There is abundant evidence that gas is present in the sediments of the prodelta of the Llobregat River in the area of the Barcelona Port. The presence of gas has been directly observed by gas releases and deflagrations occurring during a site investigation campaign involving boreholes and CPTu tests. Methane has been identified by means of BAT permeameter tests. The record of a CPTu test performed in an area where gas is known to be present has been examined in detail. In spite that there are several features that could be related to the gas presence, it is challenging to identify unambiguously the presence of the gas from the CPTu record alone.