Oil prices dipped back again to near 18-month lows on Friday, ahead of the New Year holiday.
Despite clawing back some of this week's losses hours earlier, brent crude at one point down by 56 cents to 51 dollars 60 a barrel before a slight recovery, as concerns resurfaced.
"At the moment, oil prices are declining both because of excessive supply, especially from U.S. shale oil production, plus weaker demand from China and other countries, especially in Europe. So it is a kind of perfect storm between too much supply and too little demand".
Volatility has been the hallmark of a year that's seen prices fall by 20 percent.
just this week, a 4.2 percent fall on Thursday followed one of the biggest daily gains in more than two years on Wednesday.
A bottom to the downside visible perhaps - but still relatively distant.
"Typically what happens once oil prices go towards 45 to 40 dollars per barrel, a lot of shale oil production will become unprofitable and what you will see is that in this case the oversupply especially from the U.S. will kind of disappear and dissipate slowly."
2019 will kick off with a supply cut to boost prices, OPEC and allies agreed this month to reduce output by more than 1 percent.
It comes into force in January.
"Cutting oil production might help to rebalance supply and demand in the oil market. However we have to be aware that a lot of OPEC countries in particular Iran are reliant on these oil exports in order to finance their government budgets".
Other analysts point to the global outlook.
And ask whether the slower growth many expect in 2019 will force oil producers to consider another, deeper cut in output, within months of the last one.