FLUSHING METHOD OF WELL SUBMERSIBLE ELECTRIC CENTRIFUGAL PUMP Russian patent published in 2014 - IPC E21B41/02 E21B37/06 

FIELD: oil and gas industry.

SUBSTANCE: invention is related to oil and gas industry and is focused on increase in efficiency of operation of submersible electric centrifugal pumps which is complicated by formation of asphaltene, resin and paraffin deposits on the pump actuating elements. It is suggested to use hot oil as a reagent dissolving deposits in technology of dynamic impact. To this end chambers having similar volume with an electric heating element and temperature sensors are installed preliminary above and below the submersible pump. After shutdown of the electric centrifugal pump the borehole oil is heated up to the required temperature in the lower chamber and transferred through the pump cavity to the upper heating chamber by the same pump. In order to decrease flow rate of hot oil through the pump cavity pumping capacity is decreased by means of current frequency controller. With the three-position reverse-flow valve installed above the upper heating chamber hot oil is returned back to the lower chamber from the well head by means of portable pump unit of TSA-320 type. When there is no three-position reverse-flow valve installed above the upper heating chamber hot oil is returned back to the lower chamber by gravity flow. The period of hot oil cyclic impact on deposits inside the cavity of the submersible electric centrifugal pump shall be equal to time required for complete dissolving of asphaltene, resin and paraffin deposits. This time is determined preliminary in laboratory conditions with well conditions modelling.

EFFECT: periodic use of this method at wells complicated with deposits allows increase in their failure-free operation.

3 cl, 1 dwg