ESP Seal Section Layout for Shaft Vibration and Leakage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrical submersible well pumps (ESP) face issues with shaft vibration and well fluid leakage due to mechanical face seals, leading to motor lubricant contamination and premature failure.
Innovation Solution
A submersible pump assembly with a seal section design that includes an outboard bearing for radial support and a shaft seal between the outboard and inboard bearings, utilizing a rotating and non-rotating face seal with a spring mechanism and wear-resistant carbide rings to prevent well fluid from entering the motor lubricant, along with a vent port for debris removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical face seal is used to seal well fluid from the seal section, then sealing performance is improved, but shaft vibration increases and leakage occurs due to vibration-induced fatigue
Solution Approach 1:
The seal section is divided into multiple functional zones: an outboard bearing providing radial support, a shaft seal positioned axially between bearings, and an inboard bearing. This segmentation allows each component to perform its specific function optimally, with the shaft seal isolated between bearings that dampen vibration, reducing vibration-induced leakage while maintaining sealing effectiveness.
Solution Approach 2:
The outboard and inboard bearings are positioned to provide radial support to the shaft before vibration can cause damage to the shaft seal. The bearings act as cushioning elements that absorb and dampen vibrations, protecting the mechanical face seal from vibration-induced fatigue and leakage before such damage occurs.
2Ease of manufacture
If the pump intake is located at the lower end of the pump, then conventional pump design is maintained, but well fluid can migrate through motor lubricant and contaminate the motor
Solution Approach 1:
The shaft seal acts as an intermediary barrier between the well fluid intake and the motor lubricant. Positioned axially between the outboard and inboard bearings, the shaft seal prevents well fluid from migrating through the motor lubricant, blocking the contamination pathway while allowing the pump intake to remain at the lower end for conventional design compatibility.
Solution Approach 2:
The harmful migration pathway of well fluid through the motor lubricant is extracted and blocked by the shaft seal. The seal removes the contamination risk by creating a distinct barrier that prevents well fluid from reaching the motor, allowing the pump to maintain its conventional lower intake configuration.
3Strength
If radial bearings are immersed in motor lubricant for shaft support, then shaft radial support is provided, but well fluid can leak past the mechanical face seal into the seal section and contaminate the lubricant
Solution Approach 1:
The shaft seal serves as an intermediary barrier between the well fluid environment and the motor lubricant. By positioning the seal axially between the outboard and inboard bearings, it prevents well fluid from leaking past the mechanical face seal into the seal section, thereby protecting the motor lubricant from contamination while maintaining shaft radial support through the bearing arrangement.
Solution Approach 2:
The seal section is segmented into distinct zones: the outboard bearing receives shaft radial support from well fluid, the shaft seal creates a barrier, and the inboard bearing provides additional support while preventing well fluid migration into the motor lubricant. This segmentation isolates the lubricant from well fluid contamination risks.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively reduces shaft vibration and prevents well fluid contamination of the motor lubricant, enhancing the reliability and longevity of the ESP by maintaining the integrity of the mechanical face seal and preventing debris accumulation.
Implementation Method 1
A spring urges the rotating face and the non-rotating face against each other
Implementation Method 2
The mechanical face seal has a rotating runner that is urged by a spring and diaphragm against a non-rotating base
Data Source
AI summary
A submersible pump assembly includes a pump, a motor, and a seal section connected between. A shaft passage in the seal section has an outboard end that is open to the pump intake and an inboard end that is in fluid communication with motor lubricant in the motor. A drive shaft extends axially within the shaft passage. An outboard bearing at the outboard end of the shaft passage receives the shaft to provide radial support. An inboard bearing at the inboard end of the shaft passage receives the shaft to provide radial support. A shaft seal in the shaft passage receives and seals around the shaft. The shaft seal is located between the outboard bearing and the inboard bearing and seals motor lubricant in the shaft passage from well fluid in the shaft passage.