Patent ID: 9506323
Filing Date: 2016-11-29
CPC Classification: E21B

Claim Text:
1. A downhole system having a chemical injection valve assembly configured to inject at least one chemical from a chemical injection line into a downhole tubing, the chemical injection valve assembly comprising: a passive access control mechanism configured to reveal a first port to the tubing in a first condition and block the first port in a second condition, the passive access control mechanism including a housing, a movable piston movably supported within the housing, and a spring supported within the housing and biasing the piston to block the first port in the second condition, wherein in the first condition the piston is exposed to a first pressure source on a first side of the piston and to a second pressure source on a second side of the piston, the first pressure source from within the tubing and the second pressure source from outside of the chemical injection line and the tubing, an interior of the housing in communication with a first inlet exposed to the first pressure source, and a second inlet in the housing exposed to the second pressure source.