A Forward Modeling Approach for Interpreting Impeller Flow Logs
Article first published online: 24 JUL 2009
Copyright © 2009 The Author(s). Journal compilation © 2009 National Ground Water Association
Volume 48, Issue 1, pages 79–91, January/February 2010
How to Cite
Parker, A. H., West, L. J., Odling, N. E. and Bown, R. T. (2010), A Forward Modeling Approach for Interpreting Impeller Flow Logs. Ground Water, 48: 79–91. doi: 10.1111/j.1745-6584.2009.00600.x
- Issue published online: 23 DEC 2009
- Article first published online: 24 JUL 2009
- Received September 2008, accepted May 2009.
A rigorous and practical approach for interpretation of impeller flow log data to determine vertical variations in hydraulic conductivity is presented and applied to two well logs from a Chalk aquifer in England. Impeller flow logging involves measuring vertical flow speed in a pumped well and using changes in flow with depth to infer the locations and magnitudes of inflows into the well. However, the measured flow logs are typically noisy, which leads to spurious hydraulic conductivity values where simplistic interpretation approaches are applied. In this study, a new method for interpretation is presented, which first defines a series of physical models for hydraulic conductivity variation with depth and then fits the models to the data, using a regression technique. Some of the models will be rejected as they are physically unrealistic. The best model is then selected from the remaining models using a maximum likelihood approach. This balances model complexity against fit, for example, using Akaike's Information Criterion.