A system and method are provided. The system includes a feature calculator calculates features of a Pressure Volume diagram. The system further includes a pumpjack condition separator separates normal pumpjack conditions from abnormal pumpjack conditions using a hierarchical decision tree, the conditions being determined using the features. The system also includes a compound indicator generator generates a compound indicator when a predetermined number of at least one of features and conditions exceed respective thresholds. The system additionally includes an abnormal PV diagram indicator provides a user-perceptible indication that the PV diagram is abnormal when the compound indicator exceeds a compound indicator threshold.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A system, comprising: a feature calculator calculates features of a Pressure Volume diagram; a pumpjack condition separator separates normal pumpjack conditions from abnormal pumpjack conditions using a hierarchical decision tree, the conditions being determined using the features; a compound indicator generator generates a compound indicator when a predetermined number of at least one of features and conditions exceed respective thresholds; and an abnormal PV diagram indicator provides a user-perceptible indication that the PV diagram is abnormal when the compound indicator exceeds a compound indicator threshold. 2. The system of claim 1, further comprising: a pressure and volume database stores operating data on pressures and volumes for a pumpjack; and a database of abnormal conditions stores historical data of abnormal pumpjack conditions, wherein the feature calculator calculates the features of the Pressure Volume diagram using the operating data and the historical data. 3. The system of claim 2, further comprising a threshold tuner for performing threshold tuning using the historical data of abnormal pumpjack conditions stored in the database of abnormal conditions. 4. The system of claim 1, wherein different alarms are set for different ones of the features and the conditions, and the system further comprises an operation manager for managing an operational state of the pumpjack responsive to at least one of the user-perceptible indication, PV diagram data, a number of set alarms and a type of specific alarms that are set. 5. The system of claim 1, wherein the features comprise key features and non-key features. 6. The system of claim 1, wherein the features of the PV diagram are calculated using a union-based technique. 7. The system of claim 1, wherein the features of the PV diagram are calculated using a convex hull-based technique. 8. The system of claim 7, wherein the convex hull-based technique comprises: finding a point in the PV diagram with a median x coordinate; computing a convex hull of each of two halves determined with respect to the median x coordinate; and combining the convex hull of each of the two halves by finding common tangents in the two halves. 9. The system of claim 1, wherein the features of the PV diagram are calculating using a simplification technique. 10. The system of claim 9, wherein the simplification technique comprises at least one of simplifying by removing changes in angles greater than a first threshold, simplifying by removing changes in areas greater than a second threshold, and simplifying by removing a set of least important features. 11. The system of claim 9, wherein simplification technique increasingly simplifies the PV diagram to provide a plurality of simplified representations of the PV diagram from which the features are calculated. 12. The system of claim 1, wherein the features of the PV diagram are calculated using a union-based technique, a convex hull-based technique, and a simplification technique. 13. The system of claim 12, wherein the compound indicator is determined based on the union-based technique, the convex hull-based technique, and the simplification technique. 14. The system of claim 1, further comprising a validator for validating whether a given one of the abnormal pumpjack conditions is a valid false alarm, and marking the given one of the abnormal pumpjack conditions for threshold re-tuning. 15. A method, comprising: calculating, by a feature calculator, features of a Pressure Volume diagram; separating, by a pumpjack condition separator, normal pumpjack conditions from abnormal pumpjack conditions using a hierarchical decision tree, the conditions being determined using the features; generating, by a compound indicator generator, a compound indicator when a predetermined number of at least one of features and conditions exceed respective thresholds; and providing, by an abnormal PV diagram indicator, a user-perceptible indication that the PV diagram is abnormal when the compound indicator exceeds a compound indicator threshold. 16. The method of claim 15, wherein different alarms are set for different ones of the features and the conditions, and the system further comprises an operation manager for managing an operational state of the pumpjack responsive to at least one of the user-perceptible indication, PV diagram data, a number of set alarms and a type of specific alarms that are set. 17. The method of claim 15, wherein the features of the PV diagram are calculating using a simplification technique that increasingly simplifies the PV diagram to provide a plurality of simplified representations of the PV diagram from which the features are calculated. 18. The method of claim 15, wherein the features of the PV diagram are calculated using a union-based technique, a convex hull-based technique, and a simplification technique. 19. The method of claim 18, wherein the compound indicator is determined based on the union-based technique, the convex hull-based technique, and the simplification technique. 20. A non-transitory article of manufacture tangibly embodying a computer readable program which when executed causes a computer to perform the steps of claim 15.