Oklahoma Earthquake and Fracking

[garybeck]

Oklahoma Earthquake & Fracking

BY ZACHARY SHAHAN



...As reported last week, even a fracking company in England has now stated that fracking is the “probable” cause of recent earthquakes there. In September, we reported that the Arkansas Oil and Gas Commission has banned fracking disposal wells for unconventional gas drilling wastes due to earthquakes....

... in 2010, after fracking started in the state (AR), the number of earthquakes was over 600 — about as many as in Arkansas in the last 100 years! Connection?...

...In Oklahoma, the situation is quite similar. The largest earthquake that hit Oklahoma this weekend, a 5.6-magnitude tremor near Sparks, was the largest on record in the state. Dozens of earthquakes hit Oklahoma on the weekend. Oklahoma has seen the same rise in earthquake activity that Arkansas saw. Going from about 50 earthquakes a year up until 2009, the state got 1,047 last year!...

...OK, now, how can fracking be related to earthquakes? It’s actually the disposal wells that seem to cause the problem. Fracking involves high-pressure injection or pumping of fluids into the ground,.. in order to open up cracks in the rock for natural gas to escape and be capture.
Hmm, open up cracks in the rock... While it seems fracking doesn’t cause earthquakes immediately, it lowers the barriers to earthquakes happening, loosens up the rocks enough that it is more likely to happen. In Arkansas, they noticed that it was especially the wastewater disposal wells that seemed to be setting the stage for earthquakes. As quoted above, when these wastewater disposal wells were shut down — high-pressure injection of wastewater was stopped — the number of earthquakes diminshed back down to a more normal level soon after....

Full Article:
http://planetsave.com/2011/11/07/oklahoma-earthquake-fracking/

[garybeck]

1. Wow I'm amazed someone would UNrec this. Just went from +1 to 0, it would be interesting

if records recs and unrecs were made public.

[cui bono]

2. Stop fracking around FFS!!! n/t

[Beartracks]

3. I saw this report on fracking on a Twitter link...

... the other day. Published by the OK Geological Survey, it describes seismic activity in Garvin County in central Oklahoma, maybe about 80 miles SSW of Lincoln County where the weekend quakes occurred.

Examination of Possibly Induced Seismicity from Hydraulic Fracturing in the Eola Field, Garvin County, Oklahoma - Summary

"On January 18, 2011, the Oklahoma Geological Survey (OGS) received a phone call from a resident living south of Elmore City, in Garvin County, Oklahoma, that reported feeling several earthquakes throughout the night. The reporting local resident had also offered that there was an active hydraulic fracturing project occurring nearby. Upon examination there were nearly 50 earthquakes, which occurred during that time. After analyzing the data there were 43 earthquakes large enough to be located, which from the character of the seismic recordings indicate that they are both shallow and unique. The earthquakes range in magnitude from 1.0 to 2.8 Md and the majority of earthquakes occurred within about 24 hours of the first earthquake. Careful attention and significant effort was put into obtaining the most accurate locations possible and gaining a reasonable estimate in the error in locations. The nearest seismic station is 35 km away from where the earthquakes occurred. Formal errors in location are on the order 100-­‐500 m horizontally and about twice that for depth. Examination of different velocity models would suggest that the uncertainties in earthquake locations should be about twice the formal uncertainties. The majority of earthquakes appear to have occurred within about 3.5 km of the well located in the Eola Field of southern Garvin County. The Eola Field has many structures, which may provide conduits for fluid flow at depth. The well is Picket Unit B well 4-­‐18, and about seven hours after the first and deepest hydraulic fracturing stage started the earthquakes began occurring. It was possible to model 95% of the earthquakes in this sequence using a simple pore pressure diffusion model with a permeability of about 250 mD (milliDarcies). While this permeability may be high it is less than those reported for highly fractured rock. The strong correlation in time and space as well as a reasonable fit to a physical model suggest that there is a possibility these earthquakes were induced by hydraulic-­‐fracturing. However, the uncertainties in the data make it impossible to say with a high degree of certainty whether or not these earthquakes were triggered by natural means or by the nearby hydraulic-­‐fracturing operation. "

Full report: http://www.ogs.ou.edu/pubsscanned/openfile/OF1_2011.pdf


This sentence in the summary stood out to me: "About seven hours after the first and deepest hydraulic fracturing stage started the earthquakes began occurring."

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[garybeck]

4. if I could REC your comment I would. n/t