Analysis and Interpretation of Environment Sequence Models in the Triassic Province of Algeria

The Saharan Triassic consisted of varied continental environments, namely, fluvial, flood plain, lake, Sebkha, and wind. In such a context, and during the periods of no deposition, physicochemical phenomena related to the climate and type of bedrock occur, leading to the formation of a more or less advanced ground related to the elapsed time between two phases of sedimentation. In the Saharan Triassic the context is different; however, one nevertheless finds the same expressions along with additional ones: silcrête, gypscrête, and calcrête. The formation models recognized on the level of the wells at Hassi R'Mel field are representative primarily of formations filled with siliciclastic, eruptive sediments and evaporate-type saliferous shale deposits. The top of the stratigraphic sequences is represented by discontinuities, modifications related to the pedogenesis and not characterized in the old models. This work therefore attempts to refine the above models by using a diagraph-based modeling approach (Gamma ray, neutron, sonic, density and resistivity) to examine the evolution of sequences. Lithography findings obtained using the results of faciologic analysis established for this purpose on the level of the Hassi R'Mel field are also used.