问答题 翻译：The main function of a rotary rig is to drill a hole, or as it is known in the industry, to make hole.

问答题 翻译：Finally, it should be noted that the effective compressibility of an oil-gas mixture below its bubble point pressure is large, since much of the volume decrease with pressure increase is associated with the change in phase of some the gas to a liquid.

问答题 翻译：The gas formation volume factor Bg is the volume measured at reservoir conditions that corresponds to a unit volume of gas at standard conditions. Thus, Bg<1.