What is Wellhead Control Panel (WHCP)? ? How does it work ?

What is Wellhead Control Panel (WHCP)?

It is a self‐contained panel integrated with necessary interlocking and sequence of operations logic functions, to operate each well string’s Surface Controlled Sub‐Surface Safety Valves (SCSSV), Surface Safety Valves (SSV) and/or Surface Wing Valves (WV).

At certain times it also provides the hydraulic supply to operate the platform’s Shutdown Valves (SDV), Blowdown Valves (BDV), Control Valves and Choke Valves.

It’s design is based on proven technique in electrical, hydraulic and pneumatic controls to operate, monitor and control the hydraulic pressure needed to open or close each well string.

Can be designed to suit the following conditions :

• Fully pneumatic, hydraulic or micro-processor based control.
• Pneumatic or hydraulic operated SSV and/or WV.
• Single or two stage hydraulic pressurization for SCSSV equalization operation.
• Linked to other sub-systems (e.g. Instrument Gas Skid (IGS), Diesel Generator, Chemical Injection System (CIS), Process Monitoring & Control System (PMCS), Safety Integrated System (SIS), etc…) for platform shutdown activation.

Understanding Well Head Control Panels (WHCP)

WHCPs are sophisticated systems dedicated to monitoring and controlling the key safety valves at the wellhead, including the Subsurface Controlled Safety Valves (SCSSV), Surface Safety Valves (SSV), and additional critical valves such as chokes and Emergency Shutdown (ESD) systems. These panels are engineered to be fail-safe, ensuring that in any scenario, whether it’s a malfunction or a hazardous event, the system defaults to a safe state, safeguarding personnel, the environment, and the equipment. Typically, WHCPs are integrated with advanced control technologies like PLC (Programmable Logic Controller) or SCADA (Supervisory Control and Data Acquisition) systems, providing precise and reliable management of the wellhead.

The operation of a WHCP involves interpreting signals from a variety of sensors that measure parameters like pressure, temperature, and flow rates at the wellhead. Inputs from emergency systems, such as ESD buttons or fusible plugs, are also crucial for the WHCP’s decision-making process. Based on these inputs, the WHCP can initiate actions like closing the wellhead valves to secure the well and prevent accidents.

WHCPs utilize both hydraulic and pneumatic mechanisms to control the wellhead valves. The choice between hydraulic and pneumatic systems often depends on the specific requirements of the well, with hydraulic systems being common for land-based operations due to their robustness and reliability.

Principle of Wellhead Control Panel (WHCP)  Operation

WHCPs can vary in their design and operational principles, often categorized by their power source—be it electric, manual, solar-powered, or pneumatically controlled. The selection of a WHCP type is dictated by the specific needs of the well and the environmental conditions. Additionally, WHCPs can be configured to manage a single wellhead or multiple wellheads simultaneously, providing flexibility in their application.

At the heart of a WHCP’s function is its ability to control the operation of wellhead valves, specifically the SCSSV and SSV, through a carefully orchestrated sequence. This control extends to managing emergency shutdown processes, ensuring the well can be safely secured in response to various triggers.

Main Functions of Wellhead Control Panel (WHCP)

The primary role of a WHCP is to enable the safe shutdown of the well in emergency situations, control critical safety parameters, and manage the sequential startup and shutdown of the wellhead. This is achieved through a combination of hydraulic power units, special control buttons, and precise monitoring of the SCSSV.

Components of Wellhead Control Panel (WHCP)

Located near the wellhead, the WHCP consists of several key components:

• Hydraulic Power Unit (HPU): Includes hydraulic pumps, reservoirs, and accumulators, crucial for distributing hydraulic fluid under pressure to operate the wellhead valves.
• Hydraulic Pumps: These pumps are responsible for delivering hydraulic fluid at the required pressures to the wellhead.
• Oil Reservoir: Stores the hydraulic oil needed by the pumps, equipped with strainers to ensure the cleanliness of the oil.
• Accumulator: An energy storage device that meets high-pressure demands for valve operation.
• Hydraulic Circuit: Comprises control valves, tubing, and supply headers, designed to handle various pressure levels required by the wellhead operations.

The WHCP interfaces with the wellhead’s instrumentation to monitor operations closely, using pressure transmitters and level gauges to ensure the system’s performance and safety.

Types of WHCP

WHCPs can be tailored to the specific needs of a well, with options ranging from manual to solar-powered systems. Each type offers distinct advantages, whether it’s the reliability of an electrical system, the simplicity of a manual setup, the energy efficiency of a solar-powered unit, or the high-power capability of a pneumatic system.

Design Wellhead Control Panel (WHCP) Considerations

Designing a WHCP involves careful consideration of component sizing, flowline safety, and the system’s testability. Safety features, such as chokes and pressure sensors, are integral to managing flowline pressures and ensuring the well’s integrity.

Build issues to consider:

Quite a lot of high valued out-sourced components for this panel.

Space limitation therefore tight panel layout design required.

Multi-discipline knowledge in instrumentation, controls, hydraulics and electrical will be necessary.

High pressure hydraulic for operating wellhead’s SCSSV, SSV and WV.

Hazardous area classification for all electrical components.

Codes and Standards compliance of Wellhead Control Panel (WHCP):

Compliance with codes and standards is fundamental in the design, installation, and operation of Well Head Control Panels (WHCP) in the oil and gas industry. These regulations ensure safety, reliability, and efficiency in the handling of wellhead operations, particularly given the high-risk environments where these systems are employed. This section outlines the key codes and standards relevant to WHCPs and their implications for compliance in oil and gas operations.

API 14C – Analysis, Design, Installation and Testing of basic Surface Safety Systems on Offshore Production Platforms

IEC 60529 – Classification of Degrees of Protection Provided by Enclosures

IEC 60079 – Electrical Apparatus for Explosive Gas Atmospheres

IEC 61508 – Functional Safety of Electrical/ Electronic / Programmable Electronic Safety-Related Systems

Conclusion

In the complex and hazardous environment of oil and gas production, WHCPs stand as critical guardians of safety and operational integrity. By precisely controlling the wellhead valves and managing emergency shutdowns, WHCPs help maintain continuous, safe production, ensuring that the extraction of valuable hydrocarbons proceeds without incident.