ESP Thrust Washer Wear Protection

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Solution Overview

Problem

Existing electric submersible pumps (ESPs) face issues with thrust washer wear and failure, particularly in unfavorable conditions, leading to increased horsepower consumption and potential shaft damage due to metal-to-metal contact and heat generation, especially in sandy or unconventional wells.

Innovation Solution

The ESP design includes relocating the upthrust washer to a position closer to the impeller tip, using wear-resistant materials like phenolic or tungsten carbide, and incorporating lubrication grooves to enhance cooling and prevent shaft damage, along with a thicker downthrust washer to distribute axial thrust loads and prevent premature wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional thrust washers are used in ESP, then the pump can operate, but the thrust washers wear quickly and fail in unfavorable conditions leading to shaft damage

Engineering Contradiction:

Improvethrust washer durabilityVSAvoidshaft damage from metal-to-metal contact

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies composite materials by using phenolic material (a composite of resin and filler) for the upthrust washer instead of traditional metal materials. This composite material provides both thrust bearing capability and wear resistance, preventing metal-to-metal contact between the impeller and diffuser, thereby eliminating shaft damage while maintaining operational reliability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The phenolic upthrust washer acts as an intermediary element between the rotating impeller and the stationary diffuser. This intermediate component absorbs the thrust loads and prevents direct metal-to-metal contact, thereby mediating the harmful interaction that would otherwise lead to shaft damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If upthrust washer is positioned away from impeller tip, then assembly is easier, but thrust load distribution is poor causing premature wear

Engineering Contradiction:

Improvethrust washer installationVSAvoidthrust washer lifespan

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by positioning the upthrust washer at a specific location (adjacent to the impeller tip) where the thrust loads are most concentrated. This localized placement optimizes the thrust load distribution at the critical area, improving wear characteristics and lifespan without compromising assembly ease.

Inventive Principle:

Principle #3Local quality

3Force

If metal-to-metal contact occurs between impeller and diffuser, then thrust is handled, but heat is generated causing potential shaft damage

Engineering Contradiction:

Improvethrust handlingVSAvoidheat generation at thrust interface

Core Design Contradiction:

ForceVSTemperature

Solution Approach 1:

The patent replaces the mechanical metal-to-metal contact system with a phenolic composite material system. This substitution maintains the thrust handling capability while eliminating the harmful heat generation associated with metal friction, as the phenolic material provides low-friction, low-heat alternative.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the material parameter from metal to phenolic composite, which fundamentally alters the friction and heat generation characteristics. The phenolic material has lower friction coefficients and better heat resistance, thereby handling thrust loads while minimizing heat generation and preventing shaft damage.

Inventive Principle:

Principle #35Parameter changes

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

This configuration reduces the likelihood of shaft damage, maintains pump operation in upthrust conditions, and slows down wear rates by distributing thrust loads, thereby extending the lifespan of the ESP and preventing costly repairs.

Implementation Method 1

A balance ring of the impeller can include one or more lubrication grooves. The diffuser can include one or more lubrication grooves. A central hub of the diffuser can include one or more lubrication grooves in a leading or upstream edge of the central hub.

Methodology Applied

Scientific EffectLubrication: Lubrication

Implementation Method 2

one or more lubrication grooves to enhance cooling

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS11920599B2Thrust handling for electric submersible pumps

Publication Date: 2024.03.05 SCHLUMBERGER TECH CORP

AI summary

An electric submersible pump includes a plurality of centrifugal pump stages, each stage including a rotating impeller and a stationary diffuser mounted on a shaft coupled to a motor. An upthrust washer can be disposed axially between an impeller and its associated diffuser at or near a tip of the impeller, and the gap between the impeller tip and diffuser can define the end play or axial clearance for the pump. If the upthrust washer wears away, upthrust rubbing occurs at the impeller tip instead of proximate the pump shaft to advantageously help protect the shaft from damage or failure related to heat. In some ESPs, an upthrust bearing assembly can be located at the pump head. A downthrust washer can be disposed in an upstream facing groove of the impeller. The downthrust washer can have a thickness greater than 0.10 in.