Sorgenia Geothermal has been recently awarded some exploration licenses in Southern Tuscany, near the geothermal fields of Bagnore and Piancastagnaio, around the Mt. Amiata volcano complex. In order to successfully locate the first deep wells, an integrated exploration program has been developed, firstly based on a complete collection and analysis of existing critical data, which include mining data, previously drilled geothermal wells data and some geophysical data (gradient wells data, gravimetric data, geoelectrical data, CROP 18B and SIF 12–15/87 seismic reflection raw data). The available seismic data have been reprocessed in order to better focus on the geothermal target and at the same time a new planned 2D seismic reflection survey (approx. 50 km) will be carried out in 2014 to achieve the best coverage in the areas under exploration. An MT survey has been carefully designed and performed (250 stations) considering the severe increase of EM noise in the areas. Geological and hydrogeological surveys, as well as the soil CO2 degassing measurements, a useful tool in confirming the existence of a deep-seated active geothermal system, have been also carried out. The whole dataset has been uploaded and analyzed in a dedicated geodatabase and 2D gravimetric modeling has been performed. Subsequently, the 3D structural model of the area, mainly based on the 3D resistivity and gravity models properly calibrated with wells data, has been shaped and utilized as the basis of the 3D thermofluid-dynamic model of the existing reservoir. Hydrothermal circulation has been modelled using the THOUGH2 code (simulation of multi-dimensional, multiphase and multi component flow and heat transport in porous and fractured media), a useful tool for the assessment of the geothermal potential and for the prediction of the evolution of the system. This integrated approach contributes to substantially reduce the mining risk in deep geothermal exploration, leading to the building of a better-defined conceptual model of the geothermal reservoir towards a more precise resource detection and assessment for the most appropriate and sustainable exploitation of the field.
Integrated Approach for a Successful Geothermal Wells Location in the Mt. Amiata Area (Southern Tuscany)
FULIGNATI, PAOLO;MARIANELLI, PAOLA;SBRANA, ALESSANDRO;
2015-01-01
Abstract
Sorgenia Geothermal has been recently awarded some exploration licenses in Southern Tuscany, near the geothermal fields of Bagnore and Piancastagnaio, around the Mt. Amiata volcano complex. In order to successfully locate the first deep wells, an integrated exploration program has been developed, firstly based on a complete collection and analysis of existing critical data, which include mining data, previously drilled geothermal wells data and some geophysical data (gradient wells data, gravimetric data, geoelectrical data, CROP 18B and SIF 12–15/87 seismic reflection raw data). The available seismic data have been reprocessed in order to better focus on the geothermal target and at the same time a new planned 2D seismic reflection survey (approx. 50 km) will be carried out in 2014 to achieve the best coverage in the areas under exploration. An MT survey has been carefully designed and performed (250 stations) considering the severe increase of EM noise in the areas. Geological and hydrogeological surveys, as well as the soil CO2 degassing measurements, a useful tool in confirming the existence of a deep-seated active geothermal system, have been also carried out. The whole dataset has been uploaded and analyzed in a dedicated geodatabase and 2D gravimetric modeling has been performed. Subsequently, the 3D structural model of the area, mainly based on the 3D resistivity and gravity models properly calibrated with wells data, has been shaped and utilized as the basis of the 3D thermofluid-dynamic model of the existing reservoir. Hydrothermal circulation has been modelled using the THOUGH2 code (simulation of multi-dimensional, multiphase and multi component flow and heat transport in porous and fractured media), a useful tool for the assessment of the geothermal potential and for the prediction of the evolution of the system. This integrated approach contributes to substantially reduce the mining risk in deep geothermal exploration, leading to the building of a better-defined conceptual model of the geothermal reservoir towards a more precise resource detection and assessment for the most appropriate and sustainable exploitation of the field.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
