The In Situ Formation of Calcium Carbonate as a Diversion Agent for Use in Engineered Geothermal Systems


Pete Rose, Scott Fayer, Susan Petty, and Daniel Bour

Key Words:

diversion agents, EGS, hydraulic stimulation, calcium carbonate


Stanford Geothermal Workshop







File Size:


View File:


In the creation of Engineered Geothermal Systems, water is typically injected at pressures just below the least principal stress of the formation in order to open, through shear failure, partially sealed fractures that intersect the wellbore. Once a fracture (or set of fractures) is created, however, the stimulation fluid flows into the newly created fractures and is unavailable for subsequent fracture stimulation elsewhere along the wellbore. Fluid diversion agents are compounds that can serve to temporarily plug newly stimulated fractures and make the injected water available to stimulate new fractures. The diversion agent is subsequently removed to allow for flow from those previously sealed fractures. The in situ precipitation of calcium carbonate was studied for use as a diversion agent in Engineered Geothermal Systems. Urea thermally decomposes starting at about 150oC to ammonium and carbonate. In the presence of CaCl2 the carbonate subsequently precipitates to form CaCO3. This series of reactions was studied using a high temperature/pressure flow reactor over the range of 140-190C. Results indicate CaCO3 formation increases nonlinearly as a function of temperature.

ec2-18-204-56-97.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: ec2-18-204-56-97.compute-1.amazonaws.com (
Accessed: Thursday 29th of September 2022 05:03:24 AM