Chap. 4] GEOPHYSICAL METHODS IN OIL EXPLORATION 



45 



a new territory it is still advisable to start with, and work away from, 

 known conditions. If the type structure to be encountered in a given 

 area is known, a selection of the most advantageous method is much 

 facilitated. In Fig. 4-1 a schematic representation of reconnaissance and 



Anfic/ines 

 Dome} 



Monodinei 

 Terraces 



Tect- 

 onic 



Soft 



duried 

 eidge 





Volcanic 



Lens 



Faults 



Salt 

 Oomes 



5ali 

 Anticlinei 



Granite 



Rid(]es 



Other 

 burie4 topof- 

 nfhic fedures 



Intrusions 

 Oikes 



Shoesfrinfi 

 etc 



In Wells 



From Surface 



ffiuijyii)^Vr!i.f)»f)f*iMi\\ 



^''^^^^Ott In (^ 



pw^rivii!S/'^m^>& 



ChoKrfoi 



— Detail 



Mo^nef/c 

 Qravimeter 

 tPetfecf/on 5eismic 

 i?efmction Seismic 

 Torsion Balance 

 iPeiistn/ttt/, inductive 



/Reflection Seismic 

 Torsion Botonce 

 Magnetic 

 Refraction Seismic 

 l^esisti\/iti/, tnductive 

 das Survei/ 



dravimefer 

 Torsion daJonce 

 Pe fraction Seismic 

 Reflection 5eisa7ic 

 PesistinA/, Inductive 



Magnetic 

 Gravimeter 

 Torsion Balance 

 Reflection Seismic 



Maqnetic 

 Torsion Balance 

 Reflection Seismic 



Magnetic (?) 

 Resist Mfijft) 



fleciricai Coring 



I 5oit66asJlnattfSis(?) 

 Z Resist! \nt^ (?) 



Fig. 4-L Geophysical methods in oil exploration. 



detail methods for definite geologic conditions is given. Oil structures are 

 divided into the better-known types of tectonic, volcanic, salt, and buried- 

 ridge structures, with schematic illustration of the geologic forms. It is 

 seen that for the tectonic-type structure the magnetic method is first choice 



