| Title | Estimating Individual Injectivity Indices for Two or More Feed-Zones in Geothermal Wells |
|---|---|
| Authors | Þorsteinn EGILSON |
| Year | 2020 |
| Conference | World Geothermal Congress |
| Keywords | Spinner log, fluid velocity, injectivity, feed zone, pressure |
| Abstract | Spinner logs are widely used for feed zone analysis in geothermal wells, both for location and permeability purposes. Traditionally, temperature logs have been used as a major basis for feed zone location and co-interpreted with circulation loss information during the drilling process, qualitative feed zone size has been estimated. In 2012 spinner logs were added to ÃSOR´s logging toolbox for supporting and improving feed zone analysis of geothermal wells. The feed zone analysis scheme introduced is based on a well-known fluid velocity determination with spinner logs and it assumes the same well diameter above and below each feed zone recognized from a change in fluid velocity. Up and down spinner-logs combined with corresponding pressure log at two different flow rates form the basis for a quantitative feed zone analysis to determine the injectivity index of individual feed zones. With a good quality spinner log, added feed zone indices accurately fit the total injectivity index obtained in a conventional injectivity test |