Behaviour of a cementing hydraulic binder under severe geothermal conditions

• Published in: Geothermics 1988, Vol.17 (5), p.785-813
• Main Authors: Berra, M., Fabbri, F., Facoetti, M., Noris, A., Pezzuoli, M., Ricciardulli, R., Romano, G., Tarquini, B.
• Format: Article
• Language: English
• Subjects: Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Pollution, environment geology
• ISSN: 0375-6505; 1879-3576
• DOI: 10.1016/0375-6505(88)90038-7

The performances given by cement slurries made with Geoterm cement were studied both in the laboratory and in a geothermal environment. As regards the laboratory tests, a progressive pozzolanic-type reaction was ascertained among the binder components in the examined temperature range (20–426°C) and at fixed ages (up to 28 days). The overall physical and mechanical properties have generally resulted more than satisfactory. At the highest testing temperature (426°C), mechanical strength showed a slight decrease after six months curing, but remaining mainly higher than required by technical requirements. Slurries introduced into the bottom of a geothermal well underwent a considerable alteration owing to the very aggressive environment, when freely exposed to the circulating fluid, however they resisted better when partially protected by the mould. Under the less aggressive conditions encountered near the surface, the alteration phenomena were of little importance and the slurry performances were always satisfactory.