Permian Takes A Public Hit

[Rodent + 1,424]

I'm not one for fear mongering, particularly for an industry like oil that already has a healthy dose of fear mongering spread daily. But the fact that the Permian, according to a new study, is sinking--literally--seems kinda scary. 

http://blog.smu.edu/research/2018/03/20/radar-images-show-large-swath-of-texas-oil-patch-is-heaving-and-sinking-at-alarming-rates/

Seems worthy of a bit of fear? Jaded research? Truth? A bit of both?

[carbonates + 22]

Its complicated, and while parts of this are true, some conclusions seem disingenuous to me as a geoscientist.  It is so complicated, it would be almost impossible to decide on a specific cause, or even a specific direction for the region. The Wink sinkholes they mention are localized phenomenon that are related to wells drilled in 1928 and abandoned in 1964. There are also some sinkholes related to salt removal wells that were deliberately removing salt by dissolution. Wink Sinks likely represents poor plugging procedures of the 1960's and do not represent the basin as a whole, but are isolated problems.  http://www.beg.utexas.edu/research/programs/near-surface-observatory/wink-sink  Much of the Permian is underlain by salt.  Removal of that salt by natural processes and the resulting subsidence has created natural wonders such as Carlsbad Caverns and Lechuguilla Cave by allowing acidic fluids related to oil to migrate upward into the Guadalupe range carbonates. In some areas natural gypsum karst is common at the surface and visible in deeper zones in seismic.  The Permian Basin's last gasp as an ocean basin filled it with water-soluble evaporites.  In some parts of the Permian the salt is deep enough to be ductile and movable (much like it is in the Paradox Basin of Utah). Deep magmatic fluids moving upward through faults can affect the salt significantly and part of the study's area includes a volcanic caldera that could be subsiding by cooling. The area is also bounded by the Rio Grande rift zone.

The Pecos River itself cuts across areas where it is very near or in contact with salt so the Pecos itself is carrying away salt. Water wells in this arid area are probably more likely to cause subsidence as they are frequently in unconsolidated Quaternary clastics that will lose porosity without hydraulic support.  Some ranchers even use brine wells to water livestock so they are pulling water from directly above the salt and removing it. Even the well-known Ogallala Aquifer lies over parts of the Permian and is slowly being drained by agricultural activities far north of the Permian. Isostasy related to the last Ice Age even plays a role, and many parts of the Gulf Coast and East Coast of the US are currently experiencing subsidence from this, so it stands to reason that the Permian could also be affected. Parts of the Permian are in the extensional domain of the Basin and Range province which has created subsidence such as below-sea-level Death Valley. I am aware of localized rising elevations caused by oil-field injection and flooding efforts, so while that part of their study is valid, I fail to get "scared" of this as the basin has clearly risen well over 1000 meters, and maybe 2000 m since the Laramide. We don't know how much Triassic, Jurassic, and Cretaceous sediment has been eroded away. Plate tectonics are what makes Earth a livable planet. Embrace it. Nothing is constant on this planet, especially not elevations. 

[Rodent + 1,424]

On 3/27/2018 at 12:37 PM, carbonates said:

Its complicated, and while parts of this are true, some conclusions seem disingenuous to me as a geoscientist.  It is so complicated, it would be almost impossible to decide on a specific cause, or even a specific direction for the region. The Wink sinkholes they mention are localized phenomenon that are related to wells drilled in 1928 and abandoned in 1964. There are also some sinkholes related to salt removal wells that were deliberately removing salt by dissolution. Wink Sinks likely represents poor plugging procedures of the 1960's and do not represent the basin as a whole, but are isolated problems.  http://www.beg.utexas.edu/research/programs/near-surface-observatory/wink-sink  Much of the Permian is underlain by salt.  Removal of that salt by natural processes and the resulting subsidence has created natural wonders such as Carlsbad Caverns and Lechuguilla Cave by allowing acidic fluids related to oil to migrate upward into the Guadalupe range carbonates. In some areas natural gypsum karst is common at the surface and visible in deeper zones in seismic.  The Permian Basin's last gasp as an ocean basin filled it with water-soluble evaporites.  In some parts of the Permian the salt is deep enough to be ductile and movable (much like it is in the Paradox Basin of Utah). Deep magmatic fluids moving upward through faults can affect the salt significantly and part of the study's area includes a volcanic caldera that could be subsiding by cooling. The area is also bounded by the Rio Grande rift zone.

The Pecos River itself cuts across areas where it is very near or in contact with salt so the Pecos itself is carrying away salt. Water wells in this arid area are probably more likely to cause subsidence as they are frequently in unconsolidated Quaternary clastics that will lose porosity without hydraulic support.  Some ranchers even use brine wells to water livestock so they are pulling water from directly above the salt and removing it. Even the well-known Ogallala Aquifer lies over parts of the Permian and is slowly being drained by agricultural activities far north of the Permian. Isostasy related to the last Ice Age even plays a role, and many parts of the Gulf Coast and East Coast of the US are currently experiencing subsidence from this, so it stands to reason that the Permian could also be affected. Parts of the Permian are in the extensional domain of the Basin and Range province which has created subsidence such as below-sea-level Death Valley. I am aware of localized rising elevations caused by oil-field injection and flooding efforts, so while that part of their study is valid, I fail to get "scared" of this as the basin has clearly risen well over 1000 meters, and maybe 2000 m since the Laramide. We don't know how much Triassic, Jurassic, and Cretaceous sediment has been eroded away. Plate tectonics are what makes Earth a livable planet. Embrace it. Nothing is constant on this planet, especially not elevations. 

Wow. Thanks for that detail. Always great to get a new perspective--especially an informed one.