NATURAL GAS EXPLOSIONS IN HUTCHINSON, KANSAS: RESPONSE TO A GEOLOGIC MYSTERY

Natural gas eruptions and geysers burned businesses and killed two people in Hutchinson, a town of 40,000 in central Kansas, in January 2001. Gas reached the surface through unplugged brine wells drilled as long ago as the early 1900s. The gas eruptions coincided with a leak of 143 MMCF of natural gas through a shallow hole in the casing of a wellbore into a solution cavern in the Permian Hutchinson Salt at the Yaggy gas storage field 7 miles northwest of the town.

In order to return hundreds of evacuees to their homes and the city to normalcy, a dozen scientists of the Kansas Geological Survey undertook a wide-ranging geological and geophysical exploration program to identify gas pathways and accumulations under the city for venting.

Only about 20% of the initial relief wells drilled to vent the gas from under the city encountered any gas. No simple geologic model allowed easy prediction of pathways to locate additional vent wells. Seismic reflection lines indicated two amplitude anomalies that were drilled and found to produce gas. Well logs and cores from newly drilled vent wells in Hutchinson were correlated with similar data and archived samples from oil, gas, and water wells in the region. Questions remain about the nature of the geologic path for the gas, compartmentalization of the leaked gas, near-wellbore formation damage, the amount of gas remaining under the city, and whether the gas storage field can be re-opened. An experimental search for buried brine wells is successfully under way using electromagnetic methods. Monitoring of water wells for potential gas contamination and saltwater intrusion was inconclusive. The Survey website at (http://www.kgs.ukans.edu/Hydro/Hutch/index.html) served as a near real time progress report throughout the response effort and as a source of related materials.