An apparatus for determining the conditions of a pipeline and for the analysis of the fluid contained therein comprising: a central body having a substantially cylindrical form perforated for the whole length and comprising at least a salinity sensor and at least a pH measurement sensor; a first crown of petals connected to the central body, wherein each petal extends from the central body until it touches the internal wall of the pipeline and wherein each petal comprises at least one deformation sensor and at least one roughness sensor; a sliding device integrally connected to the central body in a more advanced position with respect to the first crown of petals, wherein the sliding device can be a second crown of petals identical to the first crown of petals or a foam pig suitably perforated. A method is for determining the conditions of a pipeline and for the analysis of the fluid contained therein, which uses the apparatus.