Work

Chemical Changes in the Composition of Oil Well Cement with Core/Shell Nanoparticle Addition under CO2 Geological Storage Conditions

Year: 2024

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide This work studies the influence of incorporating core/shell nanoparticles of TiO 2 covered with SiO 2 (TiO 2 @SiO 2 n TS) in oil well cement class G, evaluating chemical changes in the cement composition due to CO 2 attack. The benefits of n TS, including its self-dispersion, pozzolanic properties, and filler effects, make this nanoparticle an attractive supplementary cementitious material for oil well applications. The cement slurry mixing followed the American Petroleum Institute procedures, and no dispersive method was applied for n TS. Hardened cement pastes with water/binder ratios of 0.44 and 0.35, the last being with 0.15 wt % of polycarboxylate ether additive (PCE), were cured in an autoclave (60 °C and 40 bar) for 24 h and then submitted to degradation tests in CO 2 -saturated water at high temperature and high pressure (HTHP) (90 °C and 150 bar) during 7, 14, and 21 days. The characterization of the carbonated pastes was conducted using advanced techniques. X-ray microtomography and scanning electron microscopy showed that adding n TS and PCE significantly reduced the carbonation depth and the diffusion coefficient, with the latter decreasing by nearly an order of magnitude. Thermogravimetric and X-ray diffraction (Rietveld) analyses showed 1.32 and 1.90% higher CH amounts after carbonation in the mixtures with n TS, respectively. Moreover, in n TS’s presence, a lower content of CaCO 3 was observed. The CaCO 3 and C–S–H were characterized using solid-state nuclear magnetic resonance ( 13 C and 29 Si). Results indicated that Aragonite is the main polymorph of CaCO 3 formed, while C–S–H exhibited a lower decalcification degree when n TS was added (about 4.10% lower). Compressive strength tests of the mixtures with n TS and PCE were approximately 31.6% higher when compared with REF–PCE (without n TS). Therefore, the combined effect of n TS and PCE showed interesting properties for HTHP applications.

Source: Energy & Fuels

DOI: 10.1021/acs.energyfuels.4c03686

Authors: Giovanni dos Santos Batista, Antonio Shigueaki Takimi, Eleani Maria da Costa

Institutions: Pontifícia Universidade Católica do Rio Grande do Sul, Universidade Federal do Rio Grande do Sul

Language: English

Topic: Concrete and Cement Materials Research

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funder: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior