County supervisors have outlawed drilling of certain new oil wells in the vicinity of a major aquifer for 45 days in light of water-safety questions. The decision Tuesday by the Ventura County Board of Supervisors came a couple of months after scientists at the U.S. Geological Survey reported that they had found petroleum-related gases in wells supplying irrigation water on the Oxnard Plain.The moratorium applies to the drilling of new wells and the re-drilling of existing ones near the Fox Canyon Aquifer, which is described as a major source of drinking quality groundwater.