This paper provides an overview of the qualification process of the highest power ESP ever installed into a hydrocarbon production system for artificial lift. The unit was selected and configured to interface with the existing deepwater offshore inflow and outflow systems without changes to the completion string or riser. The overall objective was to maximize the production capacity in terms of lift and flow rate given topsides power supply and running diameter constraints. The initial requirement was to identify a suitable supplier that could provide a hardware solution with a high technical readiness level. The team first reviewed the hydraulic performance of the existing production systems and modeled the potential for improvement with the new equipment configuration given an expected efficiency and power factor for the proposed motor. The ESP equipment was configured with components that had multiple qualification and validation testing requirements. The motor and associated high voltage connector were key differences from the existing systems. The pump design was modified to accommodate projected operating ranges including additional stages for the necessary head requirements. The new subcomponents were subjected to application specific testing to qualify the designs for operating conditions with multiple technical assurance reviews conducted by the end user and supplier company technical discipline authorities. Full scale flow testing at a dedicated facility (Gasmer) for Caisson gas/liquid separator ESP systems, and component installation stackup tests for fit and interfaces were completed to validate the performance in multiphase flow and identify hardware changes needed for the completion design and the intervention procedures. The qualification program was completed successfully, and a unit was deployed without incident, into a deepwater mudline caisson that has since been operated for live hydrocarbon production. The performance has met expectations and the unit efficiency and demonstrated capacity will allow for increased production. The use of a detailed qualification program that includes focused testing for individual system components and validation through full scale system integration testing ensures flawless deployment of technology improvements for critical well applications. The system is the highest power ESP for hydrocarbon production. It includes a novel completion design to accommodate the effective running diameter for the motor. The use of a unique shroud design to stay within running diameter constraints allowed for minor modifications to the completion string design without system changes to the riser or caisson. This was both cost effective and reduced the time needed for development and manufacturing.

This paper describes the technology and processes used to identify in a timely matter the source of an Instantaneous Over Current (IOC) trip during an ESP re-start at Shell Perdido SPAR. Monitoring health condition of subsea ESPs is challenging. ESPs operate in harsh and remote environments which makes it difficult to implement and maintain any in-situ monitoring system. Shell operates five subsea ESPs and implemented a topside conditioning monitoring system using electrical waveform analysis. The Perdido SPAR had a scheduled maintenance shutdown in April 2019. While ramping the facility down on April 19, 2019 the variable frequency drive (VFD) for ESP-E tripped on a cell overvoltage fault. The cell was changed, but the VFD continued to trip on instantaneous overcurrent. During ramp up beginning April 29, 2019 most equipment came back online smoothly, but the VFD of the particular ESP labeled ESP-E continued to experience the problem that was causing overcurrent trips, preventing restart. Initial investigations could not pinpoint the source of the issue. On May 1, 2019 Shell sought to investigate this issue using high-frequency electrical waveform data recorded topside as an attempt to better pinpoint the source of this trip. Analysis of electrical waveform before, during and after the IOC trip found an intermittent shorting/arcing at the VFD and ruled out any issues with the 7,000-foot-long umbilical cable or ESP motor. Upon further inspection, a VFD technician was able to visually identify the source of the problem. Relying in part on electrical waveform findings, VFD technician found failed outer jackets in the MV shielded cables at the output filter section creating a ground path from the VFD output bus via the cable shield. The cables were replaced, and the problem was alleviated allowing the system to return to normal operation. Shell credits quick and accurate analysis of electrical waveform with accelerating troubleshooting activities on the VFD, saving approximately 1-2 days of troubleshooting time and associated downtime savings, that translate to approximately 50,000 BOE deferment reduction. Analysis of high-frequency electrical waveform using physics-based and machine learning algorithms enables one to extract long-term changes in ESP health, while filtering out the shorter-term changes caused by operating condition variations. This novel approach to analysis provides operators with a reliable source of information for troubleshooting and diagnosing failure events to reduce work-over costs and limit production losses.

This paper provides the validation test results of preheat sequence applied to induction motors at two Test Facilities and offshore application for operation in the Gulf of Mexico. Although the objective of preheating Induction Motors (IM) is to lower the viscosity of the lubricant oil by 2 orders of magnitude (from 1000 cP to 10cP) for extending Electric Sumersible Pump (ESP) run life, this paper is exclusively focused on motor preheating results. The motor is energized with low voltage at a frequency of 120Hz maintaining the voltage low enough in order to keep the supplied shaft torque under the system's breakaway torque; thus the shaft never spins. The Medium Voltage Drive (MVD) is a Variable Frequency Drive output power determines heat rate that is adjusted to obtain temperature slope of 1°F/min specified by the project. The motor is modeled electrically and magnetically through Finite Element Analisys (FEA) to estimate its power losses; the motor internal temperatures can be predicted by the Motor-CAD (Computer-Aided Design) thermal model which is calibrated by winding resistance change and skin tempeperature measurement. The systems for validation were: First test facilities: 1500hp Induction Motor coupled to a pump and driven with a 2500hp MVDSecond test facilities: 1500hp Induction Motor coupled to a dyno and driven with a 2500hp MVD.Offshore: Five 1500hp ESPs driven with 2500hp MVD each. The results at first and second test facilities and offshore in the Gulf of Mexico demonstrate the preheat sequence can be successfully implemented in the field by using existing MVD with little software changes in order to apply low voltage at 120Hz without spinning the rotor. The stator current and induced current on the rotor make motor internal temperature (including lubricant oil) to rise achieving different temperature slopes. Temperature slopes vary in function of applied motor current (there was no need of overpassing motor nominal current on any test), motor thermal capacity, initial motor temperature, and external temperature. All tested motors are very similar and was found that Keeping heating power at around 34kW, winding temperature rise can be achieved at a rate of 1.52°F/min at an initial temperature of 38°F and 1.2°F/min at an initial temperature of 148°F. Temperature rise rate at the motor air gap (actually filled with oil) and bearings location can also be predicted by the motor thermal model. The required preheating time is previously calculated to reach less than 10cP viscosity of lubricant oil to guarantee safe startup without the occurrence of bearing spin; otherwise bearing friction torque overcomes the T-ring retaining torque causing bearing(s) damage. When the need of preheating the induction motor of electric submersible pumps installed in deepwater applications was identified, there was no clear means to make it possible. This was the first time that concept was applied and successfully implemented in the field. A second milestone was to preheat the motor with the MVD without adding equipment. Among five potential methods for preheating the motor, the selected scheme worked as expected with minimum MVD software changes.