Patent ID: 8499841

Claim:
A method of treating a down hole well zone comprising: providing a zone treatment tool having at least a first and second zone treatment sleeves separated by seals; providing each of said first and second zone treatment sleeves with a threaded inner wall and a piston plug threaded to said threaded inner wall; providing each of said first and second zone treatment sleeve piston plugs on said number of zone treatment sleeves with a plurality of detents on one of said upper and lower surfaces, and providing the respective other of said upper and lower surfaces with a plurality of projecting tabs, wherein each of said first and second piston plugs define a ball valve seat and bore therethrough, whereby said first piston pug selectively provides fluid communication between an upper zone above said first piston plug and an intermediate zone below said first piston plug and above said second piston plug, and whereby said second piston plug selectively provides fluid communication between the intermediate zone above said second piston plug and a lower zone below said second piston plug; connecting said zone treatment tool to an amount of tubing and lowering the tool into a down hole well to an area to be treated; dropping a ball sized to fit in at least one of the ball valve seats to seal at least one zone from another zone; lowering a retrieval tool into the down hole well, said retrieval tool having one of a plurality of detents and a plurality of projecting tabs to mate with respective projecting tabs or detents on said first piston plug upper surface; rotating said retrieval tool to release said piston plug from the inner wall by unthreading the tool until the piston plug is free from said first zone treatment sleeve; dropping said first piston plug into registration with said second piston plug by mating one of said first piston plug plurality of detents and said first piston plugs with a respective mating one of said piston plug plurality of detents and said second piston plugs; lowering said retrieval tool into registration with said first piston plug; and rotating said first piston plug to unthread said second piston plug from said second first zone treatment sleeve.