Subgerencia de Estudios GPG
Pulido C.L.,Subgerencia de Estudios GPG |
Soto Peredo J.,Subgerencia de Estudios GPG |
Guzman H.P.,Subgerencia de Estudios GPG |
Leon H.D.,Subgerencia de Estudios GPG |
Esquivias H.P.,Oficina Geologia y Geofisica Residencia de Estudios RLA
Geotermia | Year: 2013
The application of well seismic technology has been developed mainly for the oil industry, but in this case it has been applied for the geothermal wells to obtain information about velocity and structural data of the area nearby the well. Performing the seismic log requires as an initial step the evaluation of the acquisition feasibility under the specific well conditions and the geological characteristics of the area. The second step is the log design, in which the geometry to be used is selected, such as the number of sensors and the source parameters through the use of a vibrosismo truck. The last step is processing and interpretation of results. In this case, a vertical seismic profile (VSP) through the performance of two processes (first ZVSP and second OVSP) in the injector well AZ-03 at Los Azufres Geothermal Field, Michoacán. The goal was to obtain a side image of the well and mapping the geological structure known as El Chino. The ZVSP registry was built based in the structural section model and the measured speeds of the P wave, to "illuminate" the area surrounding the well. For the OVSP log, the source was located in the platform of well AZ-54 getting a side image to the north of the injector well AZ-03, with 500m coverage in the interest zone. Side discontinuities have been identified close to the AZ-03 well: between 600m and 1350m depth fracture belonging to the east to north fracture system; fracturing through 1350m 1950m depth; and from 2000m to 2600m depth the El Chino structural fault system. The VSP log results indicated that this type of log could be a good tool to support exploration tasks and well sitting, because allows the identification of fault and structural systems underground in geothermal places where no visible structural evidence is detected at surface. Besides, it is an additional technique to input information in the development of conceptual geothermal models and in the location of new production and injection wells.