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：The total quantity of petroleum now thought to exist on Earth is about 14 trillion gallons. In weight that is only one-ninth as much as the total existing quantity of coal and ,at the present moment, petroleum is being used up much more quickly. At the present rate of used, the worlds supply of petroleum may last for only thirty years or so.

翻譯：A porous medium has a permeability of one darcy when a single phase fluid of one centipoise viscosity that completely fills the voids of the medium, will flow through it under conditions of viscous flow at a rate of one cubic centimeter per second per square centimeter cross sectional area under a pressure or equivalent hydraulic gradient of one atmosphere per centimeter.

翻譯：An acidizing treatment for a sandstone formation normally will consist of sequentially injecting three fluids---a preflush, the hydrofluoric acid hydrochloric acid mixture, and an after flush. These fluids serve definite purposes.

翻譯：THE OPEC oil cartel is about to turn 40, and the mood in the run-up to the grand heads-of-state party in Venezuela in less than three weeks time is jubilant. Not quite two years ago,oil was $10 a barrel and the cartel was on the brink of collapse. Now the oil price is well above $30 a barrel, and it shows little sign of coming down.

翻譯：The transportation of oil has also led to the spectacular development of gait ships ,the largest ships that ever sailed the oceans of the world .in the last few years ,since it has been necessary to ship oil from middle East-one of the largest oil producing regions-around the cap of Good Hope in south Africa these tanks has grown to almost unblievable proportions.

翻譯：A reservoir trap is a combination of physical conditions that will cause hydrocarbon liquids and/or gases and water to accumulate in porous and permeable rock and prevent them from escaping either laterally or vertically because of differences in specific gravity, pressure, fluid/gas characteristics, and/or lithology. It has the capability of collection, holding, and yielding hydrocarbon fluids and water.

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：Since the volume factors and the solution gas-oil ratio are determined from laboratory measurements on samples of reservoir fluid at reservoir temperature and various pressures, these parameters are effective substitutes for detailed phase equilibrium data in most production calculations. However, these parameters are unknown at the time that exploration well tests are run, and hence they are estimated from correlation charts.

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.