问答题 翻译：Proper planning of any drilling venture is the key to optimizing operations and minimizing expenditures.

问答题 翻译：Petroleum may be defined as a naturally occuring, complex mixture of hydrocarbons which may be either gas, liquid, or solid, depending on its own unique composition and the pressure and temperature at which it is confined.

问答题 翻译：For an oil reservoir, as pressure decreases with production, a value is reached at which a portion of the liquid vaporizes to produce a gas phase that then exists in equilibrium with liquid.