Abstract: In a method and apparatus for obtaining a recording of facies of geological formations, logging instruments are moved in a borehole to produce log measurements at successive levels of the borehole. With each level is associated a reference sample whose coordinates are constituted by the respective measurements in a multidimensional space defined by the different logs. The scatter of samples thus obtained is analyzed to distinguish modes characteristic of clusters in which the concentration of samples is the highest. The samples may then be associated with selected modes to form classes each characteristic of a respective facie, and the facies then displayed as a function of the depth of the respective associated sample.