Bits of diamonds lying around, illuminating the outline of a wellbore in the ground…
Up until now, drilling has been the only means used to extract geothermal heat from the subsurface. Regardless of the type of geothermal system, the heat can only be extracted via drilling through areas where a viable, porous and permeable fracture network exists.
Boreholes are drilled using drill bits coated with diamond, one of the few materials which can withstand the pressures of cutting into hard rock formations. It’s no secret that for any geothermal project the largest percent of the capital is absorbed by drilling. But did you know that the techniques and equipment used for petroleum exploration and extraction are largely the same as for the geothermal resource? The main difference between both methods occurs in the end-product and the carbon footprint for energy production.
With so many abandoned wells creaking in reminiscence of their oily days, investigations have been underway to determine if they can be used for geothermal energy extraction. Drilling geothermal wells are costly and time-consuming. According to Bu et al. (2012)1, using an existing well reduces investment costs by 50%. These wells also provide the opportunity to extend the length of the drilled well to access more favorable thermal conditions at further distances, and liabilities related to plug and abandonment are eliminated. Converting petroleum wells to geothermal wells is, therefore, an economical solution for heat extraction. In most cases, these wells are linked to lower temperature resources and applications will be primarily for direct heating purposes – such as conversion to heat exchangers. Work has already been done to model heat transfer in abandoned petroleum wells and to estimate heat production potential to evaluate the optimal operating conditions for geothermal wells (Sui 2018)2.
As more dedicated efforts are being made in the drive towards a cleaner and energy sustainable future, it will be interesting to see how effectively abandoned oil wells can be converted for geothermal heating.
A great example of Co-Production in action – click here: North Dakota Oil, DOE and Universities work together in the name of Geothermal!
Interested in learning more? Check out Southern Methodist University. SMU has a dedicated Geothermal Laboratory focused on the potential of Co-Production.
For more on this topic and others, keep reading our Blog featuring #GeothermalFactsandStats and follow us on all our social media platforms.
1Bu X., Ma W., Li H. (2012) Geothermal Energy production utilizing abandoned oil and gas wells. Renew Energy 41: 80 – 85
2Sui D., Wiktorski. E., Roksland M., Basmoen T.A. (2018) Review on Investigations on geothermal energy extraction from abandoned petroleum wells. Production Engineering Journal of Petroleum Exploration and Production Technology https://doi.org/10.1007/s13202-018-0535-3
Author: Elizabeth Bullock
#geothermal #geothermalenergy #lovegeothermal #renewableenergy #coproduction #oilandgas #O&G #reducedrillingcosts #heatpower #abandonedwells