US Patent 9574423 Safety valve with electrical actuator and tubing pressure balancing

A well tool for use with a subterranean well can include a flow passage extending longitudinally through the well tool, an internal chamber containing a dielectric fluid, and a flow path which alternates direction, and which provides pressure communication between the internal chamber and the flow passage. A method of controlling operation of a well tool can include actuating an actuator positioned in an internal chamber of the well tool, a dielectric fluid being disposed in the chamber, and the chamber being pressure balanced with a flow passage extending longitudinally through the well tool, and varying the actuating, based on measurements made by at least one sensor of the well tool.