Chemostrat
Litho-typing
The use of turbine drilling can results in rock flour being produced from the wellbore, this rock flour leads to difficulties in identifying the lithology present with the formations drilled.
By looking at the chemistry of the rock flour the original lithology can be reproduced. For instance in carbonate sequences by looking at the proportions of Calcium (ca), Sulphur (S) and Magnesium (Mg) the % of Carbonate, Anhydrite and Dolomite can be deduced to provide a classification of the original lithology.
The technique can be applied to Carbonates and Clastics and can even be used to predict things like the sand/shale ratio in sequences where the Gamma response is skewed by K-feldpar abundance.