ports 66 whose function will be explained more fully hereafter a snap ring 68 is normally disposed in an internal annular groove 70 between sleeve 58 and mandrel 26 reference is now made to fig1 5 for a detailed description of the method of the present invention employing well tool 10 in fig1 the operating tool string shown generally as 72 is shown being lowered into a well bore 74 while well bore 74 is shown as being open hole it is to be understood that the method and apparatus of the present invention find application in cased hole as well accordingly the term well bore as used herein is intended to mean either open or cased hole a perforated shoe or anchor 76 is connected at the lower part of operating tool string 72 supported above shoe 76 in tool string 72 is packer 78 a by pass valve 80 being supported in tool string 72 above packer 78 a valve assembly 82 supported above packer 78 and by pass valve 80 serves to selectively open and close a flow passage for circulation downwardly through string 72 to shoe 76 and upwardly from shoe 76 through string 72 well tool 10 which actually forms.