WELL OPERATION METHOD USING PUMP SET WITH VARIABLE-FREQUENCY DRIVE AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2014 - IPC E21B43/00 F04B47/00 

FIELD: oil and gas industry.

SUBSTANCE: method lies in periodical repetition of cycles consisting of pumping, frequency search, stopping delivery and accumulation. At that in order to ensure pumping of fluid from the well equal to its influx the pump set is selected with a higher pump capacity in comparison with fluid influx from formation to the well. In process of cycles performance correction is made for pumping-accumulation time ratio depending on results of operation in the previous cycles until pumping-accumulation time ratio stops varying. The moment of stopping delivery is defined by equation of values of current torque at the shaft of a submerged electric motor and reference torque, which is determined preliminary against sudden drop of torque at the motor shaft at the point of stopping delivery at reduction of feed voltage frequency. The device contains a pump set consisting of a centrifugal pump and a submersible electric motor placed in the flow string and suspended at the sting of buried pipes. At that the submersible motor by its conducting cable is coupled to the frequency converter and control unit placed over the ground. Also the device contains a matching transformer, an evaluator of frequency, current, torque and power, a coupling unit, indication and control unit. At that the conducting cable is coupled to the first input-output of the matching transformer, which is coupled by its second input-output to the input-output of the frequency converter. The frequency converter by its second input-output is coupled to the power supply unit and by its third input-output to the first input-output of the evaluator of frequency, current, torque and power, which is by its second is coupled to the first input-output of the coupling unit, which second input-output is coupled to the fourth input-output of the frequency converter and the third input-output is coupled to the first input-output of the master controller, which second input-output is coupled to the indication and control unit. At that the device arranges receipt of all signals to the units placed above ground through the conducting cable directly from the shaft of the submersible electric motor.

EFFECT: improvement of the method efficiency and operational reliability of the device both in low- and high-yield wells.

2 cl, 3 dwg