A Bloomberg article on who the winners and losers are when the price of oil gets cut in half [also keep in mind most natural gas is Brent-linked, meaning it's priced based on the value of oil] due to an oversupply in the market, which is estimated to be around 1.5 million bo/d - 2 million bo/d. Keep in mind that the growth in supply is slowing down as oil rigs are taken out of operation in North America and the "fracklog" [horizontal wells drilled but not completed and brought online yet] continues to grow. Check out the impact of low oil prices on various parts of the world here