Abstract: An axial locking mechanism includes a lock and a rod. The lock includes a lock aperture and an axis passing through the lock aperture. The rod is receivable by the lock aperture along the axis. In a first rotational orientation about the axis, the rod is movable within the lock aperture along the axis and relative to the lock. In a second rotational orientation about the axis, the rod is fixed within the lock aperture along the axis and relative to the lock.

Abstract: The present invention is directed to a bottom-up method of fracturing a multi-zone subterranean formation intersected by a wellbore that enables one zone to be fractured while at the same time flowing previously placed fracture fluid from one or more other zones back to the surface. The method employs a bottom-hole assembly (“BHA”) that is attached to the bottom end of a tubing string. The BHA includes a hydra jetting sub, a centralizer, a packer and valve sub. The hydra jetting sub is used to perforate and initiate the fracture in the zones of interest. The zones are fractured by pumping fracturing fluid down the annulus formed between the tubing string and the wellbore. The previously placed fracture fluid flows back to the surface through the tubing string. It enters through the valve sub in the BHA.