOURNAL, Issue 1 2009Chandra W. Angle Abstract The presence of sand in heavy oil production is known to enhance oil recovery. Sand can also be detrimental depending on the properties of the sand,water interface. In this process, the water soluble material interacts with both sand and oil droplets and affects emulsion stability. The formation and stability of heavy oil-in-water emulsions during turbulent flow using batch process stirred-tank mixing of oil, sand, and water were investigated at three pH. Size distributions were measured by laser diffraction. High-speed video photomicrography was used to observe the process during mixing. Results showed that the presence of sand enhanced formation of stable, fine emulsion at basic pH 8.5. When the pH of the water was reduced below 6.5 both sand and droplets surface properties changed, the emulsions became less stable and coalescence was apparent. The sand grains acted as coalescers at low pH and enhanced breakage at high pH. © Her Majesty the Queen in Right of Canada, as represented by the Minister of Natural Resources, 2008 AIChE J, 2009 [source] The physical scale modelling of braided alluvial architecture and estimation of subsurface permeabilityBASIN RESEARCH, Issue 3 2002D. J. Moreton ABSTRACT The quantitative modelling of fluvial reservoirs, especially in the stages of enhanced oil recovery, requires detailed three-dimensional data at both the scale of the channel belt and within-channel. Although studies from core, analogue outcrop and modern environments may partially meet these needs, they often cannot provide detail on the smaller-scale (i.e. channel-scale) heterogeneity, frequently suffer from limited three-dimensional exposure and cannot be used to examine the influence of different variables on the process,deposit relationship. Physical modelling offers a complementary technique that can address many of these quantitative requirements and holds great future potential for integration with reservoir modelling. Physical modelling provides the potential to upscale results and derive reservoir information on three-dimensional facies geometry, connectivity and permeability. This paper describes the development and use of physical modelling, which employs generic Froude-scaling principles, in an experimental basin that permits aggradation in order to model the morphology and subsurface depositional stratigraphy of coarse-grained braided rivers. An example is presented of a 1:50 scale model based on the braided Ashburton River, Canterbury Plains, New Zealand and the adjacent late Quaternary braided alluvium exposed in the coastal cliffs. Critically, a full, bimodal grain size distribution (20% sand and 80% gravel) was used to replicate the prototype, which allows the realistic reproduction of the surface morphology and importantly permits grain size sorting during deposition. Uncertainties associated with the compression of time, sediment mass balance and the hydrodynamics of the finest particle sizes do not appear to affect the reproducibility of stratigraphy between experimental and natural environments. Sectioning of the preserved sedimentary sequence in the physical model allows quantification of the geometry, shape, spatial distribution and internal sedimentary structure of the coarse- and fine-grained facies. A six-fold facies scheme is proposed for the model braided alluvium and a direct link is established between the grain size distribution and facies type: this allows permeability to be estimated for each facies, which can be mapped onto two-dimensional vertical cross-sections of the preserved stratigraphy. Results demonstrate the dominance of four facies based on permeability that range over three orders of magnitude in hydraulic conductivity. Quantification of such variability, and linkage to both vertical proportion curves for facies distribution and connectivity presents significant advantages over other methodologies and offers great potential for the modelling of heterogeneous braided river sediments at the within channel-belt scale. This paper outlines how physical models may be used to develop high-resolution, geologically-accurate, object-based reservoir simulation models. [source] Effect of Cross Linking Agent on Alkali/Surfactant/PolymerCHINESE JOURNAL OF CHEMISTRY, Issue 1 2008Ke ZHANG Abstract Alkali/surfactant/polymer (ASP) multisystem flooding technique, which has an expansive application prospect, is one of the enhancing oil recovery (EOR) methods. By adding the organic chromium to the ASP, the molecular structure of polymer was made to change, and the capability of controlling mobility coefficient of ASP was improved. The results showed that multisystem could still keep ultra-low interfacial tension between the multisystem and crude oil after addition of Cr3+. The resistance factor and residual resistance factor, the indicator which describes the capability of controlling mobility, upgraded strikingly. However its storage modulus and loss modulus, the indicator which describes viscoelasticity, increased. The results of physical simulation experiment indicated that this type of improved ASP could increase the recovery ratio by 4.3% compared to common ASP multisystem. [source] | ||||||||||||||||