Oil and Gas Flow Computer Library
The dual flow computer library provides gas and crude oil flow computer features for Wago PFC200 controllers.
The library performs API 12 crude oil calculations for custody-transfer meters or API 20.1 calculations for allocation meters, and AGA-3/AGA-8 orifice meter calculations. Events, alarms, and hourly history are maintained in a manner consistent with API 21.1. Data is extracted from the PLC using industry-standard .cfx files.
Gas Flow Computer Feature Summary
For gas calculations, the library uses the concept of stations and meters. Stations describe gas properties and base conditions. Meters are assigned to Stations. At present, only orifice meters are supported.
| Meter Calculations | Orifice flow calculations | per AGA-3 (2013) |
| Meter calculation frequency | Full once per second | |
| Calculated parameters | Volume, Mass, Energy | |
| Aggregated values available | Flow Rate, Current Hour Total, Last Hour Total, Today Total, Yesterday Total, Current Month Total, Prior Hour Total, Lifetime Total | |
| Gas Property Calculations | Supercompressibility and density | per AGA-8 GERG (2017) |
| Gas property calculation frequency | Full calc once per second | |
| Gas Property Calculation Frequency | Full calc during each PLC task cycle | |
| Supported Meter Configurations | Orifice Meter | Flange taps |
| Upstream static pressure tap | ||
| Contract Hour | Configurable | Per station |
| Units of Measure | Customary U.S. units only | Inches, psi, inches of water (68 degrees), degrees F, flow rates per day, volumes in MSCF, energy in MMBTU, mass in Mlbs |
| Diagnostics | Station calculations | Zs, Densitys, Zb, Densityb, Gas Gravity from Composition – corrected for standard conditions |
| Meter configuration | Zf, Densityf, , Re, Cd, Ev, Y1, Fpv , Temperature-corrected Orifice size, Tube size, Beta | |
| Configuration validation features | Library validates configuration and provides error/warning messages |
Oil Flow Computer Feature Summary
For oil calculations, the library supports meter input as either a flow rate or an accumulated volume. Input can be related to either mass or indicated volume. This arrangement accommodates Coriolis, Turbine, and Positive Displacement meters. The meter can be configured as either a custody-transfer meter or an allocation meter.
| Meter Calculations | per API 12.2 for custody transfer or API 20.1 for allocation | |
| Meter calculation frequency | Full calc once per second | |
| Calculated parameters: custody transfer | Indicated Quantity, Indicated Volume, Gross Volume, Gross Standard Volume, Net Standard Volume, S&W Volume, Gross Mass | |
| Calculated Parameters: allocation | Indicated Quantity, Indicated Volume, Gross Volume, Gross Theoretical Oil Volume, Net Theoretical Oil Volume, Gross Theoretical Water Volume, Theoretical Flash Gas Volume | |
| Aggregated values available | Flow Rate, Current Hour Total, Last Hour Total, Today Total, Yesterday Total, Current Month Total, Prior Hour Total, Lifetime Total | |
| Oil Property Calculations | Liquid Correction Factors (CRUDE OIL ONLY) | per API 11.1 Table A (2004) |
| Water Property Calculations | Water Correction Factors | per API 20.1 |
| Supported Meter Configurations | Coriolis, Turbine, Positive Displacement | |
| Contract Hour | Configurable | Per meter |
| Units of Measure | Customary U.S. units only | psig, degrees F, API gravity, barrels per day, mass in lbs |
| Diagnostics | Correction Factors | Corrected Density, CTL, CPL, CTPL, CSW, Standard Density |
Generic Feature Summary
| Data Retention | per API 21.1 | Periodic (hourly) history, events, alarms |
| Periodic history retention | Configurable by meter. Minimum of 35 days – ranging to file system capacity | |
| Event retention | 256 events per meter per “day” | |
| Alarm retention | 64 alarms per meter per “day” | |
| Data Transfer Method (Collection) | Via CFX files | Quorum/FLOWCAL Common File Exchange Format 8.5.0 |
| Minimum of 1 CFX per day | ||
| CFX file stored on PLC file system (password protected) | ||
| Manual/Local collection | Users with limited permissions and network access can copy CFX files from the PLC to another computer for transfer to hydrocarbon accounting system | |
| Remote/SCADA collection | Via secure FTP or SSH | |
| SCADA Interface | Implemented in PLC program | |
| Configuration Loading/Transfer | Via text file | Library provides features to save configuration to file |
| Library provides features to load all or part of the configuration from file | ||
| Power Loss Behavior | Configuration is retained | PLC persistent memory |
| Flow History is retained | PLC persistent memory and file system | |
| Flow that occurs while PLC is not powered | Not measured | |
| When power is restored | Broken day is saved as CFX file and calculations resume | |
| Licensing | Free for developer | Library file is free and can be added to any Wago e!COCKPIT instance |
| Runtime Licensed | Library generates a site code on the PLC | |
| Beyond HMI, Inc. generates a license file from site code | ||
| License file is installed on the PLC. License is perpetual but only usable on that PLC. | ||
| Library features will execute for about 4 days after restart in trial mode. License must be installed before this period expires or data will be lost (unrecoverable). |
Licensing
The BhiLibDualFc library is available at no cost to e!COCKPIT users. The library uses runtime licensing. A license is required for each PLC which executes the library code. The program will run for approximately 4 days in trial mode before a license is required. Licenses must be purchased from Beyond HMI, Inc.