Sur les repr\'esentations absolument na\"ives et leur module de Wach

We construct a Wach module for the absolutely semi-stable representations the filtered $(\phi ,N)$-module of which satisfies the Griffiths transversality, which happens in particular for ordinary representations. This construction extends the ones of Wach and Berger for the absolutely crystalline case. We use it in particular to describe semi-stable representations which factor through the Tate curve extension.