66 



p. N, KROPOTKIN 



The absence of any connection between the locahzation of petroleum and the 

 distribution of biogenic organic substances is evidenced by the fact that the coal 

 basins and large deposits of bituminous rocks of the combustible shale type 

 (Scotland, Tasmania, Sweden, Estonia, and others) are, in the overwhelming 

 majority of cases, not oil-bearing districts of industrial importance. And if in 

 some of such districts, like the Urals and Pennsylvania, petroleum is met, its 

 distribution in the vertical direction is traced much lower than the layers rich 

 in organic substances, and, consequently, must have another source. 



THE VERTICAL RANGE 

 OF HYDROCARBON MIGRATION 



The vertical distribution of petroleum and gas also indicates a much wider 

 range of hydrocarbon migration than accepted in different variations of the 



Fig. I. An example of the connections between oil deposits and dislocations 



of the basement and sedimentary cover of the tectonic platform: oil field of 



El Dorado, Kansas, U.S.A. 



Vertical section: the vertical scale is considerably more than the horizontal (cited 

 by Moore from Ver Viebe, 1950). 1 — drill holes; 2 — Pennsylvanian rocks (C3); 

 3 — Mississippian sediments (limestone Ci); 4 — Ordovician sediments (S); 

 5 — granites of the pre-Cambrian crystalUne basement; 6 — Stapleton oil zone in 

 the lower Palaeozoic rocks. 



organic theory. The secondary nature of oil pools usually does not raise any 

 doubt. 



I. O. Brod pointed out that 'if we are to understand as primary deposits those 

 which originated in situ, then we must state that such deposits do not exist at 

 air [18]. Obvious structural geological and hthological evidence is always found 

 to show that these hydrocarbons came to the reservoir rocks not only after the 

 formation of the rocks bearing them, but after the rocks have undergone the 

 action of tectonic forces (fractured, flexed and folded). Asphalts and asphaltites 



