Drilling For Oil Assignment

The assignment we did in class was how to find were oil is and were to drill.Things I found interesting was that you need all three of these things to no were oil is,and that 70% of the time when they drill for oil the area is dry,also that even just because the oil smells different it would be sold for less money .Oil cost less because of the smell because it has to go through process to get the smell out so they sell it for less,I got this information from wikipedia.My opinion is that you cant always trust what the map says because of the 70% chance that you wont fined oil.