Saturday, June 13, 2009

Injection Induced Earthquakes AND Special Considerations Supercritical Liquid Properties

When most people think about Carbon Capture and Storage they think it means putting bubbles in the ground or carbonation, like we find in soda pop. The reality is not even close to anything resembling bubbles and it is dangerous.

Before the CO2 they capture can be put into the ground it must be transformed into SUPERCRITICAL CO2 which is considered a Supercritical Liquid - which is a supersolvent and comes with a lot of risks.

The article below comes from:
Joel Sminchak and Neeraj Gupta

I could not find a date on this abstract. Some random quotes from it are listed below.

Please read the entire article - I have just excerpts here.

The live link to this article is here
(bold areas in the quoted material below have been done by me to help those who skim over articles)

Consequently, the injected CO2 must be addressed as a multiphase system. Special considerations for underground disposal of CO2 are mostly related to the unique properties of supercritical CO2.

"Formation Dissolution/Weakening
Supercritical CO2 has the potential to dissolve, weaken, or transform the minerals in the injection formation. In the supercritical state, CO2 becomes a “supersolvent.” Thus, there is potential for the fluid to dissolve and weaken the rocks in the injection formation. If the rock formation is weakened, the potential for hydraulic fracturing increases. Dissolution of minerals precipitated along a fault will reduce the strength of the fault, possibly moving the fault to frictional sliding conditions where failure is more likely to occur."

Case Study: Seismic Aspects of Deep Well Injection in Ohio
Deep well injection practices and seismic activity in Ohio were examined to determine the potential for induced seismicity in the state. All five active deep well injection systems in Ohio have been investigated for seismic hazards to some extent.
Most faults in Ohio are associated with Precambrian basement rocks at depths over 1 km below land surface. Several faults have been identified in northwestern Ohio, while relatively few faults have been identified in the rest of the state. The Anna Seismogenic Region is one of the most active seismic zones in Ohio (Figure 4). The zone is located in west-central Ohio. (Note by me - Greenville, OH is considered to be part of the Anna fault)

"In general, most seismic activity indicates strike-slip movement along steeply dipping faults. Based on the USGS Seismic Hazard mapping project, there is a low probability for damage from earthquakes for Ohio, except in the Anna Seismic Area, which has a moderate hazard.

The Anna Seismic Seismogenic Region in west-central Ohio has been identified as one of the most active seismic areas in the Midwest. The area has a substantial history of seismic activity dating back to the mid-1800s. The largest earthquake observed in the area had a Modified Mercalli intensity of VIII in 1937. In general, seismic activity indicates northeast-southwest strike-slip movement oriented perpendicular to the predominant stresses in the area."

"A number of faults have been proposed in the area, but most activity appears to occur near the trend of the proposed Anna-Champaign Fault. Overall, the Anna Seismic Area is considered a seismically active area."

Acknowledgement: The work presented here was conducted with funding from the U.S. Department of Energy’s National Energy Technology Laboratory as part of project number DEAF26-99FT0486."

To read the entire abstract click here