Abstract: A method for detecting water breakthrough in a well production. A model, of which the accuracy is known, will receive three of the four following parameters: inlet pressure, inlet temperature, outlet pressure, outlet temperature. The model includes a three-phase flash model including heat of evaporation of water and partial pressure of water with or without dissolved components lowering the vapor pressure such as salt and/or alcohol. Based on the three parameters the model computes the fourth parameter, whereupon the actual fourth parameter is measured and compared to the computed fourth parameter. If the deviation between the measured and the computed parameter is considerably larger than that which can be explained from the level of confidence of the selected model and uncertainty of measurement, it can be concluded that a water breakthrough has actually occurred.

Abstract: A method and a system to provide allocation of mixed flow to individual sources in oil and gas production systems by measuring mixed flow; analyzing the composition; accessing the data for the mixed flows; and calculating the flow from each source with an allocation algorithm using the mixed flow, the analyzed composition and the composition of at least one source.

Abstract: A method and a system to provide allocation of mixed flows back to individual sources in an oil and/or gas production system. The method is independent of sub sea on-line measurements. Instead the method uses comparably inexpensive topside equipment for compositional allocation of the flows. The method comprises the use of an on-line allocation algorithm. The method is suitable where improved reliability of flow allocation back to wells and reservoirs is needed. The allocated flow may be used to calculate and estimate the remaining volumes in a reservoir.

Abstract: Sensor failure in an oil and gas production system is monitored and detected by checking the consistency of the measurements of the sensor in question using a computer-based process model with the measurements of the other sensors in the system. The present invention also generates a back-up value for a failing sensor with the process model by identifying the value that is most consistent with the measurements of the other sensors in the system.

Abstract: Sensor failure in an oil and gas production system is monitored and detected by checking the consistency of the measurements of the sensor in question using a computer-based process model with the measurements of the other sensors in the system. The present invention also generates a back-up value for a failing sensor with the process model by identifying the value that is most consistent with the measurements of the other sensors in the system.