^(IV^ t'A ^"loTl^ ?^ geological traps: Reservoir beds are - 

 (A) arched, (B) faulted, or (C) pierced by shale or salt 

 domes; they also may occur where (D) fossil reefs intrude 

 or (E) the sediment wedges out at unconformities 

 (Source: Reference 8). 



level 



Anticline or dome 



level 



'•fault 



Fault 



EXPLANATION 



Oil zone 



Impermeable layers, 

 commonly shale 



Fi-:-:":-j shale 



I : : : : I Sandstone 



Salt dome 



17 



