Electric submersible pump fault diagnosis problem
1 Problems in the diagnosis technology of electric submersible pump
1.1 Problems in the traditional electric submersible pump fault diagnosis method
1.1.1 Problems in the current card diagnostic method
The current card diagnostic method uses a limited range of limitations, can only explain for some specific faults, and can not accurately and comprehensively analyze the entire system fault, and can not make a clear explanation for the real cause of the fault. For example, when the electric submersible pump needs to be turned on again due to reasons, it is easy to enlarge the original fault, and it is impossible to provide accurate fault guidance to the on-site maintenance personnel, and it is difficult to take effective solutions.
1.1.2 Problems in the diagnosis method of rolling pressure
The main method of dialysis diagnosis is to test the pressure generated by the unit after the wellhead production valve is closed to judge whether the electric submersible pump has a fault problem. However, if the time is too long, the formation pressure around the oil well will fluctuate. It takes a long time to start the machine again to restore the formation pressure to normal. This situation is not conducive to effective mining of the well. Moreover, this method can not directly monitor the entire electric submersible pump unit, but simply rely on the curve generated between the wellhead pressure and time to speculate, that is to say, the fault analysis estimated by this method lacks certain Intuitive and accurate, each test takes a long time.
2.2 Problems in modern electric submersible pump fault diagnosis technology
2.2.1 Problems in the fault tree diagnosis method
The fault tree diagnosis method mainly relies on the computer analysis technology, and the data source is mainly generated by the faulty unit. The fault tree diagnosis method is advantageous for the whole ESP unit, and can accurately analyze the normal and fault conditions, but can not make a correct analysis for the local fault situation. In this case, the mathematical model will be established. There is a big difference. It is preferable to use the fault tree diagnosis method in a state in which the components of the electric submersible pump do not affect each other, but the actual situation is exactly the opposite, and the connection between the components of the electric submersible pump is very tight. The electric submersible pump fault tree adopts the quantitative calculation method, which requires collecting a large amount of data, so as to accurately calculate the probability of component failure, but the disadvantage is that once the working environment of the electric submersible pump changes, Then the data collected before can no longer be used, and needs to be re-collected and calculated, which is a waste of time.
2.2.2 Problems in the diagnosis of fuzzy mathematics
The fuzzy mathematics method is not flexible, which means that it is easy to produce omissions in the process of diagnosis. It is mainly for the occurrence of new faults. Once a new fault occurs, this diagnostic method is not applicable. After all, establishing a relationship matrix is necessary. Relevant statistics and experience can be used to establish effective coefficients. If new coefficients cannot be obtained, the limitations and uncertainties are very obvious.