Drill pipe float valves are commonly used on drilling rigs to provide additional blowout protection at the bottom of a drill string. When connecting drill pipe joints, they also keep cuttings out of drill pipes to avoid bit plugging and flowback. In this article, we’ll provide an overview of the different types of float valves, along with an overview on how to remove them.
Float Valve Types
There are a variety of float valves available–it’s important to choose the best fit for each drilling project. Two basic types are plunger valves (Model Fs) and flapper valves (Model Gs). Specific varieties include:
- Model F – Used to provide constant fluid control during drilling, it also allows for positive instantaneous shut off. It is the most economical choice among floating valves.
- Model FA – Used for monitoring gas pressure on the drill bit head.
- Model FC – Features a key assembly and slotted valve stem. This is used to keep the plunger open for a drill run. The plunger is released automatically once circulation starts.
- Model G – Used to offer an unobstructed bore through the float valve. The flapper serves to keep shavings from entering the drill once circulation ceases. Furthermore, once the first joint is added, the float valve will open, preventing the pulling of wet joints.
- Model GA – Similar to the Model G with the addition of a tungsten-carbide insert, it also has a small orifice for differential pressure monitoring.
- Model GC – Features a key assembly and slotted valve stem, this model is used to keep the flapper partially open for a drill run. This float valve has the ability to run in an automatic-fill or closed position.
- Model GCA – Combines all the features of other Model G valves.
Valve Pullers
Valve pullers are essential to the proper removal of float valves. The process varies depending on the type of float valve used, but we’ve provided the basics below:
- Model F Valves – The user, while pressing against the head of the valve plunger, will need to squeeze the forks together. The valve can be pulled once the forks are engaged. Afterwards, the user can slide the separator from the valve and squeeze the forks together to remove the puller. Please note that with Model FC valves, use caution to ensure when handling the catch so that it doesn’t come in contact with the releasing key.
- Valve pullers can also be used to remove tight or stuck float valves from the collar of a drill or sub. In the case of F valves, you can engage the special catch into the bottom of the float valve, rotate it by 90 degrees, and then slide the bumper into the stop.
- Model G Valves – The use of these pullers is similar to those for F valves. However, the model G puller has the additional function of removing and installing the seal retaining ring.
Valve pullers for Model Gs can also be used to help install and remove the seal retaining ring when you need to switch the valve seal.