NEW YORK (TheStreet) -- Changing prices between oil produced in North Dakota and oil in storage in Cushing, Oklahoma, and on the Gulf coast is starting to positively help some dedicated shale producers, including Continental Resources (CLR) - Get Report, Whiting Petroleum (WLL) - Get Report and Hess (HES) - Get Report.

In the U.S., when we talk about crude oil, we are usually quoting the benchmark West Texas Intermediate (WTI) crude being priced in Cushing. But prices for crude produced in other parts of the U.S. can trade at quite different prices than WTI. In the Bakken shale region of North Dakota, fast increasing production there in the last five years and a need for those barrels to compete with Canadian barrels for transport in pipelines headed south has allowed Bakken crude to trade at a big discount to other U.S. grades, sometimes as much as $12 to $15 dollars a barrel less than WTI.

But the recent drop in the number of rigs being actively used to drill for oil has impacted the Bakken the most. It is here that many of the marginal oil producers that had been working less than prime acreage have been forced to rapidly slow production. Less oil produced in the Bakken has meant less competition for pipeline space and even some relative tightness in supply. This has forced differentials between Bakken and WTI oil to reach close to parity.

So, although oil prices remain very depressed, we have seen an amazing improvement in realized prices in the Bakken thanks to a rally in oil from $45 to about $60 a barrel and a drop in basis differentials closer to zero. That's an almost $30 per barrel increase in realized prices since the worst days of the oil bust -- and that improvement is not being represented yet in the share prices of the big dedicated Bakken producers.

My favorite of these players is Hess, which has also just embarked on an infrastructure asset sale of Bakken pipelines for $2.68 billion to a private equity firm. This joint venture sale is part of the restructuring that Hess has been doing to concentrate on shale assets and oil production. Every time Hess can spin off its remaining infrastructure assets is a value unlocking event for the company and Hess can do many more of these deals going forward.

But mostly, I like the unrealized value that increased oil prices are delivering to these few Bakken oil companies, and think that there is finally some value to be had in these shares. Now could be the time to buy them.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.