Abstract: An apparatus for selectively fracing a well includes a tubular body having an exterior surface, and an interior surface that defines an interior bore. An annular flow area that has at least one fluid flow port extends radially through the tubular body to permit fluids from the interior bore to pass through the at least one fluid flow port into a surrounding earth formation. An external sealing sleeve selectively covers the annular flow area. There is a pressure actuated sleeve shifting mechanism, where increasing pressure tending to cause axial movement of the external sealing sleeve. The axial movement is resisted until a pre-selected pressure threshold is reached to permit movement of the external sealing sleeve to open the at least one fluid flow port.

Abstract: An enclosed circulation tool for a well including a tubular body having a top end, a bottom end and an interior cavity. A progressive cavity pump positioned at the bottom end of the body, the pump having a rotor mounted within a stator. The rotor has an upper end and a lower end, with the upper end extending into the interior cavity. A drive is coupled to and adapted to rotate the rotor in order to draw sand into the interior cavity. A first fluid passage is provided along which fluids from pumped from surface pass to fluidize solids within the interior cavity. A second fluid passage is provided along which fluidized solids from within the interior cavity pass to surface.