They didn't just start importing it while having their own. There is huge complex gas transportation system biult in 70s - 80s to supply both europe and ukraine. (btw ukrainian part of that system has been given to chevron virtually for free). Gas in Norther Russia and in Siberia doesnt take fraking to extract. While in Ukraine it's shale gas. And i hope you know what fracking dioes to soil and all local ecology but tha's another issue.

Looking at UA army tactics it seems that chevron enforces Kiev not only to win in Donbass but also to depopulate the area as much as possible (where they seem to treat their own soldiers not much better then the enemy and local civilians)