Natural Gas Stocks Injection in Bulgaria increased to 28.66 GWh/d on Thursday September 4 from 28.60 in the previous day. Natural Gas Stocks Injection in Bulgaria averaged 9.91 GWh/d from 2011 until 2025, reaching an all time high of 48.40 GWh/d in May of 2012 and a record low of 0.00 GWh/d in January of 2011.