Banter and General Comments .. BRK, page-187

Hi mate.

Initially in an unfracked well, the hydrocarbons do generally "geyser" out of the system to an extent as the formation pressure, the compression forces from the weight of rock, and the actual pressure exerted by the fluids within the formation is greater than the pressure of the open well bore once perforated. So that pressure forces the fluids out of the formation through the perforations in the production casing and up the hole.

The formation pressure drops as the reservoir depletes to the extent the pressure differential between the well and the formation decreases and that is when pumping may be introduced to suck the fluids out by creating another differential by decreasing the well bore pressure.

Fracking changes the physical properties of the reservoir to facilitate the pathways for the migration of hydrocarbons in a tight zone. The tight zone actually may be highly pressured, but won't flow oil and gas into a well in a meaningful way because of the lack of permeability.

The flowback fairly unique to fracking stimulation, as water is used to alter the physical property of the reservoir prior to first production rather than increasing the pressure and push oil up into a well bore as they do in secondary recovery water drive towards the end of the field life.

Cheers

Dan