This calculation mode allows the user to compute the Gas Oil Ratio (GOR) as defined through a series of user-defined flash calculations specified on keyword GOR statements. In PROVISION, this data may be entered or modified in the Gas Oil Ratio Data group of the window shown here.
The GOR is computed by collecting all the gas from the flash points and calculating the vapor volume rate using the stream thermo at reference conditions, as if it were all vapor and dividing that by the liquid volume flow of the last flash calculated at reference conditions. The GOR value and the declared products of the UPSTREAM unit are accessible to the CALCULATOR, CONTROLLER, MVC, and OPTIMIZER, allowing the user to perform other calculations with these results.
Liquid Reference Pressure and Temperature
Specifies the reference conditions (pressure and temperature) for the computation of the volume of the last liquid in the GOR mode. Defaults to STDPRESSURE and STDTEMP parameter values given in the General Data Section of input.
Vapor Reference Pressure and Temperature
Specifies the reference conditions (pressure and temperature) for the computation of the ideal vapor volume in the GOR mode. Defaults to STDPRESSURE and STDTEMP parameter values given in the General Data Section of input.
Thermal Conditions for Flash Calculations:
Use this grid to specify the temperature and pressure conditions for each of the flashes (excluding reference states). A maximum of 100 Temperature/Pressure points can be entered.
The feed(s) to the unit are combined and flashed at the first set of thermal conditions. The resulting liquid stream is flashed at the second set of thermal conditions, and the process repeats until all thermal conditions have been processed at which point the GOR value is calculated at the specified reference thermal conditions.
The GOR computation uses the liquid volume (at reference temperature and pressure for the liquid) using the composition of the liquid produced by the last flash. For this volume calculation, the fluid should be totally liquid. If however the fluid vaporizes at the reference conditions, a warning message is issued. If water is present in the system, it will be decanted during each flash calculation; however, the vapors and the last liquid will be saturated with water and this will affect the value of the computed GOR. If the liquid phase disappears at any set of conditions, a zero GOR value is produced and a warning message is given. None of the declared Product stream are calculated in this event.