WTI for January delivery settled down $1.90, or 3.3%, to $55.91 a barrel on the New York Mercantile Exchange, the lowest level since May 5, 2009.
Brent, the global benchmark, fell 79 cents, or 1.3%, to $61.06 a barrel on ICE Futures Europe, the lowest settlement since July 2009.
Oil prices have been sliding for months and continue to decline near the year's end as OPEC pledged to maintain production despite a global oversupply. The organization has said cutting output would have little effect on price and would only lead to a surrender of some market share, according to CNBC.
Additionally, on Friday, the Denver-based oil company lowered its production guidance for the fourth quarter and 2015, and its 2015 capital expenditure guidance amidst falling oil prices.
Separately, TheStreet Ratings team rates EMERALD OIL INC as a Sell with a ratings score of D. TheStreet Ratings Team has this to say about their recommendation:
"We rate EMERALD OIL INC (EOX) a SELL. This is driven by multiple weaknesses, which we believe should have a greater impact than any strengths, and could make it more difficult for investors to achieve positive results compared to most of the stocks we cover. Among the areas we feel are negative, one of the most important has been a generally disappointing historical performance in the stock itself."