Sponge pressure equalization system

摘要

A system for obtaining a core sample from a wellbore includes a housing having a core opening at a first end of the housing and an end wall at a second end of the housing. A balancing piston is positioned within the housing to define a sample chamber between the balancing piston and the core opening. An equalization chamber is defined between the balancing piston and the end wall. A core piston is sealingly positioned in the core opening.