I drop the BC Pump over the oil geyser and plop a Tesseract on top of it - Receive Power/Send Fluids. It immediately begins working, but it is slow and takes 2 hour to clear out the large oil wells. My tesseract is drawing power from my max-sized Big Reactor Turbine at around 28K RF/t and the Oil goes into a Railcraft Tank via the same channel on the Tess. There's no bottleneck on my power (this setup runs my Ender Quarry at lightning speeds), the bottleneck is absolutely on the BC Pump. It has always pumped at this slow speed no matter what modpack I play, I've been doing this method for a few years now.
I often fly down into the well to wait for it to finish, so I can return back to base. I watch it work. It removes 1-3 blocks of oil per second, roughly. So each level of the oil will take 10 minutes or so to finish, and the big wells can have 12+ levels to drain down.
I'd sure love to solve this problem, but I just don't think your answer is correct, unfortunately. Someone show me I'm the one who is wrong!
I don't know if this would solve your problem with the slowness, but the BC Pump has the ability to suck up fluids from whatever touches it's pipe. This is a recently added feature, I discovered this when I was clearing out a lava lake in a map I was playing. Why not move the BC pump down to where it can directly touch the main oil deposit, and see if it sucks up the oil column from above as it comes flowing down?
Instead of having to wait for the pump to descend to the next layer you only have to wait for the oil to flow down, unless the BC Pump starts at the topmost liquid tile it can find and works it's way down from that.
The BC pump can take quite a bit of time to suck out a large oil deposit, it's very cheap resource-wise though.