Carbon dioxide reservoir

The balance between calcium carbonate production and dissolution is the major pH buffering mechanism of seawater over periods of time at least on the order of thousands of years ( ). The atmospheric carbon dioxide reservoir is less than 2 percent the size of the seawater reservoir ( ) and there is active exchange between these two reservoirs across the air-water interface. Consequently, the carbon dioxide content of the atmosphere and accumulation of calcium carbonate in the deep oceans are closely coupled. 

The simplest case is to consider the steady-state value of the oceanic-atmospheric carbon dioxide reservoir f oc that results from equating mantle outgassing to ingassing by subduction. From equation (7), the condition for steady state is bridge = CdeepThydro- Using equation (9) for ividge and equation (11) for Ti,ydro. we obtain a steady-state reservoir size of... 

Wang B, Cote AP, Furukawa H et al (2008) Colossal cages in zeoUtic imidazolate frameworks as selective carbon dioxide reservoirs. Nature 453 207-211... 

Supercritical fluid extraction (SEE) is a selective technique of sample preparation that enables the preparation of matrices by varying several physical parameters. Nowadays, it is considered to be the best replacement for many extraction technologies, such as accelerated solvent, Soxhlet solvent, microwave assisted extraction and so on. It was originally marketed as a universal extraction tool in 1988 by Isco Inc. (Lincoln, Nebraska, USA), Lee Scientific (Salt Lake City, Utah, USA) and Suprex Corp. (Pittsburgh, Pennsylvania, USA). The basic components of the SFE instmment are a carbon dioxide reservoir, a pump, an extraction vessel, an oven, a restrictor... 

Fig. 14.2 Schematic representation of a classical displacement calorimeters [69]. (a annular heater b Peltier cooling unit c inlet valve d injection tube e stirrer,/ thermistor g stirrer gland h solution outlet i inlet valve control j outlet to pipette k by-pass outlet.) and of b modified calorimeter [19] a pressure transducer b gas injection device c calorimeter d pipette e carbon dioxide reservoir tank)...

Miscible processes are aimed at recovering oil which would normally be left behind as residual oil, by using a displacing fluid which actually mixes with the oil. Because the miscible drive fluid is usually more mobile than oil, it tends to bypass the oil giving rise to a low macroscopic sweep efficiency. The method is therefore best suited to high dip reservoirs. Typical miscible drive fluids include hydrocarbon solvents, hydrocarbon gases, carbon dioxide and nitrogen. 

The most common solvent employed is carbon dioxide gas, which can be injected between water spacers, a process known as WaterAlternating Gas (WAG). In most commercial schemes the gas is recovered and reinjected, sometimes with produced reservoir gas, after heavy hydrocarbons have been removed. Other solvents include nitrogen and methane. 

The combustion. The tap T2 is closed, T3 opened and the reservoir J raised (Fig. 87), to make sure that no air has been collected at the top of the nitrometer tube a small quantity of potash is left in H when tap T3 is closed and the reservoir J then lowered again. The carbon dioxide generator is switched off and tap T2 slowly turned on until it is fully opened. 

The non-hydrocarbon constituents in natural gas vary appreciably from one gas field to another. Some of these compounds are weak acids, such as hydrogen sulfide and carbon dioxide. Others are inert, such as nitrogen, helium and argon. Some natural gas reservoirs contain enough helium for commercial production. 

Fig. 11-18 A four-box model of the global carbon cycle. Reservoir inventories are given in moles and fluxes in mol/yr. The turnover time of CO2 in each reservoir with respect to the outgoing flux is shown in brackets. (Reprinted with permission from L. Machta, The role of the oceans and biosphere in the carbon dioxide cycle, in D. Dryssen and D. Jagner (1972). "The Changing Chemistry of the Oceans," pp. 121-146, John Wiley.)...

Keeling, C. D. (1973a). The carbon dioxide cycle. Reservoir models to depict the exchange of atmospheric carbon dioxide with the oceans and land plants. In "Chemistry of the Lower Atmosphere" (S. Rasool, ed.), pp. 251-329. Plenum Press, New York. 

Pearman, G. I. and Hyson, P. (1986). Global transport and inter-reservoir exchange of carbon dioxide with particular reference to stable isotopic distributions, /. Atm. Chem. 4, 81-124. 

Another EOR approach to reducing the viscosity of oil in the reservoir is ntiscible flooding— the injection of fluids that mix with the oil under reservoir conditions. Such fluids include carbon dioxide, light hydrocarbons, and ititrogen. Supply and cost of carbon dioxide are often more favorable than for other injectants. Extensive research and field testing have established the techiucal viability of miscible flooding, and a nnmber of commercial carbon dioxide miscible flooding projects are in operation. 

R. N. Diyashev, F. M. Sattarova, K. G. Mazitov, V. M. Khusainov, K. I. Sulejmanov, G. S. Karimov, and I. R. Diyashev. Recovering oil not exploited from reservoir—by injecting alternating portions of ammonium carbonate and hydrochloric acid and displacing formed carbon dioxide with water. Patent RU 2065940-C, 1996. 

L. M. Ruzin, O. E. Pleshkova, and L. V. Konovalova. Generation of carbon dioxide during thermal steam treatment of carbonate reservoirs containing high-viscosity oil. Neft Khoz, (ll) 59-62, November 1990. 

Even for reservoirs in which asphaltene deposition was not reported previously during the primary and secondary recovery, it was reported that asphaltene deposits were found in the production tubing during carbon dioxide injection enhanced oil recovery projects (18). 

For a miscible displacement at the required reservoir conditions, carbon dioxide must exist as a dense fluid (in the range 0.5 to 0.8g/cc). Unfortunately, the viscosity of even dense CO2 is in the range of 0.03 to 0.08 cp, no more than one twentieth that of crude oil. When CO2 is used directly to displace the crude, the unfavorable viscosity ratio produces inefficient oil displacement by causing fingering of the CO2, due to frontal instability. In addition, the unfavorable mobility ratio accentuates flow non-... 

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