Formulation and performance test of green cement from Tanzanian silicate materials for sustainable enhancement of oil and gas wellbore integrity Nuru L. Patrick, Makungu M. Madirisha, Regina P. Mtei Chemistry Department, College of Natural and Applied Sciences, University of Dar es Salaam, Tanzania Ensuring the integrity of oil and gas wellbores critically hinges on cement binding. This paper presents findings of the untapped potential of Tanzanian silicate materials, namely, kaolin, quartz and pumice, as a feasible option for geopolymer binder, specifically tailored to enhance the structural integrity of oil and gas wellbores. Results from XRF, XRD and FTIR analyses confirmed that kaolin, modified kaolin (metakaolin), and pumice powder are composed mainly of SiO 2 and Al 2 O 3 , while quartz composed of SiO 2 . The optimization results revealed that 21% of the formulated metasilicate from quartz in a mixture of kaolin activated at 800 °C and pumice resulted in geopolymer pastes with best compressive strength of 35.94 ± 0.93 and 33.71 ± 0.37 MPa at 70 and 90 °C, respectively, after 28 days cured in brine baths (40 g/L NaCl and 40 g/L Na 2 SO 4 ). XRD results on crystallinity showed that the formulated geopolymer pastes had amorphous phases (70.73%), indicating the presence of irregular, non-repeating atomic structure. The AFM results strongly supported the presence of amorphous phases and further revealed that the geopolymer pastes have few pores and no cracks. TGA results revealed that the geopolymer pastes were thermally stable up to 900 °C. MP-AES results showed that the concentration of dissolved metal ions from the geopolymer pastes increased from 7 to 21 days of curing and remained relatively constant at 28 days. This suggests that the geopolymerization chains increased with curing time, consuming unreacted metal ions. These results concurred with compressive strength findings. The water absorption result was 0.8133%, implying that the geopolymer pastes were water-resistant. The overall results contribute to developing sustainable and eco-friendly cement options for the oil and gas industry, ensuring the integrity and longevity of wellbores. Furthermore, these findings are in line with the 2030 Agenda for Sustainable Development, emphasizing the crucial role of green chemistry principles in addressing climate change and their potential to advance Sustainable Development Goals 9, 11, 12 and 13.
P08
© The Author(s), 2023
Made with FlippingBook Learn more on our blog