Terrel L. Shields
Elite Member
- Joined
- May 2, 2002
- Professional Status
- Certified General Appraiser
- State
- Arkansas
NAPA Valley reminds us that OK is experiencing a big uptick in earthquakes. Some claim it is all due to the oil business. While fracking itself does not appear to be a trigger in any case studies so far, the real culprit as a trigger may well be injection wells where waste water such as frack fluid flowbacks and salt water disposal has "greased the skids" so to speak.
Keep in mind that even where injection wells are clearly related to the movement, such as Guy, Arkansas, there is a geological reason. No where is there more injection wells that Texas and S. Arkansas yet there are virtually no quakes detected and none that are clearly related to injection let alone fracking.
35 years ago, there was a study done over 149 earthquakes that occurred in the previous 18 months. All were small compared to the Nov 2011 quake in OK and even the quakes back in the 1950s. But they all relate to the Nemaha Ridge that is a structural feature in the subsurface reaching from South Oklahoma all the way into Kansas where it then makes an eastward turn across that state and into south Nebraska.
The exact same area was affected by these quakes. These swarms simply appear then disappear for unknown reasons. Injection isn't the underlying cause so much as a sort of trigger that pushes the process along. At least that seems to be the consensus. In other words, similar swarms would have happened, at least on a smaller scale, over time even if no injection had happened.
It appears that high injection pressures (much higher that fracking pressures of Shale gas) may be creating internal rock pressures that sends fluids down the paths of least résistance, hence the fluid seeks out fault lines where the fractures associated with the fault may be receiving the bulk of the fluids under pressure and acting as a lubricant along these planes of weakness. Such faults may be under a lot of strain (physical pressure) and that injection fluid may just be the item needed to allow the fault to slip.
Again, the article from 35 years ago indicates that these quakes are not solely the result of injection, but are a geological feature that has likely been on-going for eons. And again it is over a broad area from El Reno on the SW to Perry in the NE and diagonally across the Nemaha Ridge which basically tracks I - 35 across the state.
PS.- I would certainly buy Quake insurance in Oklahoma and if in the area above I would want to add a disclaimer to the appraisal to the effect that we assume no liability for identification and assessment of damage the result of earthquakes.
http://www.ogs.ou.edu/pubsscanned/SPs/SP81_3.pdf
Keep in mind that even where injection wells are clearly related to the movement, such as Guy, Arkansas, there is a geological reason. No where is there more injection wells that Texas and S. Arkansas yet there are virtually no quakes detected and none that are clearly related to injection let alone fracking.
35 years ago, there was a study done over 149 earthquakes that occurred in the previous 18 months. All were small compared to the Nov 2011 quake in OK and even the quakes back in the 1950s. But they all relate to the Nemaha Ridge that is a structural feature in the subsurface reaching from South Oklahoma all the way into Kansas where it then makes an eastward turn across that state and into south Nebraska.
The exact same area was affected by these quakes. These swarms simply appear then disappear for unknown reasons. Injection isn't the underlying cause so much as a sort of trigger that pushes the process along. At least that seems to be the consensus. In other words, similar swarms would have happened, at least on a smaller scale, over time even if no injection had happened.
It appears that high injection pressures (much higher that fracking pressures of Shale gas) may be creating internal rock pressures that sends fluids down the paths of least résistance, hence the fluid seeks out fault lines where the fractures associated with the fault may be receiving the bulk of the fluids under pressure and acting as a lubricant along these planes of weakness. Such faults may be under a lot of strain (physical pressure) and that injection fluid may just be the item needed to allow the fault to slip.
Again, the article from 35 years ago indicates that these quakes are not solely the result of injection, but are a geological feature that has likely been on-going for eons. And again it is over a broad area from El Reno on the SW to Perry in the NE and diagonally across the Nemaha Ridge which basically tracks I - 35 across the state.
PS.- I would certainly buy Quake insurance in Oklahoma and if in the area above I would want to add a disclaimer to the appraisal to the effect that we assume no liability for identification and assessment of damage the result of earthquakes.
http://www.ogs.ou.edu/pubsscanned/SPs/SP81_3.pdf