Geothermal
Doublets and closed loops
minutes reading time
Rod Gibbons
The efficient production of energy is a core principle in petroleum engineering, and the requirement for high integrity well construction makes the geothermal industry a natural fit for Ballycatter Engineering.
We have used our petroleum background to plan and engineer geothermal projects utilizing existing gas wells for conversion to geothermal, either through a two-well doublet pair or closed loop single well.
Other projects: ESP Design
Heat from the earth
Common industrial geothermal projects involve injecting high volumes of water into an injection well (with a 7" completion, for example) and allowing the water to flow through the permeable reservoir rock to the production well where the water is lifted using and electric submersible pump.
It is important to ensure the fluid flow dynamics do not erode or corrode the well components, that injection and production rates are balanced to allow proper stremtube flow to develop, maximizing heat transfer, and the thermal shock of injecting cold water does not setup stresses in the geologic strata that could cause a failure.
For smaller scale geothermal projects the use of a single wellbore and circulating down the annulus, picking up heat from the ground and then returning up the tubing, with a thermal break between the two is an efficient way to provide relatively low volumes of heat, which may be used for a medium sized building or a small neighbourhood for example.
Re-use of existing assets
Ballycatter Engineering has developed projects for both doublet and closed well applications in cooperation with industry partners, Delft University Geothermal Faculty, and the Dutch government. We also have a network of experienced off-takers who can arrange energy contracts and subsidy preparation.
We see geothermal (especially closed loop) as a green, renewable energy that holds promise as a preferred alternative over blanket abandonment of existing gas and oil wells.
"ensure... outcomes fit for the geothermal industry"
A history of development
Geothermal projects have there own challenges which need close attention during planning and execution. An data-driven, open minded approach has proven to give better project results and acceptance from regulators on geothermal well construction designs.
As a relatively "new" industry (not really), it is important that geothermal projects apply lessons learned from the oil and gas industry, but continues it's independent thought process to ensure project outcomes that are a fit for the geothermal industry.
Homepage >
