Brine Well Background
The Carlsbad Brine Well cavity was created by dissolving and extracting the subsurface salt deposit in the form of brine (salt-laden water). The well operated from 1978 until July of 2008, when activities were ceased because of the concern of a potential collapse. The brine making operation consisted of two wells named Eugenie #1 and Eugenie #2. A fracking procedure at Eugenie #2 was conducted in late 1979 to increase brine production.
On July 16, 2008, a brine well southeast of Artesia, NM catastrophically collapsed leaving a surface sinkhole several hundred feet across and more than 100 feet deep. Within days New Mexico Oil Conservation Division (OCD) personnel became concerned about the brine operation in Carlsbad which was similar in operation to the one that collapsed. On July 22, 2008 brine production from the Carlsbad Brine Well was terminated at OCD’s direction and the well was later plugged. The EMNRD Cabinet Secretary directed the division to evaluate all rules regarding brine wells, audit available records, inspect all active brine wells, continue monitoring the first collapse, and work with other agencies to assess situation.
On November 3, 2008 a second brine well collapse occurred north of Loco Hills, NM and a moratorium on new brine well permits was put into effect. On March 11, 2009 OCD recommended to the operator of the Carlsbad well that they consider shutting down surface operations above their cavern and submit contingency planning for a possible collapse including discussions with their neighbors. On March 26th and 27th of 2009, a gathering of regulators, technical experts, and industry was held to discuss overall brine well safety during which a consensus developed that the brine cavern in Carlsbad had a high probability for collapse.
Since April of 2009, the division has briefed emergency response organizations, local government, the state Departments of Transportation and the Environment, along with the public about the situation on numerous occasions. OCD also contracted with a capable engineering firm to undertake characterization of the brine cavity and install an automated system to detect ground movement. This early warning system became operational on June 23, 2009.
Numerous geophysical and remote sensing studies were conducted to evaluate the nature and extent of the cavern. Additional and upgraded equipment to monitor ground movement was installed in 2014, 2017, and 2019. Drilling was conducted in the area surrounding the cavity to further help understand the site-specific geology. Based on the information collected, several conclusions about the cavity were made:
- The main cavity is approximately 350 ft. wide by 700 ft. long with a maximum height of about 150 ft
- The top of the cavity is approximately 450 below the surface
- The cavity is not entirely an open void, but is made up of a mix of solids and brine
- One or more open voids may be present within the cavity
Investigations prior to 2019 provided data, information, and insights into the nature of the cavity; however, they have been subject to limitation. To avoid accidental depressurization and potential for induced collapse, past investigations have specifically avoided penetrating the cavity. Therefore, the exact nature of materials filling the cavity are being discovered as part of the Remediation Project.