FACTORS GOVERKING THE INDUSTRY 607 



with which oil comes into competition, personnel of the operators, relation 

 of the government to the industry, etcetera. 



Natural Factors and their related Problems 



ORIGIN 



Probably the most enticing subject from a scientific viewpoint, as well 

 as the most unsatisfactory, in connection with petroleum is that of its 

 origin. Many theories have been advanced to account for it, but as yet 

 no absolute proof has been brought forward in substantiation of any par- 

 ticular one. The most commonly accepted theory is that petroleum is 

 derived through more or less tedious processes from organic remains, 

 either animal or vegetable, or both, laid down under water, usually in 

 intimate association with limestone or fine shale-forming sediments. The 

 alteration of this material to crude oil is accomplished through the agency 

 of bacteria and types of distillation and filtration under moderate tem- 

 peratures. Another problem related to that of origin is the one having 

 to do with the character of the oil, whether it be of asphalt or paraffin 

 base. Both problems involve a consideration of complex factors. 



MIGRATION AND ACCUMULATION 



The problems of migration and accumulation of oil should tempt the 

 lithologist as well as the geophysicist and the structural geologist. It is 

 well known that water influences the migration and accumulation of 

 liquid hydrocarbons, and that the structure is also an important factor; 

 but it is only recently that the great influence of even minor changes in 

 the lithology of the containing strata has been recognized. Other factors 

 affecting migration and accumulation are the character of the oil and 

 rock pressure, either hydrostatic, hydraulic, or due to gas. Naturally all 

 of these factors are intimately related, and one can no more isolate a 

 single factor for study than he can expect to study geology intelligently 

 without a knowledge of physics and chemistry. 



CHEMICAL AND PHYSICAL PROPERTIES 



The study of the chemical and physical properties of petroleum, in- 

 cluding as it does the innumerable problems of the refining industry, is 

 a science in itself. Its importance may well be imagined from a brief 

 survey of the following, among other of the characteristics of petroleum. 

 Crude oil is a mixture of a number of chemical compounds consisting of 

 about 84 to 86 per cent of carbon, 11.5 to 14.5 per cent of hydrogen, and 

 minor quantities of nitrogen, oxygen, and sulphur. It is usually a fluid 



