Hutchinson natural gas explosion
In January 2001, natural gas explosions in the central Kansas town of Hutchinson killed two people, destroyed two downtown businesses, and created a series of geyser-like spouts of water and gas. The Kansas Geological Survey was instrumental in determining the source of the gas and remediating the problem. KGS researchers used shallow seismic reflection techniques to identify the pathway of the leaking gas and examined geologic data collected over decades to identify where the natural gas was coming from and where it still presented a danger.
The source of the gas was determined to be a natural gas storage facility west of Hutchinson. In the 1980s, underground caverns had been created to store propane in a layer of salt called the Hutchinson Salt Member of the Wellington Formation, about 500 to 600 feet below ground. The impermeable rock above the salt layer prevented the gas from flowing up to the surface. However, when a hole developed in a pipe used to move gas in and out of the underground caverns, the highly pressurized gas escaped through the hole and worked up to a permeable layer. The gas then migrated miles underground until it found outlets—long forgotten abandoned brine wells used to mine salt—to the surface.
KGS geophysicists located the metal casing of several abandoned brine wells using electromagnetic methods so that they could be plugged. To release the escaped gas still under the city, the company that owned the natural gas storage facility drilled vent wells to release any remaining gas under the city. After the gas flow from the vent wells subsided, the KGS coordinated two NASA flights over Hutchinson and Reno County to make sure no gas leaks had gone undetected.
The Hutchinson Gas Explosions: Unraveling a Geologic Mystery (pdf) by M. Lee Allison, Kansas Geological Survey (Kansas Bar Association, 26th annual KBA/KIOGA Oil and Gas Law Conference, 2001)