Navegando por Assunto "Rock-fluid interaction"

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Acesso aberto (Open Access)
Estudo das alterações petrofísicas e mineralógicas em amostras de calcita e dolomita decorrentes da interação com água carbonatada e CO2 supercrítico
(Universidade Federal do Pará, 2023-05-29) SOUZA, Felipe Pereira de; LUCAS, Cláudio Regis dos Santos; http://lattes.cnpq.br/1695226159975283; HTTPS://ORCID.ORG/0000-0001-5443-462X; AUM, Pedro Tupã Pandava; http://lattes.cnpq.br/7515419219571335; https://orcid.org/0000-0002-2339-9865
CO2 capture, utilization, and storage techniques, known by the acronym CCUS (Carbon capture, utilization, and storage), have been studied as primary tools for achieving the decarbonization targets, stipulated to slow down the rise in temperature earth average. In this context, geological storage consists of injecting CO2 into the rock formation, so that it is trapped in saline aquifers, coal deposits or oil reservoirs. CO2 injection is already carried out, for example, in the Brazilian pre-salt fields, where the oil produced has a high concentration of CO2 in its composition. It is expected that other geological structures can be used for geological carbon storage. However, the geological sites must be carefully selected, one of the key points being the geochemical stability due to the contact of CO2 with the rock formation. Thus, this project aimed to study the process of interaction of CO2 with formations of carbonate rocks, to increase the fundamental knowledge regarding the processes of rock-fluid interaction in the geological storage of CO2. The methodology included the analysis of the petrophysical properties of commercial carbonate rocks (Indiana Limestone and Silurian Dolomite) and of the dolomitic carbonate sample from the Itaituba Formation, before and after exposure to CO2 in the form of carbonated water and in the supercritical form. We also used X-ray microtomography to study the porous structure of samples at different scales. The results showed that the Indiana rock samples present distributed porosity, being essentially formed by structures predominantly composed of pallets, skeletal grains, ooids and shell fragments. The samples of Silurian Dolomite presented a structure formed by less pores, however larger and more concentrated. The rock samples from the Itaituba formation showed very low porosity and permeability. The petrophysical properties evolved after contact with CO2. Rock-fluid interaction studies will show changes in rock matrices resulting from the dissolution/or expansion process. The microtomography technique of x-ray was used in the imaging of the samples to visualize the change in the morphology of the rocks, the technique allowed the comparison of before and after CO2 attack. The DRX and FRX analyzes showed positive results regarding the mineral composition of the samples used. The results of this work will contribute to the reduction of uncertainties related to the processes and mechanisms of the geological storage of CO2.
Acesso aberto (Open Access)
Influência do transporte advectivo no processo de dissolução de rochas carbonáticas em ácido clorídrico.
(Universidade Federal do Pará, 2024-04-30) COSTA, Brenda Matos da; SILVA, Daniel; AUM, Pedro Tupã Pandava; http://lattes.cnpq.br/7515419219571335
Carbonate rock stimulation is a technique used in the petroleum industry to increase the productivity index of wells by increasing the permeability of a region close to the well. In acidification, an acid is injected into the reservoir rock. In carbonate rocks, the acid interacts with the rock to promote dissolution. The acid-rock occurrence is characterized by being essentially heterogeneous due to the different phases of the reactants. The quantification of occurrence taxa in heterogeneous systems is complex, as it involves a combination of several variables that are relevant to the manifestation of transport. The way in which acid interacts with the porous medium can be analyzed using various techniques and equipment that can help with understanding. The most common equipment is the Rotating Disk Apparatus (RDA), which consists of a reactor, which can operate different pressure and temperature ranges and different rotations. However, due to the difficulty of acquiring this type of equipment, several experiments have been reported using alternative methodologies. Thus, this work aims to study how measuring the reaction rate using different methodologies can influence the result. A comparative experimental study was conducted using three different methodologies, namely, static dissolution, dynamic dissolution, and rotating disk, to measure the impact of mineralogy, porosity, rotation speed, and pressure applied to the reaction system. The focus is to evaluate to what extent the results of the static and dynamic dissolution experiments diverge from the experiments conducted with the rotating disk, which is considered the standard for this type of analysis. In general, it was observed that increasing rotation promotes an increase in the reaction rate of 10.36% from static to dynamic at 100 RPM and 63.07% from static to dynamic at 500 RPM for Indiana limestone, a similar behavior was observed for other mineralogies. Additionally, from obtaining the diffusion coefficient in the process of dynamic dissolution and rotating disk of 3.75x10^-5 and 9.13x10^-5, respectively, for coquina samples, it was evidenced that the absence of pressure in the system hinders the mass transfer process due to the presence of CO2 (g), thus underestimating the diffusion in the carbonate – HCl system.