Wellhead Control Panels (WHCPs) - Pneumatic / Hydraulic Offshore/Products
Wellhead systems serve as the termination point of casing and tubing strings. As such, these systems control pressure and provide access to the main bore of the casing or tubing or to the annulus.
This pressure-controlled access allows drilling and completion activities to take place safely with minimal environmental risk. Multiple barriers are used, such as primary and secondary seals, to reduce risk in case of equipment failure.
Types of wellhead systems
Wellhead systems differ by well location:
- - Land
- - Surface locations offshore (jackup or platform)
- - Subsea
Offshore wellhead systems are normally more sophisticated in design to handle ocean currents, bending loads, and other loads induced by the environment during the life of the well. Some of these loads are cyclic in nature, so fatigue-resistant designs are desirable, particularly for deepwater developments. Material specifications play an important role in equipment performance; helpful standards are available from organizations such as:
- - American Petroleum Institute (API)
- - American Society of Mechanical Engineers (ASME)
- - National Association of Corrosion Engineers (NACE Intl.)
In certain applications such as deepwater platforms, spars, and tension-leg platforms (TLPs), surface wellheads and subsea wellheads are used together to safely produce hydrocarbons. In water depths of 500 to 1,400 ft, subsea wellheads are used to explore and develop offshore fields. Deepwater production platforms can be placed over these wells and tied back to the subsea wellheads; the top termination of the tieback at the platform will typically use surface unitized wellheads with solid block Christmas trees (which have fewer leak paths) as pressure-controlled access points to each well.
Spars and TLPs are floating vessels used in deep water up to 4,500 ft. The wells are drilled using subsea wellheads, which are then tied back to the production deck of the spar or TLP, again using unitized wellheads and solid block trees to safely control and produce the well. For these special applications, it is recommended to contact your equipment supplier for more detailed information.
CONTROL SYSTEMS & CONTROL PANELS
Wellhead control panel is key equipment in oil & gas industry to protect oilfield facilities and environment from wellhead fire and emergencies, which is one of main control systems to ensure smooth oilfield oil production. Mowe manufacture wellhead control systems and panels to safety operational international standards and national regulations.
Wellhead control panel is composed of the following main design types for the purpose of operating and shutting SSVs including MSSV, WSSV and SCSSV.etc.
- Hydraulic Systems
- Hydraulic + Pneumatic Systems
- Hydraulic or Hydraulic + Pneumatic Systems with Processor Controlled logics
- - Local On/Off SSV
- - Remote control SSV through RTU
- - High-Low pressure sense shut-down automatically.
- - Fusible Plug, Anti-fire Shut-down automatically.
- - SSV can not be opened unless local reset after shutoff
- - Function of showing system pressure
- - Relief Valve shall be installed on each hydraulic circuit to prevent high pressure
- - Function of showing hydraulic level and level switch for alarm
- - Function of defending pressure impact of system
- - Function of defending exorbitant pressure
- - Function of system pressure monitoring(by pressure transmitter of control panel)
- - Function of remote emergency shut-down (by magnetic valve of control panel)
- - Function of On/Off SSV monitoring (by pressure switch of control loop of control panel)
- - Function of shield High-low pressure sense
Single Wellhead Control Panels
Single wellhead control panel is used for controlling one well Surface controlled sub-surface safety valve (SCSSV), Master SSV and Wing SSV. SSVs can be shutdown automatically and manually by WHCP to response all kind of emergency situation.
Single well control panel is categorized the following system according to driven resource:
- - Manual control system
- - Electrical control system
- - Pneumatic control system
- - Option for Solar powered control system
- - WHCP main functions include Hi/Lo pressure Shutdown, fire fusible plug protection and remote ESD etc.
Multi-Wellhead Control Panels
Each control module is draw able and can be inter-replaceable without any interruption of other well operation. Common module include oil reservoir, Pneumatic hydraulic pump and standby manual pump. Main function shows as following:
- - Remote RTU shutdown;
- Fire fusible plugs protection
- Low pressure / high pressure sensing
- Manual control at panel
- 2 to 32 wells of various designs
Illustration of WellHead Panel Operational Diagram
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