Oil prices refused to move in tandem on Tuesday, as the two main futures contracts Brent Crude and Nymex West Texas Intermediate moved in different directions.
Brent, the global benchmark, has seen its premium pricing over WTI - known as the spread - wither in recent weeks.
US crude stockpiles have continued to build in recent weeks, but exports have grown - leaving something of a hole at the chief US oil hub at Cushing, Oklahoma.
"This has left stocks in the hub below the five-year average for this time of year," said Warren Patterson at ING.
"The drawdown in inventory has been supportive for WTI, with the Brent-WTI spread narrowing from almost US$7 per barrel at the end of December to around US$3.20 a barrel currently."
Meanwhile, the restoration of full capacity from the Forties pipeline in the North Sea - closed for several weeks for repairs after a crack was discovered in December - has eased concerns over the supply of Brent crude.
Data from the Commodity Futures Trading Commission for last week showed that speculative long positions for Brent futures - those backing price gains - were further reduced.
However, since the data was compiled, Brent crude has risen nearly 5%, and Tuesday's drop looked more technical rather than based on supply and demand fundamentals.
Indeed, Patterson at ING suggested: "Given the price action since the last reporting week, the next report is unlikely to show further liquidation in speculative longs."
Brent crude prices also displayed what is the usual reaction to currency effects. A stronger dollar on Tuesday saw most commodity prices – which are denominated in the US currency – fall.
WTI’s positive reaction appeared, therefore, to be largely supported by demand and supply fundamentals in its domestic market.
While oil prices have traditionally moved in tandem on risks to global supply and demand, the domestic factors currently in play in the oil markets kept price movements apart on Tuesday.
By mid morning in London, Brent was down 0.72% at $65.22 a barrel, while Nymex WTI gained 0.81% to $62.05.