(Sharecast News) - Jersey Oil&Gas shares' crashed after notifying that an appraisal well had failed to find Upper Jurassic sands, leading it to lower its estimate for the prospectivity of the discovery, although it was still deemed "commercially viable".The 20/05b-14 appraisal well was drilled ahead of schedule and on budget to a depth of 3,784m, but based on preliminary observations, Jersey said the Verbier discovery's contingent resource volumetric estimations were likely to be marked down to the lower end of its initial resource estimate of 25m barrels of oil equivalent announced two years ago.However, "a large part" of the mapped area of Verbier located to the north west of 20/05b-14 remained untested and additional resource potential had been found in a deeper horizon below the same discovery.Andrew Benitz, Jersey Oil & Gas chief, commented: "We are both surprised and disappointed by the results of our appraisal well. JOG remains confident that Verbier is a commercially viable development project that could be further enhanced by the potential for a new area hub development, together with undeveloped discoveries that sit in close proximity to Verbier."Verbier has been a play-opener for JOG and we remain excited about the growth potential surrounding this valuable asset. JOG remains well-funded to pursue our growth plans and will continue to assess various acquisition opportunities as we move forward."The company held an 18% share of the P2170 license, alongside Equinor UK with 70% and CIECO V&C at 12%.