The endless cash provided by the capture of an Oil Derrick made these buildings valuable targets for all commanders, and they provided the flashpoint for many vicious skirmishes. Once captured Oil Derricks were often zealously protected, lest it be captured by the enemy or simply destroyed. Some oil derricks are deployed over water. They also give a 500 credit bonus with 15 credit per second income. If captured by enemies or co-commanders they get $1000.