With new oil found in the gulf,Why do they know its going to cost more or the same? Then why look for it ?

All of the answers are somewhat correct....it is your question that makes a presumption that probably isn't all that factual.

The cost of oil is a commodity and traded on the market like your stocks.....the same fears that you have in the market that move a stock up or down....oil prices do the same. Trouble in the middle east speculators trade those options,,,,,Prudhoe Bay Oil Pipeline trouble raises the price. The opposite exists when there are less troubles in the world and the geo-political problems are kept to a minimum. The finding of a big find like in the gulf the market will tend to be soft.

The reason companies search for Oil is to make sure that their business keeps going.....no oil....no gas...no chevron.

The presumption that they know the price is not true as there are a lot of factors that are involved.....they may know what it will cost them to pull that oil out of the ground and the exploration costs associated with that find and come up with a cost based on these figures.....IT WILL NEVER EQUAL EVEN NEAR the $60.00 per barrel today.

That oil is very deep in the ground, and thousands of feet below water, the new price level makes it possible to extract it and make a profit- Same for Oil Shale and Tar sands- we got Oil coming out our behind now, and don't forget, this stops a lot of problems with our balance of trade and dependance on the Mid East.

The price of oil is not set by the cost of producing it. It is set by the market, ie. what buyers are willing to pay for it. People look for it if they expect sell it for more than it costs them to find, pump & refine it.

Supply and Demand. Economics 101.

kind of makes it seem like we're going to run out, doesn't it? if we go looking for more without decreasing prices to do so

OR perhaps it's just so oil companies can make more money.