Dump valve arrangement for fracturing tool set

Abstract

A dump valve arrangement for a fracking tool coupled to a length of coil tubing includes an axially displaceable inner mandrel which cooperates with a valve arrangement to allow for releasing fracturing fluid through the central bore of a fracturing tool to an outlet port positioned at the bottom of the tool string. Displacement of the inner mandrel is effected as a result of the normal sequence of operation of the fracturing tool set. The valve arrangement is in a closed position during both the insertion and positioning of the tool string. Fluid pressure from the injection of fracturing fluid into the formation maintains the inner mandrel and valve arrangement in the closed position. When fluid injection ceases, withdrawal of the coil tubing unit causes axial displacement of the inner mandrel thereby opening the valve arrangement, allowing fluid to drain through the center of the tool string and out into the well bore through the outlet port.

Dependencies are inferred from the claim text.