| Title | Analysis of Field Case in Salamander-1 Geothermal Well |
|---|---|
| Authors | Alexander BADALYAN, Themis CARAGEORGOS, Zhenjiang YOU, Ulrike SCHACHT, Pavel BEDRIKOVETSKY, Chris MATTHEWS, and Martin HAND |
| Year | 2013 |
| Conference | Australian Geothermal Energy Conference |
| Keywords | Salamander-1 geothermal well, field case, formation damage, fines migration |
| Abstract | Analysis of Salamander-1 geothermal well performance for possible formation damage necessitates laboratory tests on its rock materials. Information available from other wells from the same formation indicates that rock deformation and fines migration may contribute to the formation damage. Estimation of these reasons was complicated by unavailability of cores from the well for laboratory analysis. A novel method for prediction of formation damage from cuttings is proposed. It is especially important when rock cores are not available. According to this method, rock cores from another well, Ladbroke Grove-1 from the same formation, were used in the laboratory study for the evaluation of the effect of effective stress on their liquid permeability, and for velocity- and salinity-induced fines migration which may result in formation damage. Fines migration tests were carried out on a composite porous media including fragments from Ladbroke Grove-1 and Salamander-1 wells. Sandstone core deformation doesn’t significantly affect core permeability and doesn’t contribute to formation damage. Significant initial reduction of cores permeability was due to fines mobilisation at various velocities of high salinity water. Further formation damage was caused by flow of low salinity water. Similar fines migration results were obtained for composite porous samples with fragments. Scanning Electron Microscopy identified clays (kaolinite and chlorite) as major minerals in collected fines. Application of Derjaguin-Landau-Verwey-Overbeek (DLVO) theory shows that decrease of water salinity to values similar to those for discharge and reservoir water creates a strong repulsion force between clay particles and sand. This results in fines mobilisation, their transport through porous media, capture by smaller pores and formation damage. Good correlation of fines migration data for cores and fragments from Ladbroke Grove-1 well successfully validates the proposed methodology. |