To identify a petroleum system, the explorationist must find some petroleum. Any quantity of petroleum, no matter how small, is proof of a petroleum system. An oil or gas seep, a show of oil or gas in a well, or an oil or gas accumulation demonstrates the presence of a petroleum system.
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To identify a petroleum system, the explorationist must find some petroleum. Any quantity of petroleum, no matter how small, is proof of a petroleum system. An oil or gas seep, a show of oil or gas in a well, or an oil or gas [[accumulation]] demonstrates the presence of a petroleum system.