Brussels intends to draft European Union-wide rules on tapping shale-gas reserves, Energy Commissioner Guenther Oettinger said on Friday, in the face of environmental concerns."I think we'll get a high level of acceptance when we have the same, European common standards, a high level of safety and security and quality for environmental interests," Oettinger told reporters during a visit to Wroclaw in southwest Poland."The best way is to Europeanise standard-efforts. We will bring some proposals to our member states maybe in the spring next year," he added.Speaking to a gathering of centre-right parties from across the 27-nation EU, Oettinger also said that he was seeking "environmental protection standards that enable member states to grant licences within a clear framework".Moves to tap gas from shale -- sedimentary rock containing hydrocarbons -- have sown deep divisions in Europe amid concerns that hydraulic fracturing used in its extraction is environmentally risky.France, for example, has frozen extraction projects and slapped a legal ban on so-called "fracking".But Poland is pushing ahead with moves to exploit reserves thought to contain some 5.3 trillion cubic metres of natural gas.If the estimate proves right, it would allow Poland reduce its reliance on coal for electricity production and it reduce its dependence on Russian gas supplies, which cover 40 percent of its needs.Little known even five years ago, tapping shale-gas is seen as having the potential to change global energy markets, for example by doubling the estimated reserves of the United States.