Optimal Well Placement in the Theistareykir Geothermal Field for the Next Well in Succession
Author: Basil Alexander Jefferies
Year: 2016
Supervisor: Ágúst Valfells & Egill Júlíusson
The project was conducted in cooperation with Landsvirkjun.
Abstract
The Theistareykir field is one of many high-temperature geothermal fields in Iceland. The development of a 90 MW power station is planned for Theistareykir to connect to the national grid for this expanding demand throughout the country. The first 45 MW is expected to begin operation of by fall of 2017, with the second 45 MW installation by as early as spring of 2018. Since Theistareykir has had several decades of surface and subsurface studies performed it is expected to be able fit the demand based on results from a conceptual and numerical model that have since been generated. The TOUGH2 reservoir simulation code was used in the following study, along with the reservoir's numerical model to assess optimal well location and output potential for an additional well proposed to be added to the field. This location was determined by simulating individually 476 cells within the field and basing calculations on the 178 which successfully ran to the 10 year point. Of those, 48 files ran fully to 30 years and were included in a second trial simulation period. Applying the results of MWh generation to a profit calculator and then discounting, the NPV results of both trials were ordered to show the highest grossing wells. Three result maps were generated in order to locate trends among the output from each cell in the trials. According to the final results, the optimal location for a well would be within cell 533 as it proved to be advantageous in both trial periods; however the well track for the newly placed ThG-7 pass through here and no feedzone was found to lie within the cell. With some exclusions presented voxels 638 and 743 were then concluded to pose the greatest benefits from the 30 year data set while voxels 538, 657, and 654 grossed highest among the 10 year data. A suggestion is given to update the model with regards to its inclusion of ThG-7, as well as ThG-9 which has not yet been coded for in the model, as it could significantly influence the location of future wells.