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ESP With Backup Oil Heating System

IP.com Disclosure Number: IPCOM000237690D
Publication Date: 2014-Jul-02
Document File: 2 page(s) / 86K

Publishing Venue

The IP.com Prior Art Database

Abstract

Well fluid contamination is one of the primary causes of ESP failure, especially in motors. Well fluid enters and exits the ESP seal section as required to maintain a pressure equilibrium between the motor oil and well fluid. While the motor is at operating temperature, very little flow occurs between the seal and wellbore. However, during ESP shutdown, the motor and seal may cool down to the bottom hole temperature, which can be up to 100F or more below the motor operating temperature. This cooling can cause significant volume reduction of the motor oil, resulting in the ingress of well fluid into seal section. Given sufficient startup/shutdown cycles, the well fluid may eventually penetrate through barriers such as bags, chambers, check valves or face seals, resulting in motor contamination. A means to prevent cooling of the motor and seal section during shutdown would reduce this failure mode. This invention is for providing a backup heat source to prevent motor oil shrinkage in the ESP motor and seal during ESP shutdown.

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ESP With Backup Oil Heating System

Well fluid contamination is one of the primary causes of ESP failure, especially in motors. Well fluid enters and exits the ESP seal section as required to maintain a pressure equilibrium between the motor oil and well fluid. While the motor is at operating temperature, very little flow occurs between the seal and wellbore. However, during ESP shutdown, the motor and seal may cool down to the bottom hole temperature, which can be up to 100F or more below the motor operating temperature. This cooling can cause significant volume reduction of the motor oil, resulting in the ingress of well fluid into seal section. Given sufficient startup/shutdown cycles, the well fluid may eventually penetrate through barriers such as bags, chambers, check valves or face seals, resulting in motor contamination. A means to prevent cooling of the motor and seal section during shutdown would reduce this failure mode. This invention is for providing a backup heat source to prevent motor oil shrinkage in the ESP motor and seal during ESP shutdown.

During ESP shutdown, the motor and seal may cool down to the bottom hole temperature, which can be up to 100F or more below the motor operating temperature. This cooling can cause significant volume reduction of the motor oil, approximately 5 per 100F, amounting to a quart or more for a large motor and seal that must be replaced by well fluid. While most of the well fluid is routed as intended to the outside of the top bag or the bottom of the top chamber, some inevitably penetrates through barriers such as ba...