I'd like here to give a brief talk about the above Petroleum Eng. type of work.
Generally speaking the word Petrophysicist (PP) came to exist in 1950s when the Shell electrical Eng. Archie wrote a paper about calculating formation water saturation from resistivity. Indeed, he was the father of PPs. in general, PPs are those who seek to measure fluid and rock properties such as (porosity, permeability, saturation ......est.) form wireline or pipe convey measurement or cores. Mainly, there types of measurement are required so that PPs can do their job, electrical measurements, acoustic measurement and nuclear measurement.
Basically, all the three types of measurement will give physical properties either for the rock or the fluid or the fluid being contained in the pore space in the rock and sometimes the mud used in drilling. For example, all resistivity typed tools are categorized in three main types, and these are: laterlog, Microresistivity and induction tool. Each type of these has certain limit and can be run in specific borehole environment such as type of mud, water base mud or oil based mud and the range of resistivity and Rmf/Rw ratio. I’ll continue the rest later