Subsurface Geologic Methods 



SUBSURFACE GEOLOGY 



St rafigrophy 



Structural 

 Geology 



Geophysics 



Economics 



Petroleum Production 



Engineering Engineering 



I I Development I I 

 Engineering 



Sedimentology 



Sedimentogrophy 



Petrogrophy 



Paleontology 



Detritol 

 MInerology 



Figure 1. Subsurface geology and its relationship to other sciences. 



The subsurface geologist should be familiar with all techniques that 

 assist in determining subsurface phenomena and should recognize limita- 

 tions of these methods. 



Some 25,000 wells drilled each year add new sources of geological data 

 requiring close study by specialists in petrology, paleontology, stratigraphy, 

 geochemistry, geophysics, and structure who have the responsibility of deter- 

 mining correct regional correlations, suitable classification of the rock se- 

 quences, isopach and paleogeologic maps, faunal and floral zones, facies 

 changes, vertical and lateral extent of oil- and gas-bearing zones, character 



Figure 2. Correlation between some of the duties of the subsurface geologist and 



petroleum engineer. 



