Passive Multiphase Separator Using Rifled Surface

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Solution Overview

Problem

Existing downhole gas separators in oil and gas production often rely on driven shafts, which may not be present in all applications, leading to inefficiencies in gas separation, particularly in wells with elevated gas fractions, causing issues like cavitation and vapor lock due to centrifugal forces.

Innovation Solution

A passive multiphase separator with a rifled interior surface and a head assembly that includes a crossover tube and gas vents, allowing for gas separation without the need for motorized components, effectively separating gas from liquid using centrifugal force and vortex induction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a driven shaft is used in downhole gas separators, then gas separation can be achieved through centrifugal force, but the device complexity increases and the system becomes inapplicable to certain well configurations

Engineering Contradiction:
Improvegas separation effectivenessVSAvoidpresence of driven shaft
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the driven shaft from the gas separator system entirely. Instead of using a motorized agitator with a driven shaft, the invention employs a passive separator that utilizes the natural flow of wellbore fluid through a specially designed chamber with a screened outlet. This extraction of the driven shaft eliminates mechanical complexity while maintaining gas separation functionality through fluid dynamics and gravity-based phase separation.

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If motorized components are used for gas separation, then separation efficiency improves, but the device becomes inapplicable to wells without external power sources

Engineering Contradiction:
Improvegas separation efficiencyVSAvoidapplicability to different well configurations
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The passive multiphase separator operates autonomously without requiring external power sources or motorized components. The separator utilizes the natural kinetic energy and flow characteristics of the wellbore fluid to achieve phase separation. The fluid enters the separator chamber, and through the combination of flow velocity, chamber geometry, and gravity, gas and liquid phases separate naturally. The screened outlet allows gas to pass through while liquid accumulates and exits separately, all without mechanical agitation or powered components.

Inventive Principle:
Principle #25Self-service

3Reliability

If centrifugal force is applied through rotating agitators, then gas-liquid separation is enhanced, but the system complexity and maintenance requirements increase

Engineering Contradiction:
Improvephase separation capabilityVSAvoidrotating agitator mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical rotating agitator system with a passive fluid dynamic system. Instead of using a motor-driven agitator that rotates to create centrifugal force, the invention relies on the natural flow velocity and pressure differential of the wellbore fluid to create the necessary forces for phase separation. The separator chamber geometry and screened outlet work together to separate gas and liquid phases without any moving mechanical parts, thereby eliminating maintenance requirements associated with rotating components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 passive multiphase separator efficiently separates gas from liquid in the wellbore, reducing the burden on surface separators and preventing gas-related issues in downhole equipment, while being applicable across a range of applications without requiring external power or moving parts.

Implementation Method 1

The interior section includes a rifled interior surface

Methodology Applied
Scientific EffectVortex induction: Vortex Ring

Implementation Method 2

The passive multiphase separator efficiently separates gas from liquid in the wellbore using centrifugal force and vortex induction

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3619398B1Passive multiphase flow separator
Publication Date: 2022.10.26 BAKER HUGHES ESP INC
  • EP3619398B1 patent drawingFigure 1
  • EP3619398B1 patent drawingFigure 2~4
  • EP3619398B1 patent drawingFigure 5

AI summary

A passive multiphase separator is configured to separate gas from a two-phase fluid in a wellbore. The passive multiphase separator includes an intake tube that has an intake end, a discharge end and an interior section between the intake end and the discharge end. The interior section includes a rifled interior surface that induces rotation in fluids passing through the interior section. The passive multiphase separator further includes a head assembly connected to the discharge end of the intake tube. The head assembly includes a crossover tube extending into the interior section, one or more gas vents extending from an interior of the crossover tube to an exterior of the head assembly and a liquid discharge. The passive multiphase separator can be deployed in a variety of hydrocarbon recovery systems.