US Patent 10156124 Balanced piston toe sleeve

A balanced piston toe sleeve allows a pressure test cycle to be carried out before opening the bore of the toe sleeve to the wellbore. The balanced piston toe sleeve includes a valve assembly in which a valve piston separates a valve cylinder into a balancing cylinder and an actuation cylinder. The actuation cylinder is coupled to the bore through a check valve which allows unidirectional flow into the actuation cylinder. The balancing cylinder is in fluid communication with the bore. After a pressure test cycle, the pressure in the balancing cylinder reduces, while the pressure in the actuation cylinder is retained by the check valve. The valve piston shifts into the open position, allowing fluid flow from the bore to the toe sleeve.