Reservoir-consumption model

Leidy, G.R. Jenkins, R.M. "The development of fishery compartments and population rate coefficients for use in reservoir ecosystem modeling. Appendix J. Digestive efficiencies and food consumption of fish." Final Report, Agreement No. WES-76-2, USDI Fish and Wildlife Service National Reservoir Research Program, Fayetteville, AR,... 

The effectiveness of alkali flooding, and, in fact, most reservoir treatments, varies widely from formation to formation in a manner that is often difficult to predict. Quantitative techniques have been applied to model the migration and consumption of alkali as it moves through a reservoir (e.g., Bunge and Radke, 1982 Zabala et al., 1982 Dria et al., 1988). There have been fewer attempts, however, to predict the specific chemical reactions that might occur in a reservoir or the effects of the initial mineralogy of the reservoir and the composition of the flood on those reactions (Bethke et al., 1992). 

Another factor that is of great importance for the observed sulfur isotope variations of natural sulfides is whether sulfate reduction takes place in an open or closed system. An open system has an infinite reservoir of sulfate in which continuous removal from the source produces no detectable loss of material. Typical examples are the Black Sea and local oceanic deeps. In such cases, H2S is extremely depleted in " S while consumption and change in " S remain negligible for the sulfate. In a closed system, the preferential loss of the lighter isotope from the reservoir has a feedback on the isotopic composition of the unreacted source material. The changes in the " S-content of residual sulfate and of the H2S are modeled in Fig. 2.21, which shows that 5 S-values of the residual sulfate steadily increase with sulfate consumption (a linear relationship on the log-normal plot). The curve for the derivative H2S is parallel to the sulfate curve at a distance which depends on the magnitude of... 

A pilot pattern should be chosen so that the injected fluid is well controlled within the pattern. Otherwise, the fluid may be lost through directional flow channels. Then any interpretation or evaluation of the pilot performance would be difficult. When evaluation wells are drilled, cores should be taken in a closed-loop method so that reservoir conditions are maintained. These cores are used to evaluate alkaline consumption, measure relative permeabilities, and so on. Formation evaluation tests are conducted at evaluation wells. Finally, simulation models (sector models) are built to integrate all the data taken to evaluate the alkaline flooding performance. 

The simplest box model consists of one reservoir that is fed by a constant flux (Fg) (Figure 8.2). The flux out of a reservoir is the product of the mass of the substance (A/) in the reservoir and a mass transfer constant (k). Box model reservoirs are simply gigantic ideal mixed flow reactors (see Chapter 4) where there is no net generation or consumption of the substance. Over geologic time spans these reactors tend to attain a steady state so that the flux into a reservoir is matched by the flux out, which means that the rate of accumulation in the reservoir is zero and M is constant (M j). The flux out of the reservoir equals a mass transfer constant (k, yr ) times the mass of the substance in the reservoir. 

Another strategy is to increase the available Al reservoir, Cq - C. For both Fe- and Ni-base alloys, increasing the starting Al content, Cq, leads to the formation of intermetallic phases which may or may not be desirable. One way to visualize reservoir data and the implication for the lifetime model is to plot time, particularly 4. versus Al content for various Fe-Al alloys tested using 1 h cycles at 1200°C, Fig. 13.14. The use of 1 h cycles is to speed the Al consumption (scale spallation) rate. To illustrate the role of... 

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