Abstract
Wellheads are complex equipment that connect the wellbore to the surface and execute multiple functions, such as pressure containment, load support, annulus access and wellbore sealing. These functions are essential for the safe and efficient operation of the well. The design of wellheads is based on the well conditions and operational requirements, such as pressure, temperature, flow rate, corrosivity, and service life. The wellhead design must comply with the relevant standards and specifications to ensure the quality and reliability of the device. The wellhead design must also use appropriate materials, dimensions and configurations to handle the expected loads and stresses that arise from the weight of the tubing, casing and equipment, as well as from the internal and external pressures and temperatures.
The effective management of fluid flow in or out of the wellbore is dependent upon the function of the wellhead valves, which serves as a crucial regulatory mechanism. They must be inspected and maintained regularly to ensure their functionality and integrity. Valve failures can have various causes, such as corrosion, erosion, debris, thermal expansion or improper operation. A prevalent issue affecting valves is referred to as the "stuck valve," which happens when the valve stem or disk cannot move freely due to friction or obstruction. The occurrence of a stuck valve has the potential to cause significant operational delays, safety hazards, and environmental risks.
When addressing a malfunctioning valve, a variety of tools and procedures may be implemented depending on the type and location of the valve. Some of the tools that can be used are valve wrenches, valve actuators, valve reamers and valve pullers. These tools can help to loosen or remove the stuck valve by applying force or torque to the valve stem or disk. Some of the procedures that can be used are applying lubricants or penetrants, tapping or heating the valve body, reaming the valve guide or removing the valve from the wellhead.
This paper aims to discusses the design, function and maintenance of wellheads and wellhead valves. It explains how wellheads and valves are essential and describes the common problems that can affect wellheads and valves, such as stuck valve, and how to fix them using different tools and procedures. It concludes by emphasizing the importance of wellhead and valve performance and safety for the well and the environment.
