Tubing String Testing (TST) Valve

The tubing string testing (TST) valve is a full-opening valve used to pressure-test the workstring while running in the hole. The valve is operated after it is stung into a permanent packer or after a retrievable packer is set. The TST valve requires a differential pressure between the annulus and the tubing to shear. The TST valve can also be used for pipe flexing if it is run below an annulus pressure-responsive circulating valve. The TST valve consists of: flapper valve and spring shear pin section locking dogs Features and Benefits Flapper valve requires only 4 psi to open. Testing string can be pressure-tested as many times as required as it is run in the hole. Valve shear rating can be pre-determined at 500 psi increments. Valve can also be used for pipe flexing.