ou must not listen to yourself. Once again, bakken shale' has no natural drive because permeability is in the micro- to nano-Darcy region and there can be no upward pressure on the fracted regions (other than from the immediate surrounding structure around the fracture)
We also know there is no natural drive from historical evidence. The oil would have seeped upward and evaporated/oxidized at the surface, as there is no cap rock above the shale, no anticline.
non, non est non. The drive has zip all to do with the permeability. Most of the shale gas reservoirs are overpressured, meaning that the gas pressure is much higher than the surrounding water pore volume pressure. By merely opening up a pathway to the borehole you create a large pressure sink and that is your drive mechanism. Add into that some downhole pumps which would increase the sandface differential pressure and you have production that is relatively predictable based on type curve analysis.
The shale itself is the "caprock". With nano-darcy permeability your can't naturally flow gas through the pore space interstices unless the internal pressure of the gas exceeds the frac gradient of the shale and surrounding rock. That can happen but you end up with a crack seal phenomena where pressure is increased to failure strength, a natural fracture occurs, some gas migrates away and pressure drops immediately such that the fracture seals itself.
OH and you are completely wrong on demand tanking the gas price. It was indeed too much gas coming on stream. You can see this because the gas prices were coming down well before the economy went pear shaped. The economic mallaise of course helped to accentuate the price decrease but there was definitely too much supply on the market. IF you go back to industry observer posts from before the collapse you can find all sorts of discussion on the topic.