A combined study of the performance and hydration of a Class G oil-well cement derived from Greek raw materials

• Published in: Construction & building materials 2019-02, Vol.197, p.63-71
• Main Authors: Velissariou, D., Katsiotis, N., Tsakiridis, P., Katsiotis, M., Pistofidis, N., Kolovos, K., Beazi, M.
• Format: Article
• Language: English
• Subjects: Analysis; Cements (Building materials); Compressive strength; Forecasts and trends; Free-fluid; Hydration; Oil well cementing; Oil wells; Oil-well cement; Raw materials; Raw materials exploitation; Thickening time
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2018.11.168

•The key parameters for Class G oil cement design are C3A and alkali content.•The sulphates’ concentration poses an regulating factor concerning ettringite formation.•The Blaine air permeability is key for adjusting and controlling the thickening time.•The laboratory produced oil-well cement fully satisfies API 10A Class G requirements. Common construction materials cannot guarantee the integrity of an oil-well where high pressure & high temperature conditions exist. Proper well-cementing ensures its productive life with the used cement-slurry consisting mainly of proper cement (conforming to the American Petroleum Institute specifications). A potential market for oil well cements is expected to grow in the next decade as a consequence of the recent oil and gas findings in the NW and SE Greek Mediterranean region, triggering attraction of financial investment in the energy sector and a necessity for developing production of oil well cements deriving from Greek raw materials. In this research, the key parameters for the development (design & production) as well as characterization of an API Class G oil-well cement are investigated. Initially, the suitable raw materials were selected; the as-produced raw meal was burned properly and the produced clinker was studied in terms of mineralogy, microstructure and morphology. Afterwards, clinker was crushed & ground with natural gypsum (CaSO4·2H2O) and the final cement's physicochemical properties were determined. Cement hydration study was performed as to identify the main hydration products (after 2, 7, 28 and 90 days of curing in atmospheric conditions) and the laboratory produced oil-well cement was characterized according to API 10A standard. Lastly, the laboratory produced oil-well cement was compared to a commercially available one.