The Hidra oil field is located in the Austral Basin, about 13 kilometers off the east coast of Tierra del Fuego Province in southern Argentina, with water depths that range from 20 to 40 meters. It was discovered in 1982 with the drilling of Hidra.x-1 well that found a column of undersaturated oil, and it was afterwards developed in 1989 through two offshore platforms (Hidra North & Hidra Center). During 2020, a synthesis was carried out in the field in order to determine the position of the wateroil contact (WOC). Most drilled wells showed clear evidence of an WOC at –1686 mTVDss, except for the appraisal well Hidra.e-2, which was not in line with this interpreted contact. Without any data suggesting disconnection between Hidra.e-2 and the rest of the wells drilled, a detailed revision of the operations performed during and after drilling was carried out. Well operations such as electrical logging, pressure data and fluid samples, drill stem tests (DSTs), as well as mud weight were analyzed to determine the reliability of the data and their weight in the interpretation. This analysis revealed that the well Hidra.e-2 has evidence of significant mud invasion that affected the resistivity logging and consequently, the water saturation (Sw) interpretation. Mud invasion is supported by the absence of separation between the curves with different depths of investigation (deep and medium resistivity) as well as by the RFT samples which retrieved large amounts of mud filtrate. Also, mud invasion could have produced a gravitational segregation of the fluids near the wellbore that could mimic the presence of a transition zone, however, given the SCALs data available in the core retrieved in this well, the possibility of having an actual transition zone cannot be discarded. This study allowed us not only to challenge the water saturation interpretation of Hid.e-2 well based on the evidence of mud invasion, but also to determine how different operational problems could impact the quality of acquired data. Both the quality and quantity of data remain a complex issue to which geoscientist are normally faced when dealing with mature fields.