Field-scale simulations

Further refinement of the flow models from Step 3 for adaptation into field-scale simulators and development of one-and three-dimensional simulators for eventual field project design. Phenomenological determinations by high-pressure experiments of dispersion properties required of sweep control surfactant systems and selection of homologous series of surfactants (42-45). 

A field-scale simulator based on this approach would probably require simpler equations that captured the relevant phenomena without explicitly addressing many of them. Chapter 15, by Prieditis and Flumerfelt, models two-phase flow in a network of interconnected channels that consist of constricted tube segments. Work on the creation of a model that contains capillary snap-off in a network similar to that of Figure 6 has very recently been started at the University of Texas (R. Schechter, personal communication, October 26, 1987). 

One of these branches is the evolution of current pore-level flow models into computerized simulators for testing with laboratory floods in artificial and natural porous media, followed by the development and the use of field-scale simulators for designing field tests. 

This chapter will focus on the stability of foams flowing in porous media when in the presence of crude oil. Many laboratory investigations of foam-flooding have been carried out in the absence of oil, but comparatively few have been carried out in the presence of oil. For a field application, where the residual oil saturation may vary from as low as 0 to as high as 40% depending on the recovery method applied, any effect of the oil on foam stability becomes a crucial matter. The discussion in Chapter 2 showed how important the volume fraction of oil present can be to bulk foam stability. A recent field-scale simulation study of the effect of oil sensitivity on steam-foam flood performance concluded that the magnitude of the residual oil saturation was a very significant factor for the success of a full-scale steam-foam process (14). 

Sakamoto Y, Komai T., Kawamura T. et al. 2007. Field scale simulation for the effect of relative permeability on dissociation and gas production behavior during depressurization process of methane hydrate in... 

Due to the extensive research that has been conducted in the area of foam application in enhanced oil recovery, simulation of foam behaviour has become more feasible. Several methods of foam simulation have been developed population balance models [16, 17], fractional flow models [IS, 19], and models that alter the gas phase permeabilities [20, 21], Although the population balance models treat the foam generation mechanisms in a detailed fashion, they may be impractical to apply on large field scale simulations. Both the fractional flow model and the models that alter the gas phase permeabilities rely on history matching experimental data. The fractional flow model provides insight into onedimensional foam flow, but it may be more difficult to apply in three-dimensional situations. In the following section, the application of relative permeability alterations to model foam flow is investigated. 

Measurement of transport parameters The main measurement of interest under this heading is of the excluded/inaccessible pore volume (IPV) of polymer relative to tracer as parameterised by the core permeability. If this quantity is known, then it should be included in the simulation studies since it may have some effect on the relative breakthrough times of polymer and tracer. However, it has been found that the IPV effect is usually dominated by the frontal retardation of the polymer as a result of adsorption/retention, and it is not generally of major importance in the assessment of the outcome of the polymer flood. Other measurements, such as of polymer dispersion coefficient and viscous fingering parameters, are primarily of importance for interpreting detailed core flood experiments since they do not scale in a simple way to the field and cannot therefore be used directly in the polymer field-scale simulations. 

The viscosity of the live oil, water and polymer solution was 950 mPa-s, 1 mPa-s and 25 mPa-s, respectively. The relative permeability curves used to achieve the history match for the water-flood and subsequent polymer floods, are shown in Figure 3. Based on the shape of the relative permeability curves, the core is water wet, = 0.1. The water and polymer coreflood parameters were used to calibrate the field scale simulation model described in the next section. 

Thirteen oil production wells and one water injection well were used in the history match of the water injection pattern, as mapped in the areal simulation grid shown in Figure 4. The cross-section of the sand bar was modelled with the varying grid spacing. The pattern spanned 1,600 m in length and 1,000 m in width, with a maximum pay thickness of 6 m. The basic reservoir parameters used in the field-scale simulations are listed in Table 5. 

Field-scale simulations indicated that a polymer pilot initiated on a pattern with vertical wells would produce oil at much lower water cuts than the existing waterflood. 

Ken Green is a Senior Technologist for the Alberta Research Council. Ken is currently utilizing simulation programs to improve the design of polymer field applications. His work incorporates laboratory results to calibrate reservoir simulators for field-scale simulations. He has over 30 years of experience in laboratory studies for erihanced oU recovery. 

R. E. Smith, Opus An Integrated Simulation Modelfor Transport of Nonpoint-Source Pollutants at the Field Scale, Vol. I, Documentation, USDA ARS-98, U.S. Dept, of Agriculture, Washington, D.C., 1992. 

This chapter focuses on two main subjects. It will first deal with knowledge and methodologies of good practice in the study of chemical and microbial processes in wastewater collection systems. The information on such processes is provided by investigations, measurements and analyses performed at bench, pilot and field scale. Second, it is the objective to establish the theoretical basis for determination of parameters to be used for calibration and validation of sewer process models. These main objectives of the chapter are integrated sampling, pilot-scale and field measurements and laboratory studies and analyses are needed to determine wastewater characteristics, including those kinetic and stoichiometric parameters that are used in models for simulation of the site-specific sewer processes. 

Fig. 12.7 Profiles of means (a,b) and standard deviations (c,d) of the bromacil concentrations at four different time points. Solid curves denote simulated profiles obtained from the advection-dispersion equation (a,c) and the mobile-immobile model (b,d). The different symbols denote measured profiles at different times. Reprinted from Russo D, Toiber-Yasur I, Laufer A, Yaron B (1998) Numerical analysis of field scale transport of bromacil. Adv Water Resour 21 637-647. Copyright 1998 with permission of Elsevier...

IGT has developed a treatability protocol for the MGP-REM technology to determine cleanup rates and the preferred mode of treatment (landfarming, soil slurry, or in situ). The protocol consists of three phases Phase I is a feasibility test comparing a variety of techniques and is completed within 2 to 3 months phase II is a bench-scale optimization under simulated field conditions and phase III is the field-scale evaluation. 

The University of Dayton Research Institute has developed a photo-thermal detoxification unit (PDU) that can completely destroy vapor-phase organic contaminants from soil, sludge, and aqueous streams. The PDU is a patented technology that is available for licensing. Engineering plans for construction of a PDU are commercially available. The technology has not been demonstrated on a field scale but has been used in laboratory studies of simulated wastes. 

As discussed in Chapter 2, most force fields are validated based primarily on comparisons to small molecule data and moreover most comparisons involve what might be called static properties, i.e., structural or spectral data for computed fixed conformations. There are a few noteworthy exceptions the OPLS and TraPPE force fields were, at least for molecular solvents, optimized to reproduce bulk solvent properties derived from simulations, e.g., density, boiling point, and dielectric constant. In most instances, however, one is left with the question of whether force fields optimized for small molecules or molecular fragments will perform with acceptable accuracy in large-scale simulations. 

Marryott, R. A., Dougherty, D. E., and Stollar, R. L. (1993). "Optimal groundwater management - 2. Application of simulated annealing to a field-scale contamination site." Water Resour. Res., 29(4), 847-860. 

Figure 1.2 Design and development cycle for mixing-field based design there is a selection of the mixing equipment based on the process requirements. This leads to the specification of a mixing field. CFD simulations give the flow field reduced to a multi-scale mixing model.

Fig. 6. Schematic of multigrid-type hybrid simulation with two grids. At the coarse grid a macroscopic model is advanced over large length and time scales. Information is passed to the macroscopic grid/coarse model from a microscopic simulation executed on a fine grid over short length and time scales. The coarse model is advanced over macroscopic length and time scales and provides to the microscopic simulation a field for constraint fine scale simulation.

The problems of combining flow instabilities with a description of reservoir heterogeneities in a realistic unified treatment is currently of great interest for all types of EOR. Chapter 3 of this book describes the beginnings for new methods of introducing the heterogeneities of a reservoir into simulations of the fluid flow. Treatment of the fully coupled problem, i.e., flow instabilities with three fluids in a field-scale natural reservoir, will require many years of research. 

Computational methods are increasingly valuable supplements to experiments and theories in the quest to understand complex liquids. Simulations and computations can be aimed at either molecular or microstructural length scales. The most widely used molecular-scale simulation methods are molecular dynamics. Brownian dynamics, and Monte Carlo sampling. Computations can also be performed at the continuum level by numerical solutions of field equations or by Stokesian dynamics methods, described briefly below. 

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