Data Historians
A data historian (also called a process historian) is a specialised database designed to store time-series data from industrial processes. In an oilfield, this means every pressure reading, temperature measurement, flow rate, and equipment status captured by sensors is stored with a precise timestamp - often at sub-second intervals.
How Data Historians Work
Data Ingestion
The historian receives data from SCADA systems, PLCs, and RTUs via standard protocols like OPC-DA, OPC-UA, or Modbus. Each data point is tagged with a unique identifier (e.g., WELL-A07.THP for tubing head pressure on Well A07).
Compression & Storage
Historians use lossy compression algorithms (like swinging door) to store only significant data changes, reducing storage requirements by 90%+ while preserving the shape of the data.
Example: If pressure holds steady at 1,500 psi for 2 hours, the historian stores only the start and end points - not thousands of identical readings.
Retrieval & Analysis
Engineers query the historian to retrieve historical trends, calculate averages, or export data for analysis. Modern historians provide APIs and connectors for Power BI, Python, and other tools.
Example: A production engineer retrieves 12 months of ESP motor temperature data for 50 wells to build a predictive maintenance model in Python.
Major Data Historian Products
OSIsoft PI (AVEVA PI)
The industry standard in oil and gas. Used by most major operators worldwide. Now part of AVEVA after acquisition by Schneider Electric.
Honeywell PHD
Honeywell's Process History Database, widely used in refining and upstream operations for high-speed data collection.
Aspen InfoPlus.21
AspenTech's historian, commonly paired with their process simulation and optimisation tools in integrated environments.
InfluxDB / TimescaleDB
Open-source time-series databases gaining traction for new digital oilfield projects, especially those built on cloud-native architectures.