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Diagenetic reactions, characterized by the dissolution and precipitation of minerals at low temperatures, control the quality of sedimentary rocks as hydrocarbon reservoirs. Geochemical modeling, a tool used to understand diagenetic processes, is performed through computer codes based on thermodynamic and kinetic parameters. In a comparative study, we reproduced the diagenetic reactions observed in Snorre Field reservoir sandstones, Norwegian North Sea. These reactions had been previously modeled in the literature using DISSOL-THERMAL code. In this study, we modeled the diagenetic reactions in the reservoirs using Geochemist's Workbench (GWB) and TOUGHREACT software, based on a convective-diffusive-reactive model and on the thermodynamic and kinetic parameters compiled for each reaction. TOUGHREACT and DISSOL-THERMAL modeling showed dissolution of quartz, K-feldspar and plagioclase in a similar temperature range from 25 to 80°C. In contrast, GWB modeling showed dissolution of albite, plagioclase and illite, as well as precipitation of quartz, K-feldspar and kaolinite in the same temperature range. The modeling generated by the different software for temperatures of 100, 120 and 140°C showed similarly the dissolution of quartz, K-feldspar, plagioclase and kaolinite, but differed in the precipitation of albite and illite. At temperatures of 150 and 160°C, GWB and TOUGHREACT produced different results from the DISSOL-THERMAL, except for the dissolution of quartz, plagioclase and kaolinite. The comparative study allows choosing the numerical modeling software whose results are closer to the diagenetic reactions observed in the petrographic analysis of the modeled reservoirs.KEYWORDS: dissolution; precipitation; sedimentary basins; TOUGHREACT; Geochemist's Workbench. RESUMO: Reações diagenéticas, caracterizadas pela dissolução e precipitação de minerais a baixas temperaturas, controlam a qualidade de rochas sedimentares como reservatórios de hidrocarbonetos. A modelagem geoquímica, ferramenta utilizada para compreender os processos diagenéticos, é feita através de códigos computacionais com base em parâmetros termodinâmicos e cinéticos. Em um estudo comparativo, foram reproduzidas as reações diagenéticas observadas nos arenitos-res-

The computerized geochemical modeling, a useful tool to understand the diagenetic processes influencing the quality of hydrocarbon reservoirs, is performed by using different modules of computer codes based on the thermodynamic and chemical kinetic principles and their associated parameters. As observed in the reservoir lithofacies deposited from the marine sediment-gravity flows, a case study of diagenesis is presented here from the Espírito Santo Basin in southeastern Brazil. The study uses the Geochemist's Workbench (GWB™), PHREEQC™ and TOUGHREACT™ computation packages. The comparison of performances of these packages demonstrates the convergence of results from the software-based geochemical modeling with the petrographic observation of dissolution, albitization, kaolinization, and the precipitation of calcite and dolomite. Moreover, with limited data points, e.g., the sedimentary petrographic data acquired from limited number of boreholes, the computer simulation establishes itself to be a powerful quantitative method estimating the degree and type of diagenetic alteration of turbidite reservoir bodies in contact with a source of saline-water influx associated with salt tectonics. Therefore, using the limited petrographic data points, the geochemical computer-simulation method can even be utilized and extrapolated for areas where similar geological context is interpreted but no borehole data are available. Hence, porosity of turbidite reservoir lithofacies can be predicted in relation to the spatial distribution of dissolution, kaolinization, and albitization of feldspars and authigenic carbonate precipitation.

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The corrosion of metal structures in large facilities such as AC power transmission lines results in economic losses due to the necessary replacement of these structures and the interruption of power supply. To evaluate soil corrosion of the buried part of the structure the corrosion rate of AISI1020 steel samples was determined by weight loss measurements as a function of the exposure time to the soil close to a power transmission tower. The same measurements were made with samples which were connected to the tower while buried in the soil. By comparison of the two measurement series the influence of the AC power signal on soil corrosion can be studied.

Textile dye industry causes environmental impacts due to inappropriate disposal of effluents. Several processes have been studied to effective treatment in the dye removal, one of the main molecular sieves (zeolites). The zeolite material, especially sodalite, has the ability to adsorb the metals and functional chromophore groups. Therefore, the sodalite has characteristics that have attention to the scientific community for the treatment of textile effluents. The aim of this work was to synthesize and evaluate the use of sodalite zeolite in four Si/Al ratios (1.0, 1.5, 2.0 and 2.5) and to test the adsorption capacity in the presence of violet crystal textile dye. As result, the synthesized zeolites presented a characteristic that places them in the adsorbent materials. Among the techniques used for characterization, we have the mean pore diameter between 1.65 and 2.07 nm. X-ray diffraction revealed crystalline phases as sodalite zeolite with the presence of kaolinite, mullite, and quartz. Cation-exchange-capacity was between 0.8871 to 1.017 meq/g, where it had a 14.65% increase of the 2.5-SOD sample. The dye adsorption process was reduced to 12% (44 mg/L). Thus, it has concluded that the obtained sodalite zeolites have potential in the effective removal of dyes from the textile industry.

Rice husk is considered as a waste in the rice industry but is proficient in manufacturing different materials, such as zeolites, which is produced in large quantities all over the world, for example in Brazil. Zeolite is an adsorbent support material, which can be synthesized from rice husk ash (RHA) with external sources of aluminium (ESA). The scientific community has been conducting several measures to minimize the environmental impacts caused by greenhouse gases. Several mitigation processes are presently investigated, which includes carbon dioxide injections into adsorbent materials (e.g. zeolites). The efficiency of this technology involves a zeolitic material with high crystallinity and high concentrations of SiO 2 and Al 2 O 3 (aluminosilicates). In the present work, zeolites have been synthesized from rice husk ash (SiO 2 source) and external aluminium sources (Al 2 O 3 -alumina, gibbsite and metakaolin) to fulfill that purpose. With the aid of XRF, XRD, SEM/ EDS and FTIR techniques, the zeolitic material was characterized in two distinct crystalline phases: Mordenite and ZSM-5. The synthesis was carried out by the ideal addition of ESA (2.5 g) to RHA. According to the literature, the zeolitic materials formed by the mixture of Mordenite and ZSM-5 can be availed for gas separation and greenhouse gas storage.