Radioactive Marker Technique (RMT), an in-situ method to measure reservoir rock compaction and to evaluate uniaxial compressibility coefficients (C-m), is examined here. Recent field applications seems to confirm that RMT-derived C-m's match with sufficient precision with those calculated from land subsidence observed over the field by means of geodetic surveys, but are not always in good agreement with those derived from lab measurements. In particular here is reported an application of RMT in the Italian Adriatic offshore, which highlights the discrepancies of C-m's measurements from lab and RMT At present, these discrepancies aren't thoroughly understood, so, from an applicative standpoint, it is still necessary to perform, a critical comparison and integration between both set of data.