TL;DR: we run data centers on-site at oil wells and take natural gas that would otherwise be flared (it can't be economically transported as natural gas in a pipeline or turned into electricity and transported) and combust it completely. Methane is a significantly more potent greenhouse gas than CO2, so it ends up being a net reduction in emissions vs what's currently happening.
https://www.crusoeenergy.com/digital-flare-mitigation has some more information.