NATURAL GAS EXPLOSIONS IN HUTCHINSON, KANSAS: LOCATING ABANDONED BRINE WELLS BY HIGH-RESOLUTION MAGNETIC AND ELECTROMAGNETIC SURVEY

A natural gas explosion on January 17, 2001 destroyed two downtown Hutchinson businesses. Another explosion occurred a day after at a mobile home park 3 miles away. Two residents died of injuries from the explosion, which forced the evacuation of hundreds of people as gas geysers began erupting in the area. The pathways to the land surface at both the explosion sites and the geysers were abandoned brine wells used for solution mining of salt.

To find these abandoned brine wells is a part of the Hutchinson Response Project. After successfully locating one uncapped abandoned brine well by an electromagnetic method during a testing phase in 2001, a high-resolution magnetic method was proposed to search for wells in 2002. The City of Hutchinson designed seven sites with a total area of 512,000 ft2 to search for abandoned brine wells after the City researched literature of the salt mining history in Hutchinson area. A high-resolution magnetic survey was conducted on these seven sites in May 2002. Twenty-three anomalies were verified by excavation with a backhoe, of which are five were identified as brine wells, four as suspected brine wells, one probable water well, and one probable gas pipe. A monopole anomaly with more than 12,000 nanoteslas in amplitude is a basic criterion to identify a well with an 8-inch metal case. A monopole anomaly with several thousand nanoteslas in amplitude is a basic criterion to identify a 2.5-inch or 4-inch well. The high-resolution magnetic method with theodolite-defined grids was successful in locating the abandoned brine wells in the City of Hutchinson, Kansas.