Royal Dutch Shell may invest no less than $1 billion in geological exploration and production of shale gas in the Kharkiv region in north-east Ukraine, Deputy Governor Yury Sapronov said on the regional government website on Wednesday. \"Preliminary data say the company has examined the Izyumsky district as an area for gas production. Project development may take three to five years,\" Sapronov said in a statement. Ukraine, unhappy with its dependence on from Russian gas, is seeking alternative energy sources. The government has started actively discussing the production of shale gas, with deposits possibly located in the Donetsk Basin in eastern Ukraine and the Carpathian region in the west. The U.S. Geological Survey estimated shale gas reserves in Ukraine at 1.5-2.5 trillion cubic meters, but those figures may increase, Ukraine\'s energy company Naftogaz said.