| Title | A 3D Model of the Chachimbiro Geothermal System in Ecuador |
|---|---|
| Authors | Byron PILICITA, Gunnlaugur EINARSSON, MálfrÃður ÓMARSDÓTTIR |
| Year | 2020 |
| Conference | World Geothermal Congress |
| Keywords | modelling, geothermal system, Chachimbiro, petrel |
| Abstract | The Chachimbiro Geothermal System is the most important Geothermal Prospect in Ecuador. Various geothermal models have been presented based upon geological, geochemical and geophysical data collected at different epochs. Currently, Chachimbiro Prospect is ready to enter the exploration drilling phase. This is why it is important to identify the best drilling targets. Petrel allows the combination of all surface exploration data in order to identify different geothermal anomalies and create a 3D model to visualize all features of the system. This model uses lineaments as boundaries of the system based on structural mapping and locations of earthquake epicentres. The heat source is related to magma chambers that feed the main emission centre but is also controlled by faults which influence possible up-flow. This up-flow is located beneath a cap rock (0-10 Ωm) related to a high resistivity core which shows a concave shape (30-70 Ωm). The Na/K geothermometers show temperatures around 240°C, however, the water in Chachimbiro has poor equilibrium with the rock. The resistivity analysis shows possible temperatures from 200 to 250°C, but this range of temperature does not represent the current temperature of the system. The origin of the fluids in Chachimbiro is meteoric based upon isotopic analysis. The interaction between this fluid with the up-flow into the sub-surface forms the possible reservoir. Hot springs and gas manifestations (CO2-H2S) are outflows of the system which also indicate volcanic activity in the system and expressions of the reservoir on the surface. The intersection between Chachimbiro and Azufral faults and the Chachimbiro Fault has been identified as well targets in the system which could be reached by directional drilling from three different locations. These locations have been chosen by combining the structural features, the resistivity anomalies, possible outflow and up-flow zones, the hydrothermal areas and temperature anomalies which were modelled and analysed in Petrel. |