Abstract: A device and method are provided for determining, from a well, the orientation of fractures in a geological formation having a fracture zone. The device includes a tubular element connected to a hydraulic fluid source and having at least one flow orifice through which the fluid may escape. This device further includes:(a) at least one chamber through which the fluid may flow from the tubular element towards the fracture, this chamber being in communication with the flow orifice,(b) at least one mobile orientation element situated substantially at the same depth as the fracture zone, this element being articulated about the tubular element and being adapted for moving by rotation towards a final position following discharge of the fluid from the chamber towards the fracture zone, and(c) an arrangement for locating the final position of said orientation element, this position being in relation with the orientation of the fracture.