WorldWide Drilling Rescource

Tales from the Field by Jeremy C. Wire Geoconsultants, Inc. A Warm Well Almost Gets Us in Hot Water A client was planning a vineyard in our California Coast Ranges where previous experience dictated a drilling depth of no more than about 700 feet. However, groundwater levels were declining, and some- what deeper drilling only found relatively thick sections of clay, and the water in any of the accompanying thin sand units did not possess particularly good quality. In addition, the boron concentration was relatively high, not favorable for grapes. Our client was determined to develop a suitable groundwater supply, so why not drill a very deep well, say to 1800 feet and take a chance? Logs of some old gas and oil exploratory wells in the region suggested there might be a thick sand section below a depth of about 1200 feet, but overall water quality could not be determined with any certainty from available data. A location was selected, and test drilling revealed a sand about 900 feet deep and another thick section of sand from about 1200-1800 feet in depth. Some in-hole water sampling indicated the shallow interval contained excessive boron, but several tests in the deeper section found water of suitable quality. A large-diameter irrigation well was constructed to a depth of about 1800 feet and produced several thousand gallons per minute, and the water was very warm, about 120ºF (49ºC). Warm groundwater at depth is not rare in this region. The location was about eight mi les away from an area known for its thermal springs, and the observed temperature was anomalous, but not unusual considering the regional geothermal gradient. Several months later, we received a call from an engineer with the oil, gas, and geothermal division of the State Department of Conservation. He asked if we had been involved as a consultant in the project, which we acknowledged. He then stated the permit for the well should have been obtained from his department, and there could be negative consequences for whoever had been issued the permit, including the profes- sional drilling contractor. We noted the permit had been provided by the local county Environmental Health Department, and no quest ions were apparent l y raised that this location could result in a well which could be classified as strictly “geothermal”. After some further discus- sion, it was agreed we would send the agency all the logs and related construc- tion data for the well for their review. This must have provided evidence that this was not truly a “geothermal” well, as we never heard anything more from the agency regarding this possible classifi- cation. Since that time, we have driven past the vineyard several times, and the grapes seem to be thriving quite nicely on this very warm water. Jeremy Jeremy Wire may be contacted via e-mail to michele@ worldwidedrillingresource.com & rad Co v TGWA n T e Sh w en ion Annual t o groundwater and protect ex To develop, prom T Dallas Fri Embassy Sui January 2 . as ote, sco Hotel tes by Hilton 2-24, 2020 !NO ITACOL WEN Ed t Technol Trad Frisc Convention C f i Cl o ies, Poli y/R e Show, Latest g c o, TX enter & Spa W t W ll ule pda es, Industry U t Ou un o f w ive Scho Drill uca L f f ing hursd y i h ve yone a larship uc io ers and ump I on asses or P A t t e r t T a ni ht! t he opgolf n, and op he ns allers, a er e t t t t T g E-ma Phone: (512) 4 Contact In www.tgwa.org il: drobbins twca.org 72-7437 • Fax: (512) 4 formation: Dean Rob @ 72-0537 bins 37 WorldWide Drilling Resource ® OCTOBER 2019 GEO