About Wellhead Equipment, you have to know these basic knowledge

General inforamtion:

The wellhead device is a production equipment used for suspension, support, control and adjustment of oil christmas tree, tubing head, casing head and related accessories. As an important equipment for oil and gas production, its performance is related to the safety and efficiency of oil and gas well production.


All about Casing head:
The casing head is an important connector between the casing and the wellhead. The lower end is connected to the surface casing through the thread, and the upper end is connected to the wellhead device or blowout preventer through a flange or a clamp.

The general casing head

The characteristics of the casing head.

The casing connection can be connected either by thread or slip, which is quick and convenient.

The casing is made of rigid and rubber compound seal structure, and metal seal can be used to increase the sealing performance of the product.

The design is equipped with the anti-wear sleeve and the test pressure removal tool to facilitate the removal of the wear sleeve and the test pressure on the casing head;

The upper flange is designed with test pressure and secondary grease fitting;

Casing head flank valve configuration, according to user demand design;

The action of the casing head.

The casing head is mounted on the upper end of the surface casing string, which is used to hang the wellhead device parts of the casing outside the surface casing and the annular space of the sealing casing. The main functions are as follows.

1. Hoisting part or all weight of each layer of casing other than surface casing through the hanger;
2. Connect the blowout preventer and other wellhead devices;
3. Pressure seal is formed between inner outer casing string;
4. Provide outlets for the release of pressure that may accumulate between the two sets of pipes;
5. In case of emergency, the fluid can be pumped into the well by the side hole of the casing head, such as the kill fluid or extinguishing agent;
6. Special operation: a. The quality of cementing well is not good enough to be filled with cement, b. The pressure balance can be injected from the side hole when the acid fracturing is done.

casing head structure

For good memory, the function and use of the casing head are summarized into four sentences:

Suspension of casing weight;

Support casing head above blowout preventer;

Provide a seal for each layer of casing;

Provide channels for special operations;