The cold spell that swept across the United States this weekend has caused a drop in oil production of up to 2 million barrels daily, Reuters reported, citing analysts and traders. According to estimates by Energy Aspects, the Permian alone saw production outages of around 1.5 million barrels daily. However, production is already recovering, and the lost output in the Permian is down to some 700,000 barrels daily. Output is expected to be fully restored by the end of the month. Bloomberg reported Monday that refiners were also curtailing operations…