| Title | Technical Considerations of Well Design and Equipment Selection for High Temperature Applications – a Canadian Perspective |
|---|---|
| Authors | M. Droessler, B. Curkan, K. Hamilton |
| Year | 2016 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | Geothermal, High Temperature, Thermal Well Design, Casing, Premium Connections, Strain-Based Design, Artificial Lift, Electric Submersible Pump, Reliability, Enhanced Oil Recovery, Western Canada. |
| Abstract | The severe environments of high-temperature geothermal wells can pose a significant challenge in terms of well integrity, equipment performance, and reliability. Many of these challenges have also been faced by thermal oil recovery well operators in Western Canada; where high pressure steam as hot as 350°C is injected into relatively shallow reservoirs to mobilize the highly viscous heavy oil. Given the nature of thermal oil recovery operations, well integrity is of critical importance to operators. Many thermal wells are run into relatively shallow reservoirs (500-1,000 m depth); thus, well barriers must be properly designed to prevent uncontrolled releases of reservoir fluids above the cap rock into potable aquifers and/or to surface. Cemented production casing strings are designed with the understanding that they will plastically deform under high temperature conditions as a result of axial confinement. Strain-based tubular design and the use of specially-designed premium connections for high-temperature applications in accordance with ISO/PAS 12835:2013 have become industry recommended practices in Western Canadian thermal operations. Another key aspect of well performance for thermal well operators is the high-temperature performance and reliability of the artificial lift equipment installed in those wells. Significant strides have been made in the development of improved technologies for producing fluids in thermal oil recovery environments. These efforts are still ongoing, and have already resulted in improved capabilities and reliability of thermal artificial lift equipment. Though technology gaps still exist, adapting thermal artificial lift equipment to the geothermal industry has the potential to advance geothermal power production. This paper highlights some of the fundamental thermal well design and artificial lift developments that have occurred over the past 30 years in Western Canada, and demonstrate how these developments may be applied to geothermal applications. |