Tracer chemical

As of this writing, it has not been possible to use the seismic data which defines the volume of the reservoir to also determine the joint stmcture. Extended flow testing is the most direct measure of the efficiency and sustainabiUty of energy recovery from the reservoir. The use of chemical tracers in the circulating fluid can also provide valuable supporting data with regard to the multiplicity of flow paths and the transit time of fluid within the reservoir (37). 

Some attempts have been made to use reactive hydrocarbons in conjunction with inert chemical tracers to deduce HO concentrations in urban plumes (139,140,141). Difficulties in deducing [HO ] from these experiments have been studied by McKeen et al (142), who conclude that such experiments can underpredict HO concentrations by a factor of 2 when more reactive hydrocarbons are used and parameterization of transport processes is not properly accounted for. 

Although the general circulation patterns are fairly well known, it is difficult to quantify the rates of the various flows. Abyssal circulation is generally quite slow and variable on short time scales. The calculation of the rate of formation of abyssal water is also fraught with uncertainty. Probably the most promising means of assigning the time dimension to oceanic processes is through the study of the distribution of radioactive chemical tracers. Difficulties associated with the interpretation of radioactive tracer distributions lie both in the models used, nonconservative interactions, and the difference between the time scale of the physical transport phenomenon and the mean life of the tracer. 

Keeling, C. D. and Bolin, B. (1967). The simultaneous use of chemical tracers in oceanic studies I. General theory of reservoir models. Tellus 19, 566-581. 

Liu, Y.-G., Miah, M.R.V. and Schmitt, R.A. (1988) Cerium a chemical tracer for paleooceanic redox conditions. Geochim. Cosmochim. Acta, 52, 1361-1371. 

An interwell chemical tracer study established fluid flow patterns within the pilot. Decline curve analysis showed that TFSA injection recovered more than 8150 +... 

To establish the well drainage boundaries and fluid flow patterns within the TFSA-waterflood pilot, an interwell chemical tracer study was conducted. Sodium thiocyanate was selected as the tracer on the basis of its low adsorption characteristics on reservoir rocks (36-38), its low and constant background concentration (0.9 mg/kg) in produced fluids and its ease and accuracy of analysis(39). On July 8, 1986, 500 lb (227 kg) of sodium thiocyanate dissolved in 500 gal (1.89 m3> of injection brine (76700 mg/kg of thiocyanate ion) were injected into Well TU-120. For the next five months, samples of produced fluids were obtained three times per week from each production well. The thiocyanate concentration in the produced brine samples were analyzed in duplicate by the standard ferric nitrate method(39) and in all cases, the precision of the thiocyanate determinations were within 0.3 mg/kg. The concentration of the ion in the produced brine returned to background levels when the sampling and analysis was concluded. 

TFSA-WATERFLOOD PILOT. A 36 acre (1.14 x lO m2) TFSA-waterflood pilot was recently conducted in the Torrance Field in the Los Angeles Basin of Southern California. To characterize the fluid floi patterns within the pilot, an interwell chemical tracer study was conducted with sodium thiocyanate. Results of the tracer study are shown in Table IV. Only 61.6 % of the injected tracer was recovered in the produced fluids, indicating that as much as 38.4 % of the injected fluids were flowing out of the pattern. Furthermore, since only 1604 bbl/d (255 m3/d) of brine was injected into the pattern, as much as 75.9 % of the total fluids produced by pilot wells were from outside the pattern. 

Fluid flow patterns within the pilot pattern were characterized by an interwell chemical tracer study which showed that as much as 38.4 % of the fluids injected into the pilot flowed out of the unconfined pattern and 75.9 % of the produced fluids are from outside the pattern. 

Chemical Tracers for Organic Pollutants in the Southern California Air Basin (in preparation). 

In order to provide AMS analyses to the broad ocean sciences research community, the National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS) was established at Woods Hole Oceanographic Institution (Massachusetts) in 1989. Studies performed there include identification of sources of carbon-bearing materials in the water column and sediment, dating of sedimentary samples, investigations of paleocirculation patterns (e.g., from observations of differences in 14C relative abundances in planktonic and benthic foraminifera, and coral cores and cross sections), as well as studies of modern oceanic carbon cycling and circulation. In fact, much that is known about advective and diffusive processes in the ocean comes from measurements of chemical tracers, such as 14C, rather than from direct measurements of water mass flow. 

Step 1. Leak testing is performed by adding a small amount of a special volatile chemical tracer to the contents of a tank or pipeline these chemicals are selected for their compatibility with tank and pipeline systems, as well as the lack of their presence in the environment around the tank the tracer is added at a concentration of only a few PPM, and thus has no impact on the physical properties of tank and pipeline contents. 

Residual oil combustion impact served as a test of the model s ability to predict point source emissions. Since vanadium and nickel emissions in Portland are almost totally associated with residual oil use, the CMB method was able to assign impacts with a high degree of confidence by using these two elements as chemical tracers. 

Table 24.5 Characteristic Data of Chemical Tracers Used for the Gas Exchange Experiment Nondimensional Henry s Law Constant, Ki3/vi, Molecular Diffusion Coefficient in Air, Dia, and Water, Diw, Octanol-Water Partition Coefficient, Kiow, All valid for 4°C (Data from Cirpka et al., 1993)...

Ambient HO measurements have employed both chemical tracer and direct spectroscopic approaches, the latter including both fluorescence and absorbance. The history of ambient HO measurements has been one of uneven success, as might have been expected from the attempt to develop an analytical system for an important but difficult analyte. Nevertheless, real progress has been made, and all three approaches now provide viable alternatives for providing useful ambient HO data. 

Two dynamic alternatives to the static approach have been used in HO calibration and measurement. In the CSTR (continuously stirred tank reactor) approach, air containing the tracer or tracers flows into the reactor to balance the bulk flow out to the HO measuring devices, and the contents are stirred by a fan or other means. The HO chemical tracer is measured in the inlet flow to obtain [T]() and in the outlet flow to obtain [T], Mass balance requires... 

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