Banca de QUALIFICAÇÃO: EDUARDO JORGE DA CUNHA LINS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : EDUARDO JORGE DA CUNHA LINS
DATE: 19/12/2023
TIME: 10:00
LOCAL: Auditório do Laboratório de Cimentos da UFRN
TITLE:

Development of sustainable blends for use in geothermal wells

KEY WORDS:

Geothermal wells, high temperature, blend, rice husk ash, silica flour

PAGES: 60
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Materiais Conjugados Não-Metálicos
SUMMARY:

The cementing process is a fundamental stage in the construction of a geothermal well. Its importance ranges from factors such as mechanical stability, such as the support of liners and rock formations, to the hydraulic isolation of the different drilled intervals, restricting the movement of fluids between the formations. Among the materials most commonly used in geothermal wells are blends containing Portland cement and silica flour. This mixture is used to control retrogression, a process which consists of reducing the compressive strength of cement pastes when subjected to high temperatures, common in geothermal wells, which can easily reach 300 °C. Rice husk ash (RHA) is a sustainable source of silica that has been widely applied as a partial replacement for cement as an alternative to crystalline silica. The aim of this work was to develop cement blends with varying proportions of silica flour and RHA for use in geothermal wells. The pastes were subjected to 300 °C and 2000 psi for 7, 14 and 28 days. After this period, compressive strength tests and physical-chemical characterizations were carried out using scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Increasing the concentration of RHA in the blends increased the mechanical strength by up to 4X when compared to the reference paste (water and cement only), as well as proving to be mechanically superior when compared to blends containing only silica flour, showing that the interaction between silica flour and CCA produces promising results in the geothermal well scenario. It was also noted that this interaction formed a denser microstructure in addition to maintaining the microstructures characteristic of cementitious materials subjected to high temperatures, which may explain why there was an increase in compressive strength in the blends containing CCA in their composition. Based on the above, blends containing CCA and SF are a sustainable alternative for application in geothermal well scenarios.

COMMITTEE MEMBERS:
Interno - 1298936 - ANTONIO EDUARDO MARTINELLI
Externo ao Programa - 1804366 - JÚLIO CÉZAR DE OLIVEIRA FREITAS - UFRNExterno ao Programa - 1995142 - RODRIGO CESAR SANTIAGO - UFRN