文档介绍:Geothermics 31 (2002) 643–656
Incorporation of fibres in geothermal well
cements
Marita L. Berndt*, Aristodimos J. Philippacopoulos
Department of Energy Sciences and Technology, Brookhaven National Laboratory, Upton, NY 11973, USA
Received 27 November 2001; accepted 13 May 2002
Abstract
Fibre-reinforced cements are of potential value in geothermal well cementing jobs due to
their ability to withstand higher tensile stresses than conventional cements. Screening tests
were performed to evaluate different fibre types with the objective of identifying systems
offering the greatest improvement in cement tensile strength. The fibres investigated included
steel, stainless steel, carbon, basalt and glass. The baseline cement matrix was standard Class
G cement/40% silica flour and variations on this were latex-modification and lightweight
formulations incorporating either perlite or microspheres. The fibres that showed the best
performance at low volume fraction were 13 mm brass-coated round steel fibres. Steel and
carbon microfibres also improved the tensile strength provided the volume fraction was high
enough. Thermal and hydraulic properties of cements reinforced with steel fibres were mea-
sured and compared with unreinforced mixes. Based on the results, selected fibre types will be
used in further property characterization studies and engineering analysis of geothermal wells
completed with fibre-reinforced materials.
# 2002 CNR. Published by Elsevier Science Ltd. All rights reserved.
Keywords: Drilling; Wells; Cement; Fibres
1. Introduction
It is essential that geothermal well cements maintain structural performance and
sealing capability throughout the lifetime of the well. Design and development of
geothermal cements typically centers on a minimum compressive stre