The subsea wellhead system (Fig. 1) is a pressure-containing vessel that provides a means to hang off and seal off casing used in drilling the well. The wellhead also provides a profile to latch the subsea blowout preventer (BOP) stack and drilling riser back to the floating drilling rig.
The primary purpose of a wellhead is to provide the suspension point and pressure seals for the casing strings that run from the bottom of the hole sections to the surface pressure control equipment. While drilling the oil well, surface pressure control is provided by a blowout preventer (BOP).
what is a subsea Christmas tree? Subsea tree (wet trees) is a system of valves, flow paths, piping, and connectors installed on a subsea wellhead to contain and control the flow of fluid from a reservoir or from the surface by injection.
Subsequently, question is, what is the difference between wellhead and Christmas tree?
Wellheads and Christmas Tree are not the same. A wellhead consists of heads, hangers, spools and a series of seals. Christmas Tree consists of chokes, valves and spools. The main purpose of christmas tree is to control the flow of well fluids or gas during production.
What is a subsea manifold?
Subsea manifold is a flow-routing subsea hardware (subsea flow router) that connects between subsea trees and flowlines. It is used to optimize the subsea layout arrangement and reduce the quantity of risers connected to the platform.
How big is a wellhead?
Regardless of its purpose, a well is defined as an artificial hole in the land surface created to access a liquid. It normally has a small diameter, typically less than 3 meters (10 feet), and usually measured in centimeters (inches). Wells may be constructed to seek water, oil, or natural gas.
How does a well head work?
The wellhead is the component at the surface of a well that provides the structural and pressure-containing interface for the drilling and production equipment. The Christmas tree and the wellhead work together to bring oil and gas to the surface. Tree complexity has increased over the last few decades.
What is a well header?
n. [ Production Facilities] In a gathering system, a pipe arrangement that connects flowlines from several wellheads into a single gathering line. A header has production and testing valves to control the flow of each well, thus directing the produced fluids to production or testing vessels.
What is wellhead maintenance?
Expro’s wellhead maintenance services form a key part of Expro’s well integrity capability – from new HPHT developments, through to the mature brownfield site. This includes the routine inspection, repair and maintenance of surface wellheads, as well as the provision of pressure testing services.
How do you get a well head?
Establish which wall of the basement the pipe from the well comes in on, and measure the distance off the corners of the foundation. Go outside the house and use that location as the starting point to find the well-head.
What is a wellhead platform?
Wellhead platform generally is a type of oil platform that houses personnel and machineries to extract oil and natural gas through wells in the ocean bed. A wellhead platform (WHP) may include an integrated deck, utility systems, wellhead systems, helideck and drilling facilities.
How does a wellhead choke valve work?
A wellhead choke controls the surface pressure and production rate from a well. Chokes usually are selected so that fluctuations in the line pressure downstream of the choke have no effect on the production rate. Under critical flow conditions, the flow rate is a function of the upstream or tubing pressure only.
How does wellhead compression work?
Wellhead Compression. Wellhead compression (WHC) is the solution by which a compressor acts locally over one or a number of wells. As a result, the back pressure for a number of selected wells can be reduced. WHC extends the life of oil and gas wells and boosts their production output.
What is a wellhead choke used for?
Wellhead chokes are used to limit production rates for regulations, protect surface equipment from slugging, avoid sand problems due to high drawdown, and control flow rate to avoid water or gas coning. Two types of wellhead chokes are used. They are (1) positive (fixed) chokes and (2) adjustable chokes.
What is Sssv?
subsurface safety valve (SSSV) Two types of subsurface safety valve are available: surface-controlled and subsurface controlled. In each case, the safety-valve system is designed to be fail-safe, so that the wellbore is isolated in the event of any system failure or damage to the surface production-control facilities.
What is a Xmas tree in oil and gas?
In petroleum and natural gas extraction, a Christmas tree, or “tree”, is an assembly of valves, spools, and fittings used to regulate the flow of pipes in an oil well, gas well, water injection well, water disposal well, gas injection well, condensate well and other types of wells.
What is kill wing valve?
Kill wing valve (KWV). It is a manually operated valve used for the injection of fluids such as corrosion inhibitors or methanol to prevent hydrate formation. In the North Sea, it is called the non-active side arm (NASA). Production wing valve.
What is a production tree?
1. n. [ Production] A Christmas tree that is installed once fracturing has been completed and the frac tree has been removed. Production trees tend to have smaller bores and lower pressure ratings than those of frac trees, which makes them more economical to use during the less-demanding production phase.
What is Scssv?
A downhole safety valve that is operated from surface facilities through a control line strapped to the external surface of the production tubing.