Banca de DEFESA: CARLOS AUGUSTO LEAL DANTAS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : CARLOS AUGUSTO LEAL DANTAS
DATE: 28/02/2023
TIME: 15:00
LOCAL: videoconferência
TITLE:

Development of Lightweight Slurries Containing Nanosilica for Application in High-Temperature Oil Wells with Low Fracture Gradients

KEY WORDS:

Cementing; High Temperature Wells; Low Fracture Gradient; Nanosilica

PAGES: 80
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Inorgânica
SPECIALTY: Físico Química Inorgânica
SUMMARY:

The cement used in the drilling operation of high-temperature oil wells needs to be added with silica to avoid the process of retrogression of the mechanical resistance of the cementitious matrix that occurs from 110 ºC onwards, as it forms hydration products that are harmful to the cement. In wells with a low fracture gradient, it is necessary to use lightweight cement slurries to avoid the rupture of the rock formation; therefore, cement extenders are used, such as sodium bentonite. However, its use implies the reduction of the compressive strength of the cement with the increase of its concentration. In recent years, the addition of nanosilica in cement slurries has been widely studied, obtaining promising results such as an increase in rheological parameters, a reduction in porosity and permeability, and an increase in compressive strength. Hence, this work aimed to develop lightweight slurries containing nanosilica for application in high-temperature oil wells with low fracture gradients. For this, slurries with densities of 12.5, 13.0, and 13.5 lb/gal, varying the concentration of nanosilica, and standard slurries with sodium bentonite, where all slurries contained 40% crystalline silica. The slurries were assessed regarding their rheological behavior, stability, compressive strength, X-Ray Diffraction (XRD), Thermogravimetry (TGA), and Scanning Electron Microscopy (SEM). The systems considered stable were selected and subjected to curing at 41 °C and 14.7 Psi for 24 hours and for 28 days and under the condition of 180ºC and 3000 Psi for 28 days. According to the rheological findings, the concentration of nanosilica is correlated with an increase in the values of the rheological parameters. Concerning the stability and compressive strength tests, parameters were improved with increasing nanosilica concentration. Finally, nanosilica can be characterized as a water-extending additive, and its application in high-temperature oil well cementing with a low fracture gradient can be a promising alternative.

COMMITTEE MEMBERS:
Presidente - 1804366 - JÚLIO CÉZAR DE OLIVEIRA FREITAS
Interno - 1958858 - LUIZ HENRIQUE DA SILVA GASPAROTTO
Externo à Instituição - PEDRO TUPÃ PANDAVA AUM - UFPA
Externo ao Programa - 1995142 - RODRIGO CÉSAR SANTIAGO - null