Wellhead facilities
NoDoC cost model for cost estimation and cost simulation of wellhead facilities are designed such that is applicable for different types of oil & gas wells. It shows the assembly of sittings , valves and controls located at surface and connected to the flow lines,tubing and casing of the well to control the flow from the reservoir is called wellhead equipment . the wellhead equipment is used for sealing of oil and gas operation of the wells , hanging of the tubing and casing , controlling the performance and pressure of the well and adjusting the flow rate of oil and gas wells . this equipment is installed on the well after drilling operation and well in all type of wells like flowing wells , injection wells and pumping out wells . the wellhead equipment must be reliable in heavy conditions : highly polluted mediums with contents of S and up to 25% each , working pressure from 2000 psi up to 25000 psi and working temperature form 60 up to 120 .wellhead equipments are mainly made from plain carbon, low alloy and stainless steel depending on working pressure , working temperature , fluid constituents like S and pressure of them , location and kind of equipment . this equipment is mainly manufactured with forging or casting process and after suitable heat treating , attached to the other parts with thread , weld , slip , flange and other fittings .
Wellhead equipment shall be designed and manufactured according to “API spec 6A” material and performance requirements . according to this standard four product specification levels ( PSLs) are introduced for wellhead requirements . these four product specification levels (PSIs) are introduced for wellhead requirements . these four PSLs are PSL1 , PSL2, PSL3, and PSL4 depending on pressure and severity of service condition like pressure and concentration of S , ….) . wellhead equipments are divided into pressure containing and pressure controlling parts depending on working pressure .
Those parts whose failure to function as intended would result in a release of retained fluid to the atmosphere are called pressure containing parts. examples are bodies , bonnets, and stems . pressure- controlling parts are those ones intended to control or regulate the movement of pressurized fluids , such as valve bore sealing mechanisms , choke trim, and hangers.
For instance you can see below what NoDoC includes for Christmas tree:
On oil and natural gas wells, it is usually necessary to establish a series of valves to control the pressure and rate of flow of the gas and / or oil from the reservoir that said “ Christmas tree” it is attached to the uppermost connection of the tubing head . Christmas tree is mainly used for production wellhead to control pressure and for the oil (gas ) wellhead to adjust flow and controlling wellhead during the acid fracturing , water injection and well performance test .
it generally includes (form bottom to top)
► (One or ) two master valves
► a cross
► a swab valve
► a tree cap
all of this is completed by one or two wing valves and a choke. this set up allows:
► tools to be run in directly in line with the well provided a lubricator is screwed onto the tree cap connector .
► the well to be opened or shut via the wing vale .
► the flow rate to be controlled and adjusted via the choke bean .
► the well to be placed in safe condition via the master valves .
The number of valves and their location is not fixed and must be adapted to the safety and production requirement specific to each field . high pressures require two or even three master valves exceptionally, high flow rate mandate installing wing valve on both lateral outlets and lastly some cases demand continuous use of one or both outlets on the annulus .
The valves used on the Christmas tree are the gate valves type . during normal production , the lower master valve is kept open . the upper one is used to place the well in safe condition ; it is closed automatically by means of a hydraulic or pneumatic control system . the wing valve, often manual , can be motorized so that it can be remote controlled . apart from safety system tripping , the well is closed by acting on the wing valve then on the upper master valve . in contrast , the well is brought back on stream by opening the upper master valve then the wing value in order to “save” the upper master valve which is much more complicated and costly to replace than the wing valve.
When the equipment is chosen , the inside through diameters , working pressure , metallurgy and flow head configuration are given particular consideration :
► the inside vertical diameter must be at least the same as that of the tubing , the diameter of the wing valves being in proportion with those of the tubing and the flow lines .
► the rated working pressure (WP) is chosen depending on the highest pressure that could occur during the lifetime of the well, usually the shut – in wellhead pressure or the pressure prevailing during special operations . rate working pressure found on the market are 5000 psi WP (35 MPa ) , 10000 psi WP (70MPa) and now 15000 psi WP (100MPa) as per standards established by the American Petroleum Institute .
► the metallurgy and type of seals depend on the type of effluent and its temperature , the fire resistance and working pressure .
► choosing the configuration as such depends on safety conditions , floor space and production requirements .
Christmas tree have different components that all are included in NoDoC assemblies.
Wellhead equipment shall be designed and manufactured according to “API spec 6A” material and performance requirements . according to this standard four product specification levels ( PSLs) are introduced for wellhead requirements . these four product specification levels (PSIs) are introduced for wellhead requirements . these four PSLs are PSL1 , PSL2, PSL3, and PSL4 depending on pressure and severity of service condition like pressure and concentration of S , ….) . wellhead equipments are divided into pressure containing and pressure controlling parts depending on working pressure .
Those parts whose failure to function as intended would result in a release of retained fluid to the atmosphere are called pressure containing parts. examples are bodies , bonnets, and stems . pressure- controlling parts are those ones intended to control or regulate the movement of pressurized fluids , such as valve bore sealing mechanisms , choke trim, and hangers.
For instance you can see below what NoDoC includes for Christmas tree:
On oil and natural gas wells, it is usually necessary to establish a series of valves to control the pressure and rate of flow of the gas and / or oil from the reservoir that said “ Christmas tree” it is attached to the uppermost connection of the tubing head . Christmas tree is mainly used for production wellhead to control pressure and for the oil (gas ) wellhead to adjust flow and controlling wellhead during the acid fracturing , water injection and well performance test .
it generally includes (form bottom to top)
► (One or ) two master valves
► a cross
► a swab valve
► a tree cap
all of this is completed by one or two wing valves and a choke. this set up allows:
► tools to be run in directly in line with the well provided a lubricator is screwed onto the tree cap connector .
► the well to be opened or shut via the wing vale .
► the flow rate to be controlled and adjusted via the choke bean .
► the well to be placed in safe condition via the master valves .
The number of valves and their location is not fixed and must be adapted to the safety and production requirement specific to each field . high pressures require two or even three master valves exceptionally, high flow rate mandate installing wing valve on both lateral outlets and lastly some cases demand continuous use of one or both outlets on the annulus .
The valves used on the Christmas tree are the gate valves type . during normal production , the lower master valve is kept open . the upper one is used to place the well in safe condition ; it is closed automatically by means of a hydraulic or pneumatic control system . the wing valve, often manual , can be motorized so that it can be remote controlled . apart from safety system tripping , the well is closed by acting on the wing valve then on the upper master valve . in contrast , the well is brought back on stream by opening the upper master valve then the wing value in order to “save” the upper master valve which is much more complicated and costly to replace than the wing valve.
When the equipment is chosen , the inside through diameters , working pressure , metallurgy and flow head configuration are given particular consideration :
► the inside vertical diameter must be at least the same as that of the tubing , the diameter of the wing valves being in proportion with those of the tubing and the flow lines .
► the rated working pressure (WP) is chosen depending on the highest pressure that could occur during the lifetime of the well, usually the shut – in wellhead pressure or the pressure prevailing during special operations . rate working pressure found on the market are 5000 psi WP (35 MPa ) , 10000 psi WP (70MPa) and now 15000 psi WP (100MPa) as per standards established by the American Petroleum Institute .
► the metallurgy and type of seals depend on the type of effluent and its temperature , the fire resistance and working pressure .
► choosing the configuration as such depends on safety conditions , floor space and production requirements .
Christmas tree have different components that all are included in NoDoC assemblies.
