Wellhead accessories:
After drilling and completing the well in order to control it and also in order to operate the well according to its anticipated location and needs, equipment will be installed on the well. Some of these devices are placed directly on the well itself and some of it is placed near the well and in connection with the first part.
These devices are designed according to the well used, how to complete it, pressure and the presence of acid gases. The set of equipment that is installed directly on the well itself is known as Y-Mas Tree, which also has different models (types of crown well models and each used in a set of the same name in the General Iranian Oil Company as standard It is available, it is mentioned.
Despite the differences in some parts of the crown of different wells, in many cases they are similar and only sometimes the type of device used is different while performing the same operation.
The equipment on the crown of the well is installed from the ground up in the following order:
Base Flange:
This head pipe is installed on the largest metal wall of the well that has come out of the ground and the rest of the equipment in the crown of the well is installed relying on this head pipe. In some cases, this hood is the starting point for measuring the depth of the well.
Side valves :
Checking the position of the well walls in terms of pressure and the type of fluid in them (if any) is done through these valves. Without exception, there is a valve on every wall and they are usually 2 inches in size. If we stand facing the well so that the curved part of the crown of the well (Swept Bend) is in front, the place of the mentioned valves is on our right side on the crown of the well.
Bottom Main Valve:
This valve is usually of the gate type (Gate Valve) or of the ball type (Ball Valve) and is usually 6 inches in size. The most important point of access to the well is this valve and in case of damage, it is necessary to repair or replace the drilling rig (if the well can not be temporarily blocked). Unlocking this valve is prohibited and is generally open unless permission has already been granted to operate it. (The reason for this is that the constant opening and closing of the valves usually exposes them to problems, and because this valve has a special position, it is avoided to work with it too much in this regard). It is located just above the side valves mentioned above.
Upper Main Valve:
The characteristics of this valve are similar to the lower main valve and its location is above the lower main valve. Wells are usually opened and closed by these lions.
Surface Safety Valve:
This valve is located on the upper main valve and its size is usually 6 inches. It has a special position that can be adjusted to open and close, and this adjustment is done to control the well pressure. Special pilots are installed on the normal type. One of these pilots is set to the minimum and the other to the maximum pressure depending on the position of the well.
The new models of this valve work with the Panel with the help of a device that is installed near the well.
Curved part:
In fact, from a three-way that is connected to the wellhead of the well on one side and is connected to the upper part of the well from the top, there are two third ways in the pipe path from the well and it is available in different sizes. × 6.6 (“6) inches, which has a low private appearance is called the above.
Source valve: Attaches to the top of the above three-way and is usually 3 or 4 inches in size. In fact, it is a channel for various tools to enter the well, and when an operation is to be performed inside the well (for example, preparing a diagram by measuring the internal pressure of the well), the operation is controlled by opening this valve, in addition, when measuring the well pressure Is meant to be used.
Upper part of the headgear:
Usually, a local well is installed on the top of the valve, which can be used for various connections (for different jobs that are inside the well.