One trip packer plug debris milling and removal method

A combination tool is delivered to compacted debris above a packer whose plug is to be removed. The shoe or mill is on the lower end of an outer bushing and the grapple or overshot is held within the bushing but away from the shoe so that the shoe can advance into the debris as reverse circulation takes the cuttings up through a mandrel to a debris removal tool. When the shoe lands on the packer the surface personnel can see it on the weight indicator. Weight is then set down to overcome a resisting force of a breakable member such as a shear pin or a spring or both so that the grapple advances to engage the packer plug. Advancing the mandrel relative to the bushing with the shoe at its lower end also releases a torque lug that previously allowed tandem rotation of the mandrel with the bushing.