Banca de DEFESA: NINA ROSA DOS SANTOS SILVEIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : NINA ROSA DOS SANTOS SILVEIRA
DATE: 29/05/2023
TIME: 14:00
LOCAL: Pós-Graduação Engenharia Civil
TITLE:

Numerical Thermomechanical Analysis of the Convergence of Caverns for Gas Storage in Halite Deposits

KEY WORDS:

Creep. Underground Storage. Dissolution caverns. Finite element method.

PAGES: 80
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:

The storage of gas in underground caverns is one of the activities, within the oil and gas production chain, that is little explored within the national territory. With the discovery of the pre-salt fields, its exploration potential became the object of studies in several sectors, which led to the recent publication of the "New Gas Law", Law nº 14134 of April 8, 2021, which regulates the use of salt structures with the purpose of storing the most diverse materials. Gas storage in domes or salt layers generally has a lower volume than that achieved in porous media and is much more expensive to build, its main advantage being the high number of injection and removal cycles, allowing it to meet high demands during peak consumption of natural gas. In addition, in several pre-salt wells, the oil produced has a high concentration of CO2, which is currently separated from the other fluids, reinjected into the reservoir, to increase pressure, and consequent production of the wells. The storage of gas in layers of evaporites could be an alternative destination for the surplus of this CO2 that is so harmful to our atmosphere, causing an increase in the greenhouse effect. The saline rocks are impermeable and absorb a high level of deformation without suffering ruptures, under the effect of high temperatures and pressure they even suffer a phenomenon of self-healing, recovering their tightness. From a mechanical point of view, its characteristic behavior is that of creep in which, due to its state of tension and temperature, it remains deformed for long periods of time, even keeping its temperature constant and without the occurrence of new overloads. The creep model used in this study is based on an empirical formulation that considers only the stationary creep phase. Being one of the most used in geomechanical applications, this model is known as the double deformation mechanism model or also called the simplified Norton model, presenting good results when the analyzes involve long periods of time. The numerical geomechanical analyzes were carried out with the aid of the finite element code CODE-BRIGHT (COupled DEformation BRIne Gas and Heat Transport) to evaluate the stability and deformation of the caverns. The analyzes presented in this work demonstrate the influence of temperature on the life cycle of underground caverns, built by dissolution, in halite deposits, delaying or accelerating its convergence process and consequent decrease in its volume.

COMMITTEE MEMBERS:
Presidente - 2749584 - IGOR FERNANDES GOMES
Externo à Instituição - JONATHAN DA CUNHA TEIXEIRA - UFAL
Interno - 1800053 - JOSE ANTONIO BARBOSA