ASSEMBLY FOR TOE-TO-HEEL GRAVEL PACKING AND REVERSE CIRCULATING EXCESS SLURRY

摘要

A treatment assembly treats zones of a horizontal borehole. For example, the assembly can gravel pack a zone by delivering slurry down a workstring. The slurry exits the workstring's outlet and pass to the borehole annulus of the zone through a flow port in the assembly. The gravel in the slurry can pack the borehole in an alpha-beta wave from toe to heel, and the fluid returns from the borehole flow through a screen back into the assembly. After gravel packing, operators remove excess slurry from the workstring by reverse circulating down the assembly to carry the excess slurry uphole through the workstring. Closures on the assembly prevent the reverse circulation from communicating through the screens to the borehole annulus. Additionally, flow valves can be used on the flow ports to selectively open and close them.