Shares in Tullow Oil took a tumble on Monday afternoon after the group announced that it has plugged and abandoned a well in Guyana due to safety concerns.The Jaguar-1 well in the Georgetown Block, offshore Guyana in which it has a 30% interest, drilled to a depth of 4,876 metres without reaching the primary Late Cretaceous objective."The decision to stop drilling at this point was unanimously agreed by all partners based on safety criteria and was taken after reaching a point in the well where the pressure design limits for safe operations prevented further drilling to the main objective," the company said.The high-pressure, high-temperature well was spudded in February. Tullow said that samples of light oil were successfully recovered from two Late Cretaceous turbidite sands above the primary objective.By 14:50, shares were trading 3.35% lower at 1,385p.BC