Rod-Driven Centrifugal Pump for SAGD Well Lift

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Solution Overview

Problem

Steam-assisted gravity drainage (SAGD) wells pose challenges due to high temperatures, viscous bitumen, abrasive particles, and corrosive gases, leading to short run lives and high costs for conventional Electrical Submersible Pumping (ESP) systems, which are inadequate for reliable artificial lift in these adverse conditions.

Innovation Solution

A rod-driven centrifugal pumping system with a downhole assembly including an adapter, receptacle shaft, up-thrust and down-thrust bearings, and a centrifugal pump, operated by a drive string rotated by a motor at surface speeds greater than or equal to 800 RPM, with a tensioner to stabilize the drive string, facilitating efficient pumping of production fluids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Electrical Submersible Pumping (ESP) systems are used in SAGD wells, then pumping capability is provided, but run life is short and cost is high

Engineering Contradiction:

Improverun lifeVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the electrical ESP system with a mechanically driven centrifugal pump system. The drive string transmits mechanical rotation from surface through the production tubing to the centrifugal pump, eliminating the need for electrical components downhole. This mechanical substitution improves reliability by using simpler, more robust components suitable for high-temperature, abrasive environments, while reducing costs by eliminating expensive electrical motors and associated infrastructure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If conventional pumping systems are used in high temperature environments, then fluid extraction is achieved, but system durability decreases

Engineering Contradiction:

Improvefluid extractionVSAvoidsystem durability

Core Design Contradiction:

ProductivityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the operating parameters and environmental conditions the system is designed to withstand. The centrifugal pump and drive string components are specifically engineered to operate in high-temperature, high-pressure, and abrasive conditions typical of SAGD wells. By adjusting the system design parameters to match the adverse well conditions rather than trying to protect against them, the system achieves both high productivity and extended durability.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If drive string rotation speed is increased to improve pumping efficiency, then fluid production increases, but drive string stability decreases

Engineering Contradiction:

Improvepumping efficiencyVSAvoiddrive string stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent employs a tensioning system that applies controlled axial tension to the drive string, counteracting the destabilizing effects of high-speed rotation. The tensioning mechanism creates a stabilizing force that maintains drive string alignment and prevents excessive vibration or buckling, allowing the system to operate at high rotation speeds needed for efficient pumping while maintaining structural stability.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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 system provides a more reliable and cost-effective artificial lift solution for SAGD wells by enhancing the longevity and efficiency of fluid extraction, reducing operational costs and maintaining stability under harsh conditions.

Implementation Method 1

rod driven centrifugal pumping system

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

drive string rotated by a motor at surface speeds greater than or equal to 800 RPM

Methodology Applied

Scientific EffectMechanical energy transmission: Mechanical Force

Implementation Method 3

tensioner to stabilize the drive string

Methodology Applied

Scientific EffectTension: Tension

Data Source

PatentUS10550675B2Rod driven centrifugal pumping system for adverse well production

Publication Date: 2020.02.04 OILFIELD EQUIP DEVMENT CENT

AI summary

A downhole assembly of an artificial lift system includes: an adapter for connection to production tubing; a receptacle shaft; an up-thrust bearing; a centrifugal pump; and a down-thrust bearing. The receptacle shaft has a latch profile for receiving a latch fastener of a drive coupling and a torsional profile for mating with the coupling to longitudinally and torsionally connect thereto. The up-thrust bearing includes: a thrust driver longitudinally and torsionally connected to the receptacle shaft; and a thrust carrier connected to the adapter. The centrifugal pump includes: a diffuser connected to the adapter; a pump shaft torsionally connected to the receptacle shaft; and an impeller connected to the pump shaft. The down-thrust bearing includes: a thrust driver longitudinally and torsionally connected to the pump shaft; and a thrust carrier connected to the adapter.