Definition
Drop-In Check Valve — A drop-in check valve is a check valve dropped or pumped down the drill string to land in a preset sub, where it establishes one-way, downward-only flow so the string can be shut in against upward flow without breaking any connections.
Also known as: drop-in check valve, dart-type check valve, pump-down check valve
What a drop-in check valve does
A drop-in check valve is deployed by dropping its dart-like cartridge into the open drill string and pumping it down to a landing sub made up in the string beforehand. Once seated, it acts as a back-pressure check valve: fluid can be pumped down through it, but upward flow is blocked. This lets the crew establish a string barrier during a kick without having to stab a surface valve or break a connection.
Because the valve is pumped into place, it can be set even when the well is flowing, and it is retrievable in some designs. It provides a downhole check to complement the surface full-opening safety valve and inside BOP.
When it is used
- As a contingency barrier when a surface valve cannot readily be stabbed.
- During circulating operations to hold back-pressure in the string.
- In combination with a landing sub pre-installed at a chosen depth in the string.
Why it matters for rentals
The landing sub and drop-in cartridge must be a matched, pressure-rated set with current certification. Rental units should suit your drill-string bore and working pressure. Explore our pressure control equipment and well control application, or contact us.