Casing Plug

Abstract

A dissolvable plug for plugging oil and gas well casings to perform treatment and other downhole operations is disclosed. The plug is attached to a setting tool and lowered downhole. The setting tool is fired to cause the plug to engage the casing and to release the setting tool. A ball is dropped to close the passage through the plug. Hydraulic pressure is applied on the ball from above and the plug expands outwards to create a seal between the plug and the casing. After operations above the plug are completed, the ball and the plug are dissolved by the surrounding fluids.

What is claimed is: 
     
         1 . A plug for sealing a casing having an inner surface, comprising:
 a first member having a sealing member;   a slidable second member connected to the first member; and   a third member slidable over the first member;   the first, second and third members being dissolvable after a certain amount of time.   
     
     
         2 . A plug for sealing a casing having an inner surface, comprising:
 a first member having a sealing member; and   a slidable second r connected to the first member;   the first, second and third members being dissolvable after a certain amount of time.