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:
ISSUES RELATED TO SEISMIC ACTIVITY INDUCED BY THE INJECTION
OF CO2 IN DEEP SALINE AQUIFERS
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

More Issues with Supercritical CO2

The quotes below come from the comments section on web site - http://tinyurl.com/owgbts

"First off, CO2 has what is known in the industry as a "triple point". A point on the temperature/pressure curve at which all three phases (liquid, solid, and gas) can co-exist. This is a dangerous situation because solids can plug up pipelines, liquids are incompressible, and gasses at that pressure are bombs waiting to blow. It is not at all uncommon for a pipeline to plug up due to a solid dry ice plug, burst due to the sudden spike in pressure from the incompressible liquids pumped in behind it, then flash to gas and cause an explosion. That is one reason it is not often used for oil well fracturing/stimulation, liquid nitrogen is far safer to handle/pump."

"The other issue is one of metallurgy. CO2, in the presence of water turns into carbolic acid. Carbon steel as well as most higher strength stainless steels are subject to severe pitting corrosion from carbolic acid. I have a piece of pipe that was in an oil well for two weeks in wet CO2 environment. It quite literally looks like a piece of wood that termites have been eating. Pitting corrosion is the most dangerous kind of corrosion because it is random and unpredictable in how deep it will go. Therefore you cannot build in a "corrosion allowance" into your designs to compensate for it the way you can with general corrosion. A corrosion allowance is when you specify a thicker wall for a pressure vessel than needed to account for the lost thickness due to corrosion over the vessel's life. But since pitting is localized and can go very deep very quickly, you cannot compensate for it in that manner."

"Carbolic acid also attacks the cement used to plug and case wells as well.

The way to compensate for it is to use group IV corrosion resistant materials. These materials are invariably very high Chrome, Nickel, Cobalt, and Molybdenum content materials. These are as you can imagine not cheap or plentiful, and were generally not used to drill or case the original oil wells that are to be used as CO2 injection wells. They also tend to present operational issues due to their propensity to gall. You cannot inject CO2 into a reservoir that has carbon steel cased wells that intersect it for there is a high likelihood that those capped wells may blow out later due to corrosion. Therefore using old oil wells is extremely problematic. Sure, it will work for a short time, but long term, those wells are ticking time bombs."

"Another issue is the energy required to capture, purify, liquefy, transport and pump the CO2. That energy has both a carbon and a financial cost associated with it. What good does it serve to sequester 1 MMCF of CO2 if you generate 1.25 MMCF in the process?

For example, carbonic acid in groundwater can dissolve limestone to form natural caves. We don't know what type of effect pumping such a volume of CO2 into the ground would have, so saying there could be an off-the-shelf system in the near-term is not reasonable."

Below are excerpts from the web site -

http://tinyurl.com/ov9264

"Potential problems

Beside the problem of carbon dioxide leaking out of old abandoned wells, there are other concerns.

Forcing carbon dioxide under pressure into rock formations could force natural gas and salt water out of those formations in unpredictable and undesirable ways – into shallow water wells, for example or to the surface, spilling natural gas (a potent greenhouse gas) into the atmosphere, or pushing brine into fresh water aquifers.

And in an ironic reversal, pumping gas under pressure into some rock formations could cause the surface of the ground to actually rise – as opposed to land subsidence caused by deep mining coal – damaging structures and affecting streams and drinking water aquifers.

Leaking carbon dioxide could find its way into drinking water aquifers, and while this sounds like it could produce club soda from the kitchen faucet, it would make the water more acidic, dissolving calcium and other minerals and creating a hard water problem, or in some cases dissolving toxic metals, raising trace elements to dangerous levels."

WARNING - CO2 Sequestration Danger - What goes into the ground is NOT bubbles or carbonation!

It is supercritical CO2 and carries a lot of risks -

The full article is here - some excerpts from the article are below

Health hazards from CO2

"At room temperature and ambient pressure, CO2 is a colourless, odourless gas that supports neither combustion nor life. It is not just an asphyxiant but also has toxicological effects and has been recognised as an occupational health hazard for more than a hundred years.

Dense phase and supercritical CO2 give rise to additional hazards particularly when the pressure suddenly falls or is lost completely."

Further information on the cryogenic, traumatic and toxicological effects



General hazards of carbon dioxide

At room temperature and ambient pressure CO2 is a colourless, odourless gas that will not support combustion or human life. CO2 has been recognised as a workplace hazard for over a century. It is significantly heavier than air and many fatalities from asphyxiation have resulted from entry into pits, tanks, sumps or cellars where CO2 has accumulated and displaced oxygen.

It is also possible for dangerous levels of CO2 to form out-of-doors in trenches, depressions or valleys. This is particularly likely when the gas is colder than the surrounding air, which may occur following pressurised release.

In 2000, a US Environmental Projection Agency study on CO2 related incidents in fire scenarios reported that since 1975 there were 51 recorded incidents involving the discharge of CO2 fire extinguishing systems resulting in 72 deaths and 145 injuries.

There is no significant inherent human response to CO2 that could be useful as a detection mechanism. Human response to hydrogen sulphide by smell occurs at very low (ppm) concentrations, similarly with ammonia and sulphur dioxide.

In contrast, CO2 is present in the air we breath (0.037%). This may cause problems with instrumented detection because the 'background' CO2 levels are so high. In addition, the cooling effects of a pressurised CO2 leak may have an adverse effect on the accuracy and operability of CO2 gas detection systems.

The recognition of the dangers of CO2 has prompted much research into its toxicity in both human volunteers and animals. It is now known that, in addition to the problem of asphyxiation due to the displacement of oxygen, the inhalation of elevated concentrations of CO2 can increase the acidity of the blood triggering adverse effects on the respiratory, cardiovascular and central nervous systems. Data from published research reports has been used by HSE to quantify the toxicity of CO2 in the form of Dangerous Toxic Load (DTL)1 values.

The DTLs have been used in calculations by the Health and Safety Laboratories (HSL) to demonstrate that CO2 exhibits major accident potential, when transported by pipeline in large quantities at ambient temperature and at a pressure of 7 bar or more, well below the dense phase or supercritical region. It is not yet clear whether controls should be applied to the transport of CO2 in this context but pending further research, it is possible that HSE will propose amending the Pipelines Safety Regulations to include CO2 as a dangerous fluid.

Additional hazards of dense phase or supercritical carbon dioxide

For economic and technical reasons it is likely CO2 will be handled close to or above its critical pressure (73.82 bar) where many of its properties are similar to that of a liquid. In this state it is often referred to as a dense phase fluid, whereas above critical temperature (31.04oC) and pressure it is referred to as supercritical. Most of the additional hazards associated with dense phase or supercritical CO2 arise when this pressure suddenly falls or is lost completely.

Scale of the thermal cooling envelope

In the event of a major pressure loss, e.g a pipe rupture or containment failure, the depressurisation will result in an increase in the volume occupied by the CO2 of several hundred fold as the escaping fluid undergoes a rapid expansion (and phase change) as a proportion essentially 'boils' and becomes a gas while the remainder forms solid particles. This rapid, violent expansion causes the temperature of escaping CO2 to fall very rapidly, frequently below -80°C. while the particles of solid CO2 formed (dry ice) will result in projectiles expelled at very high velocities.

Cryogenic burns and impact injuries from extremely cold jet of gas and entrained missiles are serious hazards to personnel. Cryogenic embrittlement of structural steelwork and adverse effects from the impingement of extremely cold gas jets on safety-critical equipment are major threats to the structural and functional integrity of nearby plant unless appropriately designed or protected.


Toxic contamination effects

Supercritical CO2 is a highly efficient solvent. When supercritical CO2 undergoes a significant pressure reduction it moves from its supercritical state with super solvent properties to a gaseous state with virtually no solvent capability. In any environment where other substances are present with supercritical CO2 their solvation will occur resulting in fluid medium or "solution" containing various compounds or elements many of which may be extremely toxic. Any toxic substance held in such a pressurised 'solution' will 'precipitate' out on loss of pressure or containment and is likely to result in harmful human exposure or environmental damage due to the contamination of the area of deposition unless appropriate measures are taken.


Dry Ice 'grit blasting effects'

Where captured CO2 may be present with solid particles such as reservoir-derived sand and other solid debris, loss of containment may result in these combining with the dry ice formed to produce particles of a much greater abrasive capability than dry ice alone. This would enhance the erosion effects on process pipework and vessels adjacent to the leak which could lead to further damage to equipment and hence risk to people.


Specific challenges associated with dense phase or supercritical carbon dioxide

Whilst the processes that make up Carbon Capture and Storage (CCS) are not novel in themselves there is relatively little experience worldwide in managing the risks associated with CO2, compared with oil and gas. The major accident hazards presented by handling high pressure CO2 offshore or onshore need to be considered in the context of about 10,000 years' operating experience in managing hazards associated with hydrocarbon processing offshore alone, and probably much more if onshore processes are included2. In comparison there are probably less than 100 operating years for handling CO2 and significantly less in dealing with supercritical CO2. For Example, the Sliepner CO2 disposal project has been operational since about 1996 while in the USA, CO2 injection into wells has only been carried out over the last ~40 years.


Modelling dense phase/supercritical CO2 releases

The ability to anticipate foreseeable major accident scenarios and accurately predict the consequences of these hazardous events is a fundamental element in the assessment of the risk. A lack of substantial operation experience in a novel process or technology generally leads to significant difficulties in identifying accurately the hazards associated with that process or technology.

We do not yet fully understand the behaviour of CO2 when released from dense phase. Industry is researching appropriate models which will need to be validated. There is a need for appropriate scale experimental work to provide HSE and duty holders with a thorough understanding of how CO2 behaves during foreseeable large releases.

Containment and integrity

Whilst there are applicable general engineering standards, there is a lack of internationally recognised standards and codes of practice specifically for dense phase or supercritical CO2 plant and equipment. When designing, fabricating and maintaining plant for handling and transporting CO2 it is important that the full significance its physical properties, at the temperatures, pressures and inventories required are fully recognised and managed accordingly. Where applying standards developed for other substances including hydrocarbons, such as natural gas, extreme caution is advised as even the highest standards for many other substances may not be sufficient to ensure adequate containment for CO2 under the expected, and unexpected operating envelope(s).

Aspects of induced seismic activity and deep-well sequestration of carbon dioxide

"Aspects of induced seismic activity and deep-well sequestration of carbon dioxide"

From the GeoScience World web site - click here to access it

Supercritical Fluid Processing for Renewable Energy

If they really wanted to capture the CO2 and eliminate it they would be doing something that is "green", like turning the captured and condensed CO2 - which is called Supercritical CO2 or Supercritical Fluid into Renewable Fuel or sell it to industry where it is used as a solvent.

Check out this presentation to see more about this and to realize how acidic this form of CO2 is... it even dissolves glass! This is the same stuff they want to put into the ground FOREVER.