D H 



Figure 28. A, B — Structural traps. C — Differential compaction over buried compe- 

 tent rocks, which produces flexures in overlying strata. The reservoirs shown are 

 controlled by both the structural and stratigraphical factor. D, E — Combination 

 of structural and stratigraphic conditions accounting for the accumulations. F — 

 Salt intrusions commonly arch the overlying strata thus permitting accumulation 

 of oil and gas at various points in the structure. G — Igneous intrusions into 

 sedimentary sections, which sometimes induce secondary permeability in the host 

 strata and develop favorable reservoir conditions. H — Progressive overlap which 

 gives rise to favorable stratigraphic reservoir traps; accumulation may be 

 erratically distributed. 



