Re: [TRNSYS-users] What is recommended single borehole spacing

["Jeff Thornton" <thornton@tess-inc.com>]

<I am working on a project to model a single borehole for harnessing
thermal energy from abandoned oil and gas  wells.  I would like to know
what the recommended borehole-to-borehole spacing should be for a single
borehole in the duct storage model.>

That's actually a really good question even though some people will think
it's a silly question as there is "no" bore-to-bore spacing with 1 bore. 
The key is that the spacing between bores is not really a parameter to the
model but we use it in the plug-in to help people set the storage volume -
the volume of soil containing the bores.  This volume is important as it's
the volume that is calculated with the short-term "local" solution while
the soil outside the storage volume is calculated with a longer-term
"global" solution.  I would set the storage volume based on the volume of
soil that you think will be affected by the heat transfer near the well:

Storage volume = Pi * Height * (0.525 * Spacing)^2

and then back-calculate the spacing to give you that volume.  I would also
suggest that you play with the spacing and see how your results change -
and let me know what you find!

Jeff


Jeff Thornton
President - TESS, LLC

22 North Carroll Street - Suite 370
Madison WI 53703 USA

Phone: 608-274-2577
Fax: 608-278-1475
E-mail: thornton@tess-inc.com
Web: www.tess-inc.com