I wonder about this as well. I bought more PWE on Nov 1 and bought just a few of HTE at the same time. I wish I had made HTE the big purchase as it is now well above the Nov 1 price while PWE is still significantly below that price.
HTE was a third lower in price than PWE, now they are about 7% lower.
Refining, transport, and collars. The other posts hit the nail on the head. Some of them, like PVX, for example, has worked to get more of the supply chain. So they don't just own the oil-producing land, they also own the pipelines to move the oil, the refineries to process it, the exploration groups, the engineering maintenance support teams, etc. The others are more diversified so they benefit less when oil rises, but make it up when refinery capacity is low, for example.
Finally, PWE is also very focused on the dividends right now. Since they are primarily an oil play, they are more at risk from the volatility in the oil market - not what the shareholders want and not what the company wants when they are still negotiating/lobbying the government. So they have collars that lock in prices and prevent extreme highs or extreme lows for the time being. In some ways they are sacrificing short term profits to protect the dividend long term. (It also has the added benefit of helping them in their lobbying and keeping investors in while they sort through some things.)
In short, PWE is just a different kind of play right now. Not different bad or different good. Just different.
HTE was the one who bought into the refining business last year:
Over the past twelve months Harvest has focused on the development of our asset base through the execution of a large capital program, which has positioned us very well to deliver value creation in the years ahead. We also continued to look for assets that we could acquire at reasonable prices and create value through our hands-on management and investment. On October 19, we closed the acquisition of North Atlantic Refining Limited ("North Atlantic") and became an integrated oil and gas organization. This refining and marketing asset extends our participation in the hydrocarbon value chain, provides attractive financial integration with our upstream business and positions Harvest as a strong and diversified entity within the Canadian oil and gas industry as a whole.