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：This chapter deals with the fundamental properties of reservoir rocks. The properties discussed are (1) porosity - a measure of the void space in a rock; (2) Permeability - a measure of the fluid transmissivity of a rock; and (3) fluid saturation - a measure of the gross void space occupied by a fluid. These properties constitute a set of fundamental parameters by which the rock may be described quantitatively.

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：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：The application of physics to the study of rocks (geophysics)is very important in petroleum geology. In its broadest application geophysics makes a major contribution to understanding the earths crust and, especially through the application of modern plate tectonic(板塊構(gòu)造)theory, the genesis and petroleum potential of sedimentary basins. More specially, physical concepts are required to understand folds（褶皺）, faults（斷層）, and diapers（底辟）, and hence their roles in petroleum entrapment.

翻譯：If Colonel Drake, Uncle Billy smith , Anthony Lucas , and the untold thousands of other members of the fraternity of drilling pioneers were alive today , they would no doubt be fascinated and amazed by the proliferation of drilling tools and techniques that have been developed since those primitive days in Pennsylvania and Texas . Undoubltly , they would also be impress by the great numbers of drilling rigs at work today-------over two thousand in the USA alone.

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.

翻譯：A portion of the sample is used to determine the gravity of the oil expressed in AIP unit the lighter the oil, the higher the API gravity .In most cases the price paid for the coude is determined in prat by the API gravity, hence ,the importance of careful gravity determination in each instance.

翻譯：The HF-HCI mixture (usually 3-percent HF and 12-percent HCI) then is injected. The HF reacts with calys, sand, drilling mud, or cement filtrate to improve permeability near the well-bore.The HCI will not react and is present to keep the PH low, preventing precipitation of HF reaction products. Sent to keep the PH low, preventing precipitation of HF reaction products.