Banca de DEFESA: KATIA BOTELHO TORRES GALINDO DE SOUZA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : KATIA BOTELHO TORRES GALINDO DE SOUZA
DATE: 31/01/2023
TIME: 09:00
LOCAL: Programa de Pós-Graduação em Engenharia Civil
TITLE:

Experimental and Numerical Study of the Influence of the Minerals Dissolution on the Characteristics of Synthetic Carbonate Rocks with Injection of a Reactive Fluid

KEY WORDS:

Synthetic carbonate rock, Mineral dissolution, Modified edometric

PAGES: 140
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:

The dissolution processes resulting from the injection and extraction of fluids modify the physical and mechanical properties of rocks, which can generate problems that affect various engineering applications that can cause changes in the natural and built environment. The main motivation of this research was to evaluate the change in the stiffness and shear strength of synthetic carbonate rocks submitted to a reactive injection fluid. There for, it is presented laboratorial tests carried out with two types of cemented carbonatic rock artificially produced. The synthetic rocks were subjected to physical characterization tests (mineralogy, computed tomography, porosity, etc.) and mechanical characterization (Uniaxial Compressive Strength test and indirect tensile tests), before and after the dissolution process to check changes in samples. The dissolution test was performed in a modified oedometer cell, which allows measurements of horizontal displacements, where the loading and dissolution phases were performed, using water and an acid solution, to evaluate the influence of pH on their initial characteristics of the samples. From the analysis of X-ray diffraction, it was possible to observe an increase in the values of porosity and permeability in the samples, with the maximum porosity being quantified of 57.8%, due to the dissolution of minerals. During dissolution, it was observed that the horizontal stress increased linearly and the maximum volumetric strain was 12.8%, due to the loss of mass, which also reflected in the mechanical characteristics, since the samples lost about 72% of the strength after the dissolution with the acid solution. In the numerical simulation, the tool used was CODE-BRIGHT (COupled DEformation BRine Gas and Heat Transport), a finite element code developed for THMC coupled problems (term, hydro, mechanical, and chemical). The constitutive model used was the BBM (Basic Barcelona Model), based on the proposal of the chemical-elastoplastic model by Castellanza & Nova (2004), which is a model that present the plastic deformations resulting from the chemical effect, characterizing the chemical degradation. To validate the proposed model, experimental dissolution tests were simulated. The study carried out in this thesis was important to understand how the dissolution of the connections between the grains lead to changes in macro scales, such as the loss of mechanical strength causing irreversible damage to the rock.

 

COMMITTEE MEMBERS:
Externa à Instituição - ALESSANDRA LEE BARBOSA FIRMO - IFPE
Presidente - 1066974 - ANALICE FRANCA LIMA AMORIM
Externa à Instituição - FLÁVIA DE OLIVEIRA LIMA FALCÃO - PETROBRAS
Interno - 2749584 - IGOR FERNANDES GOMES
Externo à Instituição - OSVALDO JOSE CORREIA FILHO