What is wellhead?
Wellhead consists of components of an oil well which are located above the surface. Wellhead acts as an interface between the casing strings in oil wellbore and surface facilities. Well head provides suspending point for the casing strings running through the wellbore and also acts to contain the pressure inside the casing strings.
- Wellheads are also responsible for containing the pressure within each of the casing strings. During oil well drilling, casing is installed and cemented to the wellbore for containing the pressure and wellbore wall in place. Casing also serves to avoid mixing of fluids from different formations through which the wellbore runs.
- A well head provides means for suspension of casing strings running down the wellbore.
- A Blow Out Preventer (BOP) acts to cope up with erratic fluctuations of pressure and flow from reservoir. Wellhead serves as attachment point for the Blowout Preventers.
- Well head provides means for attaching a christmas tree for production operations. Christmas tree is equipped with set of isolation and choke valves and serves for pressure control.
- Tubings are passed through the casing from surface to the oil reservoir to facilitate the transfer of fluids to the surface. The tubings responsible for oil production are called production tubings. A well head also provides a point for suspension of tubings.
- Wellhead can be used for pressure monitoring for casings and annuli between different casing and tubing strings.
- Sometimes multiple casings are used in the same wellbore. These casings contain different well fluids. A wellhead serves to keep these casings separated from each other to avoid mixing of fluids.
- Wellheads also provide access for pumping from annuli between the different casing/tubing strings.
- Well head provides reliable access to well with possibility to attach a well pump.