Heat and Pressure is how we break down oil into smaller , lighter components in our refineries
They use catalysts also. Take trash and heat and compress it make oil also.http://www.freerepublic.com/focus/f-news/967192/posts
Catalysts lower the energy required or accelerate the same chemical reaction. It is still heat and pressure breaking down oil. The catalysts just make it less expensive.
http://www.britannica.com/EBchecked/topic/99128/catalyst