Print Email Facebook Twitter Well integrity of high temperature wells: Effect of mineralogical changes on mechanical properties of well cement Title Well integrity of high temperature wells: Effect of mineralogical changes on mechanical properties of well cement Author TerHeege, J.H. Wollenweber, J. Naumann, M. Pipilikaki, P. Vercauteren, F. Publication year 2019 Abstract Wells used for steam-assisted gravity drainage (SAGD), for cyclic steam stimulation (CSS), for hydrocarbon production in areas with anomalous high geothermal gradient, or for geothermal energy extraction all are operated in high temperature environments where maintaining long term wellbore integrity is one of the key challenges. Changes in cement mineralogy and associated mechanical properties may critically affect the integrity of high temperature wells. In this study, the relation between changes in mineralogy and mechanical properties of API class G cement with 40% silica flour was investigated by exposing samples for 1-4 weeks to temperatures of 60-420°C. The effect of mineralogical changes on mechanical properties was investigated using a combination of chemical and microstructural analysis and triaxial strength tests at confining pressures of 2-15 MPa. The combined effect of changing porosity, microstructure and strength of mineral phases determines changes in mechanical behavior, in particular the formation of stronger mineral phases with higher density affect Young’s modulus, failure strength and residual strength. Deformation of the cement is more brittle at low confining pressures and more ductile at high confining pressures with a considerable residual strength after failure and highest reduction in cement stiffness and increase in strength at temperatures of 250°C. Subject Geological Survey Netherlands2015 EnergyCementsChemical analysisGeothermal energyMechanical propertiesMineralsRock mechanicsRock pressureSilica To reference this document use: http://resolver.tudelft.nl/uuid:e3d5b284-94ac-4830-8e75-c80d2023dcac TNO identifier 869845 Publisher American Rock Mechanics Association ARMA Source 53rd U.S. Rock Mechanics/Geomechanics Symposium, 23-26 June 2019, New York City, NY, USA Document type conference paper Files To receive the publication files, please send an e-mail request to TNO Library.