翻譯：The first step in planning a well should be the gathering of all available data on past wells. In this respect it is important to be completely familiar with all sources of information, the availability of the sources, and the information normally associated with each source.

翻譯：After the casing string is run, the next task is cementing the casing in place. An oil well cementing service company is usually called in for this job although, as when casing is run,the rig crew is available to lend assistance.

翻譯：In addition to being useful as an exploration tool, subsurface maps are a necessary part of any reservoir engineering study; and petroleum engineers, as well as geologists, must be completely familiar with their construction and interpretation.

翻譯：The fluids of a petroleum reservoir are generally gas, oil, and water in varying proportions. Each phase can differ widely in composition and properties. Gas and oil, either as separate fluids or in mixtures, change their state or phase as reservoir pressure changes.

翻譯：A major oil company usually initiates the sequence of events that leads to the drilling of oil and gas wells in foreign fields, but independent oil operators pay for most of the wells in the United States. In fact, about 80% of all wells drilled in the U.S. today are financed by independents.