SCADA Systems
SCADA (Supervisory Control and Data Acquisition) is the central nervous system of a digital oilfield. It connects field instruments to a central control system, enabling operators to monitor, control, and manage remote wells and facilities from a single location.
SCADA Architecture
Field Instruments (Level 0)
Sensors, transmitters, actuators, and valves physically connected to wells and equipment. These are the "eyes and hands" of the system.
Example: A Rosemount pressure transmitter on a wellhead sends a 4-20 mA signal proportional to tubing head pressure.
RTU / PLC (Level 1)
Remote Terminal Units (RTUs) or Programmable Logic Controllers (PLCs) at each well pad collect sensor data, execute local control logic, and communicate with the SCADA master.
Example: An RTU at a remote desert wellhead collects pressure, temperature, and flow data, stores it locally if the satellite link drops, and resends when connectivity is restored.
Communication Network (Level 2)
Radio, satellite (VSAT), cellular (4G/5G), fibre optic, or microwave links connect remote RTUs to the central SCADA server. Reliability and latency are critical considerations.
Example: A VSAT satellite dish at each offshore platform provides the communication backbone for SCADA data to reach the onshore control centre.
SCADA Master / HMI (Level 3)
The central SCADA server processes incoming data, executes control commands, triggers alarms, and presents everything through a Human-Machine Interface (HMI) - the screens operators use in the control room.
Example: An operator in the control room sees an alarm on the HMI - casing pressure on Well-A07 has exceeded 1,500 psi. They remotely close the wing valve via SCADA.
What Can SCADA Do?
Monitoring
- • Live pressure, temperature, and flow readings
- • Equipment status (running, stopped, fault)
- • Tank levels and pipeline conditions
- • Alarm management and event logging
Control
- • Remote well start/stop
- • Choke and valve adjustments
- • ESP speed changes
- • Emergency shut-in procedures
Common SCADA Vendors in Oil & Gas
ABB
Ability Symphony Plus
Emerson
DeltaV / OpenEnterprise
Honeywell
Experion PKS
Siemens
WinCC / SIMATIC