406 



Subsurface Geologic Methods 



Rt 



SZL 



Apporent 

 Resistivities 



MicroLog 



2" (• l"xl" 



im 



Rjj - specific resistivity 



of the ground at distance x 



Resistivity of 

 invaded zone 



^ 



Rf - Uncontaminated zone 



6" 12" X 



Distances from pad 



Figure 183a. Permeable bed (salt-water-bearing) with moderate invasion by mud 

 filtrate (category Pa). Rt < Rr^ 



Rf 



Apparent 

 Resistivities 



MicroLog 

 2" I" fxf 



IBM 



R^ — specific resistivity 



of the ground at distance x 



invaded zone 



JRnfx^. !^R| — Uncontaminated zone 

 mud cofer — 



6" 12" ^ 



Olstonces from pad 



Figure 183b. Permeable bed (salt-water-bearing) with little invasion by mud filtrate 



(category Pi). Rt < Ri 



E3_ 



Apparent 



Resistivities 



MicroLog 



2" I" l"xl" 



lU 



R^ - specific resistivity 



of the ground at distance x 



f^Xn invaded zone 



*.j-L-__'v L/Rf " Uncontaminated zone 

 mud cakg' r , ■ 



6" 12" X 



Distances from pad 



Figure 183c. Permeable bed (salt-water-bearing) with very little invasion by mud 

 filtrate (category Pi). Rt < Ri„ 



