Strength Retrogression in Cements under High Temperature Conditions


Ben Iverson, Joe Maxson, Daniel Bour

Key Words:

Cement Strength Retrogression Silica


Stanford Geothermal Workshop




Field Studies



File Size:


View File:


Cement designs for high-temperature geothermal applications have typically included 35 to 40% additional crystalline silica to help prevent loss of compressive strength and an increase in permeability. This was based on research performed on Portland-cement systems, which indicated that at temperatures above 230F, additional silica was required to provide a high-strength stable crystalline structure. This standard has been used by the industry for many years, both in geothermal-well applications and high-temperature oil- and gas-well applications. New research, however, has shown that 40% additional silica can be inadequate to provide a high-strength, low-permeability cement at temperatures typical for geothermal-well conditions of around 500F or higher. This research also indicates that larger amounts of silica might be required to provide long-term strength stability in cements that are typically used in geothermal-well applications.

Preliminary results of this research are provided, including strength- and permeability-test results on cements cured at temperatures from 500 to 650F, as well as a discussion on the associated crystalline phases found in these samples. In addition, a discussion of the practical ramifications, ongoing research, and additional research needed in this area is included.

ec2-44-200-101-84.compute-1.amazonaws.com, you have accessed 0 records today.

Press the Back button in your browser, or search again.

Copyright 2010, Stanford Geothermal Program: Readers who download papers from this site should honor the copyright of the original authors and may not copy or distribute the work further without the permission of the original publisher.

Attend the nwxt Stanford Geothermal Workshop, click here for details.

Accessed by: ec2-44-200-101-84.compute-1.amazonaws.com (
Accessed: Monday 02nd of October 2023 07:01:05 AM