In the oil and gas industry, materials range from different pipe materials to various accessories that make them function. Some of those vital accessories are wellheads.
A wellhead is a structure located at the top of an oil/gas well. Its primary purpose is to provide the structural interface for any of the drilling and production instruments. Some of its components include:
- Casing heads, spools, and hangers
- Tubing heads, hangers, and head adapters
- Choke manifold
- Mudline suspension systems
Why Are Wellheads Essential?
When the casing string goes into a wellbore, the wellhead provides pressure seals that manage the oil and gas pressure and flow. They are essential in performing a wide array of functions like:
- Providing suspension for tubing, which is a removable pipe installed to provide a means through where well fluids pass.
- Avoids the risk of an uncontrolled release of crude oil or natural gas, known as a blowout, and is the means of attaching a blowout preventer during drilling.
- Allows access to the annuli between the different casing and tubing strings.
- Permits access to the well and the ability to connect a well pump.
Wellhead vs. Christmas Tree
Many people believe that a wellhead and a Christmas tree are the same things, but they are different pieces. The wellhead provides the means for attaching a Christmas tree for production operations.
The Christmas tree, unlike the wellhead, can’t function on its own. The primary purpose of this tree is to control the flow into or out of the well. They are typically composed of the following five valves:
- The Kill Wing valve
- The Swab valve
- The production wing valve
- The upper master valve
- The lower master valve