Differential Shifting Tool and Method of Shifting

A shifting tool for use in a hydrocarbon production well, the shifting tool comprising:

• a housing assembly having an annular sidewall, at least one pad port disposed through said sidewall, and at least one collet port disposed through said sidewall;
• at least one friction pad alignable with said at least one pad port, said at least one friction pad being radially movable through said at least one pad port between a first pad position and a second pad position, wherein in said second pad position said at least one friction pad extends through said at least one pad port;
• a mandrel having a flowpath extending between an upper end and a lower end, said mandrel being positioned at least partially within said housing assembly and having piston section and a collet engaging section, wherein said mandrel is moveable between a first mandrel position and a second mandrel position, wherein in said second mandrel position said piston section supports said at least one friction pad in said second pad position;
• a collet having an upper end, a lower end, a plurality of keys moveable between a first key position and a second key position, each of said keys having an inner portion and an outer portion, wherein in said second key position said outer portion extends through said at least one collet port;
• a collet spring positioned in the annular space between said mandrel and said housing assembly, said collet spring being longitudinally compressible by upwell movement of said collet;
• a spring stop fastened to said mandrel;
• a return spring having an upper and lower end, wherein said return spring is compressible by downwell movement of said spring stop;
• wherein said collet engagement section comprises an first enlarged portion positioned upwell of a second enlarged portion.