A couple points....
Refiners usually plan shutdowns for the winter due to lower crack spreads (lower profit) and avoid shutdowns in the summer like the plague. In-fact we have had a couple clients push back summer planned T/A's this year because some crack spreads are quite favorable right now. The crack spread prior to the shutdown was obscenely high at $26 (per Reuters), people get fired for losing production during such a favorable environment. Post- emergency shutdown the crack spread only increased to $28, a temporary 8% increase for BP Whiting's competitor's while a 100% decrease for them.
Secondly, unplanned emergency shutdowns cost absurd amounts of money. Maintenance is usually planned 2-3 years in advance for a T/A, having to bring contractors on-site immediately and respond to an emergency requires intense premiums.
Finally, there are at least 59 refining corporations in the USA, a significant number of which have no upstream production whatsoever and therefore are not directly effected by your extraction cost discussion. I'm referring to parent corporations, there are even more individual companies and then again even more individual refineries. If you want to include chemical plants and other associated facilities, the number increases dramatically. Furthermore, these 59 corporations operate in a number of more or less isolated regions, there are quite a few crack spread metrics because it varies so dramatically around the country.
Now I've never met with executives from any of the 59 corporations, but having been in meetings with engineers whom are refinery managers the idea that there is collusion between these 59 corporations to the extent that someone is willing to break their facility during a $26 crack spread environment to give their competitor's an extra $2 spread is laughable.
Feel free to ignore any/all of the above and continue along with conspiracy theories.
http://www.reuters.com/article/2015/08/11/refinery-operation-bp-whiting-idUSL1N10M15N20150811