After reseting a game with a few chronospheres, I eventually got to researching "Pumpjack" in the Workshop. But my oil production went from +.15 to -.25 when I did that. Was this a bug where my oil refine rate was kept from before the reset until i researched this? Or is this a bug where the "Pumpjack" upgrade just isn't working? It definitely seems like a bug tho.
Update: Actually, it seems that when I researched "Pumpjack", my oil well (i only had one built) was disabled. Still seems like a bug for that to happen.
Best Answer
What you ran into is a result of the new "Power" mechanic put in a patch or two ago.
Basic oil wells run on their own and do not consume power. Once you research Pumpjack to upgrade them, Oil Wells also start consuming power at 1 watt each, and can be shut on or off like any other building that needs power. By default, they start as off. That's what you ran into.
Just turn them on again and your upgrade should be clear.
I believe it's already been requested that the text on the upgrade clarify what's going on; the game has a couple new mechanics that aren't obvious off the bat.
In the current version of the game (Jan '19) this behavior has been modified, and your Oil Wells will automatically be turned on when the upgrade goes through.