Changes

====Evaporites====

====Evaporites====

Individual evaporitic minerals (such as anhydrite, halite, sylvite, and carnallite) have well-defined densities and generate straight-line density logs with little variation ([[:file:quick-look-lithology-from-logs_fig2.png|Figure 2]]).

Individual evaporitic minerals (such as anhydrite, halite, sylvite, and carnallite) have well-defined densities and generate straight-line [[density logs]] with little variation ([[:file:quick-look-lithology-from-logs_fig2.png|Figure 2]]).

====Coal====

====Coal====

==Neutron and density logs combined==

==Neutron and density logs combined==

Neutron and density logs each react to both lithology and porosity, so by analyzing the two logs together, one can begin to distinguish lithology from porosity. Neutron and density logs, together with a caliper measurement recorded by the density tool and a natural gamma ray log, are commonly run as a combination. This is the most powerful of the commonly available log suites for general purpose determination of lithology.

Neutron and [[density logs]] each react to both lithology and porosity, so by analyzing the two logs together, one can begin to distinguish lithology from porosity. Neutron and density logs, together with a caliper measurement recorded by the density tool and a natural gamma ray log, are commonly run as a combination. This is the most powerful of the commonly available log suites for general purpose determination of lithology.

===Crossplotting===

===Crossplotting===

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On these scales, any offset of neutron and density logs is maintained regardless of porosity. Offsets are due to rock differences in density and neutron-absorbing properties (capture [[cross section]]). Ideal relationships for the three main liquid-filled porous rocks are as follows:

On these scales, any offset of neutron and [[density logs]] is maintained regardless of porosity. Offsets are due to rock differences in density and neutron-absorbing properties (capture [[cross section]]). Ideal relationships for the three main liquid-filled porous rocks are as follows:

====Sandstone====

====Sandstone====