简答题 翻译：Practically every rig uses internal-combustion engines as its prime power source, or its prime mover.

翻译：Also specified in gas purchase contracts is the maximum amount of sulfur the sales gas may contain. 点击查看答案

翻译In general, gas pipelines operate at higher pressure than crude lines; gas is moved through a gas pipeline by compressors rather than by pumps; and path of natural gas to the user is more direct. 点击查看答案