The M-SAS Valve is a hydraulically actuated check valve. It offers enhanced protection against the release of a large volume of high pressure lift gas if the surface lines are damaged (e.g. by a dropped object in the wellbay).

 

The check valve design is similar to that employed in our gas lift valves. Consequently, it delivers much higher integrity and reliability than traditional gas lift line check valves.

 

It is designed to be installed inside VR profile within  the wellhead. The modular design of the M-SAS is such that the actuator can detatch from on severe impact. Consequently the check valve will always remain undamaged and  intact in the VR profile.

 

The M –SAS  valve is actuated (held open / fail safe closed) using the xmas tree ESD system. Consequently it is not be prone to wear and tear due to chattering as a result of fluctuating gas delivery rates and pressures. This means that the valve seal faces will be in excellent condition, whenever they are required to be so.

A further advantage of having an actuated check valve on the annulus line, is that the annulus can be readily bled down, without the requirement for a temporary rig up. This can save a lot of time during inflow testing operations.

 

In Norway and Canada the DH ASV’s have become a common feature in gas lift completion designs (to reduce the annulus volume that might be released in the event of an incident). These have however proved to be unreliable. A large number of wells have therefore had to be closed in pending a workover to replace them. The M-SAS valve has now been approved by the authorities in these parts of the world as a suitable alternative to DH ASV’s. As a result costly workovers are being avoided by simply retrofitting M SAS valves. Some OPCO’s are however installing both DH ASV’s and M-SAS valves as they believe this delivers the ALARP risk profile.

 

The M SAS valve can also be used in non gas lift applications (ideally in conjunction with our VR plug pressure / temperature sensor)  to facilitate controlled pressure bleed off from A,B or C annulus. 

 

A variant of the valve can also be used for chemical injection applications; M–SAS CIV.

 

The H SAS is a non modular (i.e. non detatchable actuator) version of the actuated SAS valve. It is used in cases where the wellhead flange is long enough to accommodate both the VR check valve and actuator in one piece.