| Popis: |
Summary This work presents a high-resolution seismic imaging study of a target sulphide mineralization located in the Kylylahti polymetallic mine, Eastern Finland. For this purpose, in-mine VSP measurements were carried out, using two different technologies: a conventional three-component VSP and a fibre-optic Distributed Acoustic Sensing (DAS) system. The two acquisition systems were placed in existing exploration boreholes adjacent to the deposit and successfully recorded reflections from the target and its host rocks. Subsequent application of a target-specific VSP processing and imaging workflow to the conventional and DAS data provided high-resolution reflectivity images from both systems. To support geological interpretation, a 3D seismic forward modelling study was conducted using a geological model created from exploration drilling data and laboratory petrophysical measurements. Cross-validation of the acquired VSP data with the synthetic seismograms and extensive logging data enabled identification of the target reflection as well as interpretation of several new geological contrasts. Between the two VSP methods, the conventional system exhibits slightly superior signal-to-noise ratio and bandwidth. However, the DAS system also provides images of satisfactory quality at much less acquisition time and logistical effort. Thus, DAS offers a powerful and particularly cost-effective exploration technology suitable for detailed delineation of mineral resources. |
