Just because you can get it done this year for $25 a barrel dose not mean that it would not be better to leave it for ten years or more and sell it for $75 per barrel.
Having been involved in this business for decades and at the decision-making level, I can tell you that the decisions to develop are not taken lightly. Most of the companies are public and report to the shareholders. The decisions that are made are in their best interests, not to fill the pockets of a few executive who normally don't own a large proportion of shares. At any given point when you make the decision to develop or not, it is based on an educated view of future prices. I was actually involved in some North Sea acquisitions back when oil was trading in the $20 range years ago. The CEO was adamant that oil would eventually be much, much higher. He was right and as a consequence, the company did quite well. At the same time, someone buying an asset in 2013 is probably not too happy right now. But remember that most of these fields have production contracts that are about 25 years in length. That is a lot of time for price movement and it can be for the good or the bad. After you have made a discovery you have to make your decision based on sketchy projections and the range is quite large. Currently, Raymond James is suggesting Brent prices of $80 next year whereas the World Bank is saying $60, that is a huge discrepancy.
If you knew what the price of oil was going to be next week or next year you could make out like a bandit on the market....unfortunately there as many losers as winners in that game.