No abstract available

[en] Three types of experiment were performed: a) oil was injected into a water-saturated limestone sample, b) water was injected into an oil-saturated sample, and c) D₂O was injected into a water-saturated sample. The measuring protocol comprised the acquisition of a 1D spectrum, a CPMG experiment to estimate the T₂ relaxation time, and the acquisition of spin-echo images. (orig.)

[en] During its evolution, organic matter may undergo different types of alterations which modify its chemical composition and which can be superimposed on the transformations normally induced by thermal maturation. These alterations are linked to the modification of the oxido-reduction conditions and/or the action of host-rock extraneous solutions. Such effects are for instance observed in the case of several geologically well-known uraniferous deposits where some chemical disequilibrium between the apparent diagenetic state of the organic matter and the diagenesis undergone by the host-rocks can be pointed out. Examples presented herein concern U deposits associated with various types of organic matter. These chemical transformations are connected with three major phenomena: oxidation, biodegradation and aromatization. 97 refs.; 12 figs.; 2 tabs