Abstract: A chemical injection valve can include a valve stem, flow between sections of a flow passage being prevented and permitted in respective closed and open positions of the valve stem, a resilient primary seal that prevents flow through an annular gap surrounding the valve stem in the closed position, and a bypass passage in communication with the annular gap and a flow passage section, and in communication with another flow passage section in the open position. A chemical injection system can include a chemical treatment pumped through a chemical injection valve and into an interior of a tubular string, and the chemical injection valve including a valve stem and a bypass passage extending between a flow passage section and an annulus surrounding the valve stem, the annulus being positioned longitudinally between a resilient primary seal and a metal secondary seal.

Abstract: A chemical injection valve can include a valve stem reciprocably disposed relative to a primary seal, and a variable flow restrictor upstream of the primary seal relative to a direction of flow through the chemical injection valve. The variable flow restrictor restricts the flow when the valve stem is disengaged from the primary seal. A chemical injection system can include a chemical treatment pumped through a chemical injection valve and into an interior of a tubular string in a well, the chemical injection valve including a valve stem, a primary seal sealingly engaged with the valve stem in a closed position and disengaged from the valve stem in an open position, and a flow restrictor that restricts the flow of the chemical treatment downstream from the primary seal in the open position.

Abstract: A chemical injection valve can include a valve stem, flow between sections of a flow passage being prevented and permitted in respective closed and open positions of the valve stem, a resilient primary seal that prevents flow through an annular gap surrounding the valve stem in the closed position, and a bypass passage in communication with the annular gap and a flow passage section, and in communication with another flow passage section in the open position. A chemical injection system can include a chemical treatment pumped through a chemical injection valve and into an interior of a tubular string, and the chemical injection valve including a valve stem and a bypass passage extending between a flow passage section and an annulus surrounding the valve stem, the annulus being positioned longitudinally between a resilient primary seal and a metal secondary seal.

Abstract: A chemical injection valve can include a valve stem reciprocably disposed relative to a primary seal, and a variable flow restrictor upstream of the primary seal relative to a direction of flow through the chemical injection valve. The variable flow restrictor restricts the flow when the valve stem is disengaged from the primary seal. A chemical injection system can include a chemical treatment pumped through a chemical injection valve and into an interior of a tubular string in a well, the chemical injection valve including a valve stem, a primary seal sealingly engaged with the valve stem in a closed position and disengaged from the valve stem in an open position, and a flow restrictor that restricts the flow of the chemical treatment downstream from the primary seal in the open position.

Abstract: A valve for performing gas lift operations is provided that incorporates two edge-welded bellows and a ball-orifice closing mechanism. The gas lift valve incorporates features enabling enhanced compression of one of the bellows, beyond an initial closure point of the valve. For example, a stem with the sealing ball is divided into two components, wherein one of the stem components is configured to continue moving in relation to the other stem component with the ball, which is fixed in position when the ball seals the orifice and initially closes the valve. This continued movement allows one of the bellows to be fully compressed in the ultimately closed valve position, thereby protecting the bellows from high pressures and potential failure that could occur to bellows in a partially compressed state.