It was another positive day for oil prices despite weekly inventory numbers showing rises in both gasoline and oil products. Oil prices, which have been in a strong upward trend lately continued to show strength today by trading up $0.45 to $71.86.

The market was given contradictory numbers today from the Energy Department which showed that gasoline inventories climbed by 1.8 million barrels and gasoline inventories rose 3.1 million barrels last week. Analysts had been expecting to see rises, but nowhere need the size that was actually reported. Ahead of today's report, traders were expecting to see gasoline and oil inventories each rise by 300,000 barrels, so today's announced inventory growths were a surprise to say the least.

So if inventories are growing faster than expected why were prices rising today? That's a fair question, and the answer to that question is one of the basic reasons why we have been seeing prices rise all along: American refinery output. As we all know by now, U.S. refineries have been struggling this year to maintain solid output capacity and last week was no different.

In order for refineries to keep up with normal demand, analysts estimate that they need to be running steadily above 90% capacity potential. Last week refineries were able to pick up the pace a little bit, but not nearly what analysts had been hoping to see. Capacity rose to 90%, which was just slightly above the 89.4% we saw the previous week. This was enough to bring the bulls back into the market again today to push prices higher.

Another factor weighing on traders' minds is the current situation that is taking place in Nigeria. Rebels in the country ended a month long truce and openly attacked a Shell oil rig in the country which once again raised concerns over the possibility of future supply disruptions in the area.

Michael Fowlkes has worked as a stock trader for seven years and spent the last two years working as an analyst for the online investment advisory service Investor's Observer.

We have been expecting to see this for a few days now, and today oil was finally able to close the session above the psychological $70 mark at $70.55, gaining $0.98 on the session. Earlier in the day prices were able to trade as high as $71.06 before settling down a bit to head into the weekend.

Today's close above $70 marks the first time in almost a year that prices have been at this level, with the last time oil was above $70 being back in August '06. The primary reasons behind the move today were more of the same that we have seen lately... concerns over gasoline surprises and political tensions around the globe.

American refineries have been the center of attention over the past couple of months with concerns over how well refineries are going to be able to keep up with the growing demand during the peak summer driving months. This week those concerns were once again brought to the surface after the weekly inventory numbers out of the Energy Department showed n unexpected decline in gasoline supplies. Analysts had been expecting to see a rise of 1.1 million barrels when in fact the numbers showed that gasoline stocks fell by 700,000 barrels.

Over the past couple of weeks I have been saying that we would be seeing $70 oil by the end of the month and today we have seen just that. After breaking through the psychological $70 barrier to hit a high on the day of $70.09, prices since have retreated slightly to $69.97

The main reason behind this push above the $70 mark is yesterday's oil inventory report from the Energy Department that showed a drop in gasoline inventories. Gasoline levels have been the center of attention lately since American refineries have been unable to keep production capacity stable above 90% as we head into the peak summer driving months.

Last week we were treated to a massive increase in gasoline supplies, but this week the numbers turned against us once again. Analysts had been expecting to see supplies increase, but what we saw was a decline of 700,000 barrels (analysts had been hoping to see a 1.1 million barrel increase).