If there's one oil chart you need to see, it's this one

Tensions on the Ukraine-Russia border may have rallied crude oil on Friday but the commodity is still down by 10 percent over the past two months.

According to one highly regarded technical analyst, oil prices may continue moving down. Louise Yamada, managing director of Louise Yamada Technical Research Advisors, sees the potential for lower oil prices.

"Earlier in the year, we were talking about a sideways consolidation," said Yamada. After a huge run-up to more than $146 per barrel in 2008, oil prices saw "a reversion to the mean, so to speak, after such an incredible lift. It has essentially been in a trading range of roughly between $80 and $115" since 2011.

(Read: Oil soars as Ukraine strafes Russian convoy, renews risk premium)

Yamada believes that a trend began emerging within that wide range a couple of years ago. "In 2012-2013, we started to see a series of higher lows come into place, which established an uptrend," she said.

But that changed after oil prices began falling in June. "It's conceivable it could slip a little bit further," Yamada said. "The uptrend is broken and you've obliterated the series of higher lows by breaking below the early 2014 lows."

Even if overseas tensions cause oil prices to move higher, it will have to get over resistance at $100, $103 and $105, said Yamada. "Otherwise I think it could continue to slip," she added. "It's been astounding that you haven't had a soaring oil price given all the [previous] geopolitical issues."

(Read: Ukraine hits at Russians: Here's what may be next)

Should oil prices slide under the $90 level, Yamada sees two big support levels below. "You could see $85 which is your next support [going] back to 2012," she said.

Beyond that, Yamada thinks prices could hit somewhere between $78 and $80, the bottom of the trading range that began around 2011. "Basically that wide trading range will probably hold for a considerable period of time," she added.

To see the full interview with Louise Yamada on what's next for crude oil, watch the above video.

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