Abstract: Oil well always follows the production rate decreasing and the containing water increasing from the beginning of the development to the well closed not until it is no economic value. Especially, it is developed after the middle development term, the crude oil production rate was declined quickly and the contained water was raised quickly. The measurement of the increased
production was necessary for the production decrement to be delayed and the contained water increment to be controlled, it will enhance the life of the oil well economy. The cost will gradually be increased when the oil well is production with the time lose.It will make the economic benefit maximum in the whole oil well life when the oil well benefit was equal to the cost by some
measurements.

Key words: crude oil, production, cost, income, decisionanalysis