Study: Gas-charged fluids creating seismicity associated with a Louisiana sinkhole

Bayou Corne Sinkhole Expanding; Seismicity Increasing

Natural earthquakes and nuclear explosions produce seismic waves that register on seismic monitoring networks around the globe, allowing the scientific community to pinpoint the location of the events. In order to distinguish seismic waves produced by a variety of activities — from traffic to mining to explosions — scientists study the seismic waves generated by as many types of events as possible. In August 2012, the emergence of a very large sinkhole at the Napoleonville Salt Dome in Louisiana offered University of California, Berkeley scientists the opportunity to detect, locate and analyze a rich sequence of 62 seismic events that occurred one day prior to its discovery. . .  (more)

http://stateofthenation2012.com/?p=6139

Dutchsinse has more with graphics.

And The Examiner has more – Louisiana sinkhole ‘volcanic eruptions’, ‘explosions’ explained

Bayou Corne sinkhole collapses into AQUIFER

Bayou Corne Sinkhole Expanding; Seismicity Increasing

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4 thoughts on “Study: Gas-charged fluids creating seismicity associated with a Louisiana sinkhole

  1. Oklahoma related, but may be of interest: http://www.bbc.co.uk/news/science-environment-28128772

    Massive injections of wastewater from the oil and gas industry are likely to have triggered a sharp rise in earthquakes in the state of Oklahoma.

    Researchers say there has been a forty-fold increase in the rate of quakes in the US state between 2008-13.

    The scientists found that the disposal of water in four high-volume wells could be responsible for a swarm of tremors up to 35km away.

    Their research has been published in the journal, Science.

    Sudden swarm

    There has been increasing evidence of links between the process of oil and gas extraction and earthquakes in states like Arkansas, Texas, Ohio and Oklahoma in recent years.

    In 2011, a small number of people were injured and 14 houses were destroyed in the town of Prague, Oklahoma by a 5.7 tremor.

    Investigators linked it to the injection of wastewater from the oil industry.

    The US Geological Survey (USGS) has also reported on the question of seismicity induced by wastewater disposal.

    This new research goes further, linking a large swarm of Oklahoma tremors with a number of specific water wells, distantly located.

    More than 2,500 earthquakes greater than magnitude 3.0 have occurred around the small town of Jones since 2008. This represents about 20% of the total in the central and western US in this period.

    Researchers have now linked this increase to a near doubling in the volumes of wastewater disposed of in the central Oklahoma region between 2004 and 2008.

    Water is never far away in the energy extraction process. It is used not just for hydraulic fracturing, but also to squeeze more oil out of conventional wells.

    Large amounts of naturally occurring water are often released with the oil and gas – and this briny liquid needs to be separated from the fuels, using a method called “dewatering”.

    “There is a high ratio of water to oil,” said the study’s lead author Dr Katie Keranen from Cornell University.

    “It differs for each well. The typical nationwide ratio is five to one. We’re seeing much higher ratios, in the hundreds, at the beginning of the well.”

    According to Dr Bill Ellsworth from the USGS, the high price of oil has driven this water-based approach. But the law says that drinking water has to be protected from the salty flow.

    “As part of the business model, you have to be able to dispose of these very large volumes of saline water. You can’t treat it; you can’t put it into the rivers. So, you have to inject it underground.”
    Pressure points

    Four of the biggest of these wells in Oklahoma have been pumping around 4 million barrels of water a month to a depth of 3.5km beneath the surface.

    To determine the impact of this water, the scientists developed a model that could calculate the way the underground wave of pressure from these wells spread out.

    By comparing this to seismic data from the Jones cluster, it was concluded that the injection of wastewater is “likely responsible” for the swarm.

    “It is possible that pressure looks to have risen in the places where the earthquakes are occurring,” said Dr Keranen.

    “That pressure increase is what we see in natural triggering. So, if a fault is close to failure, the amount that the pressure is going up at these locations in our model is enough to push them over the edge.”

    The four wells that are the subject of the study are owned by a company called New Dominion. It insists that it operates its wells (named Sweetheart, Chambers, Flower Power and Deep Throat) safely and within permitted parameters.

    “The company notes the author did not consult with New Dominion’s geologist and engineers to determine whether her premises are in any way correct,” the company said in a statement.

    “At best, these incorrect assumptions are irresponsible.”
    Bigger triggers

    The authors say that they are uncertain about the potential for the large-scale disposal of wastewater to trigger events of larger magnitude.

    They point to an incident in 2010 when an earthquake ruptured a portion of a 7km long fault. If the entire fault had gone, the authors write, it could have led to a magnitude 6.0 tremor.

    “We often see more larger earthquakes when we see a lot of smaller ones,” said Dr Keranen.

    “But this is new situation with induced seismicity and we still have a lot of questions that we are trying to address.”

    This view is echoed by Dr Bill Ellsworth from USGS.

    “There are thousands of these wells in the US, so only a few appear to be problematic. The difficulties can be avoided but we need to know more about the process so we can give proper guidance to the authorities.”

  2. Looking at the fly over…June 11..shows the sunken berms..at the west and south sides. How soon before SLURP..and the water really swirls into the sinkhole??? Plus..gas..does that also suggest OIL?

    • I think it is untrue when they say they are no longer removing oily residue.
      Soon the new new south berm will look like west berm #1 … under water!

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