This is part of the series of tech talk posts on how to get fossil fuels out of the ground that appear here most Sundays. In this post, I talk about several innovations in drilling, including down-hole motors. Among other things, down-hole motors made it possible to turn tighter corners with the drill bit, enabling horizontal wells.

The last post in this series dealt with directional drilling, where I had mentioned the need to go back in time to the period where the then Soviet Government was developing the Volga-Ural basin in the Soviet Union, back in the 1950's. And I quote from John Grace's "Russian Oil Supply."