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.

翻譯：For example ,the determination of the pump-setting depth and size of plunger that will lead to the maximum pumping rate in a particular well is a problem of considerable difficulty, which even today has not been fully or saris factorial solved; another interesting problem is that of gas anchors(bottom-hole separators); yet another is the interpretation of the results obtained form devices for determining the depth of the fluid level in the annulus during pumping.

翻譯：A paraffin base crude is an oil whose chief components are paraffins, and which completely distilled, leaves a solid residue of wax. An asphalt base crude is an oil composed primarily of cyclic compounds (mostly naphthenes) which, when distilled, leaves a solid residue of asphalt. Oils which fall in the middle of these categrories are classified as mixed base.

翻譯：It has been suggested that an effective oil source rock generates 10-40 bbl or oil per acre ft (0.0013-0.0052 cc/cc) for each one per cent of organic carbon. This is approximately 500-2000 ppm by weight.

翻譯：the fluid must be identified by direct measurement of certain properties. These measurements involve securing samples of the fluids from the field. The simplest procedure is to make measurements of the properties of the produced fluids. The API gravity of stock-tank oil and the producing gas-oil ratio are routinely determined. The gas-oil ratio is ordinarily the ratio of volume, in standard cubic feet, of gas from the separator to the volume of stock tank oil both measured over the same time interval. If good field practice is followed, the gravity of the separator gas is determined. These data, together with estimates or observations of the reservoir pressure and temperature, can be used to estimate the properties of the reservoir fluids. Such estimates may be of limited accuracy.

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：crude petroleum is not an equilibrium mixture, and on a geological time scale its composition is slowly changing. S.R.silverman found that heating at 121C for two weeks caused detectable changes, the low-molecular-weight components formed being isotopically lighter so far as the carbon was concerned, than the original.

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：Other additives are often added to the fracturing fluids for special proposes. Corrosion inhibitors may be used if the fracturing fluids might cause corrosion in the tubular goods in the well.Other additives are used to make the part of the fracturing fluid which is moving against the pipe walls behave almost like lubricating oil while the remaining fracturing fluid take an almost solid form to carry the maximum amount of proppant.

翻譯：In these early days, as lamp oil, was the important product and the main objects of refining was to extract as much of it as possible from the crude. Lubricants and some fuel oil were also sold, but gasoline was burnt off as unwanted and bitumen was also largely useless.