| Title | Swanhild: Numerical Pressure Transient Analysis Using the Volsung Geothermal Reservoir Simulation Package |
|---|---|
| Authors | K. McLean, P. Franz and J. Clearwater |
| Year | 2020 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | Swanhild, Volsung, well testing, pressure transient analysis, numerical |
| Abstract | The need for numerical models for geothermal pressure transient analysis (PTA) has been long recognised. Until recently the only tools/software available for PTA in the geothermal industry have been based on analytical models, which are too simplistic to represent geothermal wells. The lack of numerical tools for PTA led to the creation of the numerical PTA framework (McLean and Zarrouk, 2017), which is a set of guidelines on how to set up and run numerical PTA models using TOUGH2 and Python. Analysis of the model results and comparison to field data required skills in writing auxiliary computer scripts by the individual reservoir engineer. Despite assistance from the many functions built into Python, numerical PTA was still relatively time-consuming and cumbersome to perform. Specialized software was necessary to bridge this gap, and hence Swanhild was developed, based on the numerical PTA framework guidelines. This study presents testing of the new Swanhild software application. Swanhild forms part of the Volsung geothermal reservoir simulation package and is specifically designed to run numerical PTA simulations using the standardised approach as specified by the numerical PTA framework. The application makes numerical PTA straightforward, including model setup and inversion with field data. The model matching can be performed manually or automated using non-linear regression. A comparison between Swanhild and the TOUGH2/Python implementation of the numerical PTA framework across a range of model parameters reveals no practical difference in the model results, thus validating Swanhild for use in numerical PTA. Software licenses for Swanhild are available for free as part of an ongoing effort to enable and promote quality PTA in geothermal wells. |