User:Sdhamilton/sandbox

FIRST DRAFT OF ARTICLE

First draft of induced seismicity article:

Additions to lead section:

Induced seismicity can also be caused by the injection of carbon dioxide as the storage step of carbon capture and storage, which aims to sequester carbon dioxide captured from fossil fuel production or other sources in earth’s crust as a means of climate change mitigation. This effect has been observed in Oklahoma and Saskatchewan [3]. Though safe practices and existing technologies can be utilized to reduce the risk of induced seismicity due to injection of carbon dioxide, the risk is still significant if the storage is large in scale. The consequences of the induced seismicity could disrupt preexisting faults in the Earth’s crust as well as compromise the seal integrity of the storage locations. [6]

New section for induced seismicity:

While there is risk of induced seismicity associated with carbon capture and storage underground on a large scale, it is currently a much less serious risk than other injections. Wastewater injection, hydraulic fracturing, and secondary recovery after oil extraction have all contributed significantly more to induced seismic events in the last several years. [1] There have actually not been any major seismic events associated with carbon injection at this point, whereas there have been recorded seismic occurrences caused by the other injection methods. One such example is massively increased induced seismicity in Oklahoma, USA caused by injection of huge volumes of wastewater into the Arbuckle Group sedimentary rock. [2]

Mohr-Coulomb failure criterion

To assess induced seismicity risks associated with carbon capture and storage, one must understand the mechanisms behind rock failure. The Mohr-Coulomb failure criteria describe shear failure on a fault plane [4]. Most generally, failure will happen on existing faults due to several mechanisms: an increase in shear stress, a decrease in normal stress or a pore pressure increase [5]. The injection of supercritical CO2 will change the stresses in the reservoir as it expands, causing potential failure on nearby faults. Injection of fluids also increases the pore pressures in the reservoir, triggering slip on existing rock weakness planes. The latter is the most common cause of induced seismicity due to fluid injection. [5]

The Mohr-Coulomb failure criteria state that

critical=0 + (n -P)

with critical the critical shear stress leading to failure on a fault, 0 the cohesive strength along the fault, n the normal stress, the friction coefficient on the fault plane and P the pore pressure within the fault [3][2]. When  is attained, shear failure occurs and an earthquake can be felt. This process can be represented graphically on a Mohr’s circle [1] (link to other Wiki page)

Monitoring techniques

Since geological sequestration of carbon dioxide has the potential to induce seismicity, researchers have developed methods to monitor and model the risk of injection-induced seismicity, in order to better manage the risks associated with this phenomenon. Monitoring can be conducted with measurement from instruments like geophones (link to https://en.wikipedia.org/wiki/Geophone) to measure the movement of the ground. Generally a network of instruments around the site of injection is used, though many current carbon dioxide injection sites do not utilize any monitoring devices. Modeling is an important technique for assessing the potential for induced seismicity, and there are two primary types of models used: physical and numerical. Physical models use measurements from the early stages of a project to forecast how the project will behave once more carbon dioxide is injected, and numerical models use numerical methods to simulate the physics of what is occurring inside the reservoir. Both modeling and monitoring are useful tools to quantify, and thus better understand and mitigate the risks associated with injection-induced seismicity. [3]

Sources:

[1] NRC - National Research Council (2013). Induced Seismicity Potential in Energy

Technologies. Washington, DC: The National Academies Press. doi:10.17226/13355.

[2] "FAQs." Earthquakes in Oklahoma. N.p., n.d. Web. 27 Apr. 2017. <https://earthquakes.ok.gov/faqs/>.

[3] Verdon, J.P. and Stork, A.L. (2016), Carbon capture and storage, geomechanics and induced seismicity activity. Journal of Rock Mechanics and Geotechnical Engineering. Vol. 8, Pages 928-935. http://doi.org/10.1016/j.jrmge.2016.06.004

[4] Davis, S.D. and Frohlich, C. (1993), Did (or will) fluid injection cause earthquakes? - criteria for a rational assessment. Seismological Research Letters, Vol. 64, No.3- 4.,  https://scits.stanford.edu/sites/default/files/207.full_.pdf

[5] Riffault, J., Dempsey, D., Archer, R., Kelkar, S. and Karra, S. (2011), Understanding Poroelastic Stressing and Induced Seismicity with a Stochastic/Deterministic Model: an Application to an EGS Stimulation at Paralana, South Australia, 2011. 41st Workshop on Geothermal Reservoir

[6] Zoback, M. D., and S. M. Gorelick. "Earthquake triggering and large-scale geologic storage of carbon dioxide." Proceedings of the National Academy of Sciences 109.26 (2012): 10164-0168. Web.

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Topics:

1. Effects of global warming on marine mammals
2. Induced seismicity
3. Carbon neutral fuels
4. Membrane gas separations

Induced Seismicity

Induced seismicity

Talk:Induced seismicity#Proposed additions: UC Berkeley CCS class project contribution

Additions to lead section:

Induced seismicity can also be caused by the injection of carbon dioxide as the storage step of carbon capture and storage, which aims to sequester carbon dioxide captured from fossil fuel production or other sources in earth’s crust as a means of climate change mitigation. This effect has been observed in Oklahoma and Saskatchewan [9]

Though safe practices and existing technologies can be utilized to reduce the risk of induced seismicity due to injection of carbon dioxide, the risk is still significant if the storage is large in scale. The consequences of the induced seismicity could disrupt preexisting faults in the Earth’s crust as well as compromise the seal integrity of the storage locations. [10]

Sources:

[9]

http://www.sciencedirect.com/science/article/pii/S1674775516301196

“Injection of large volumes of carbon dioxide (CO2) for the purposes of greenhouse-gas emissions reduction has the potential to induce earthquakes. “

[10]

http://www.pnas.org/content/109/26/10164.short

“Earthquake triggering and large-scale geologic storage of carbon dioxide”

Other plans and other sources:

• Create a section for induced seismicity due to CCS
• Make a comparison of risks associated with natural gas storage/hydraulic fracturing/ wastewater injection and CO2 sequestration (use examples of Castor gas project in Spain or induced seismicity in Oklahoma due to wastewater injections)
• Describe the importance of understanding induced seismicity due to storing CO2 because the volumes of fluids injected in the case of CCS largely exceed volumes associated with waste water injection (see Figure 1 Verdon, J.P. (2014), Significance for secure CO2 storage of earthquakes induced by fluid injection, 2014, Environmental Research Letters, Vol. 9, doi:10.1088/1748-9326/9/6/064022.)
• Describe Mohr-Coulomb failure criteria and explain how underground injection can lead to an increase in normal stress, shear stress or pore fluid pressure changes leading to failure on an existing fault plane.

• Verdon, J.P. and Stork, A.L. (2016), Carbon capture and storage, geomechanics and induced seismicity activity. Journal of Rock Mechanics and Geotechnical Engineering. Vol. 8, Pages 928-935. http://doi.org/10.1016/j.jrmge.2016.06.004
• Davis, S.D. and Frohlich, C. (1993), Did (or will) fluid injection cause earthquakes? - criteria for a rational assessment. Seismological Research Letters, Vol. 64, No.3-4.,  https://scits.stanford.edu/sites/default/files/207.full_.pdf
• Riffault, J., Dempsey, D., Archer, R., Kelkar, S. and Karra, S. (2011), Understanding Poroelastic Stressing and Induced Seismicity with a Stochastic/Deterministic Model: an Application to an EGS Stimulation at Paralana, South Australia, 2011. 41st Workshop on Geothermal Reservoir Engineering, Stanford University. https://pangea.stanford.edu/ERE/db/GeoConf/papers/SGW/2016/Riffault.pdf

• Monitoring techniques

• seismic monitoring arrays (Verdon, J.P. and Stork, A.L. (2016), Carbon capture and storage, geomechanics and induced seismicity activity. Journal of Rock Mechanics and Geotechnical Engineering. Vol. 8, Pages 928-935. http://doi.org/10.1016/j.jrmge.2016.06.004)
• CO2 plume tracking in real time

• Look more closely at this source: http://ieaghg.org/docs/General_Docs/Reports/2013-09.pdf Induced Seismicity and its implications for CO2 storage risks, 2013, IEA Environmental Projects Ltd.\