Dual-Cone Flow Stabilizer for Gas Well Liquid Loading

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Solution Overview

Problem

Gas wells face liquid loading issues due to declining reservoir pressure, leading to reduced production and necessitation of shut-in, as existing methods like velocity strings and artificial lift techniques are inefficient in maintaining stable gas-liquid flow.

Innovation Solution

A dual-cone flow stabilizing device is positioned within the production tubing to accelerate gas velocity and maintain a stable liquid film, preventing liquid film reversal and optimizing flow efficiency by modifying gas phase velocity and controlling pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a velocity string (smaller diameter tubing) is installed to increase gas velocity and lift liquid, then liquid loading is eliminated, but production rate decreases significantly

Engineering Contradiction:
Improveliquid lifting capabilityVSAvoidproduction rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The flow stabilizing device segments the flow cross-section into multiple regions (central region with higher velocity and annular region with lower velocity) using radial partitions. This allows different parts of the flow to have different velocities, maintaining overall high production rate while ensuring sufficient velocity in the central region to prevent liquid accumulation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The device creates local quality differences in the flow by generating a velocity profile where the central region has higher gas velocity than the annular region. This localized high velocity zone is sufficient to lift liquid and prevent loading, while the overall flow rate remains high due to the larger cross-sectional area utilized.

Inventive Principle:
Principle #3Local quality

2Productivity

If artificial lift techniques are used to re-energize fluid flow, then production can be maintained, but device complexity and operational cost increase

Engineering Contradiction:
Improveproduction maintenanceVSAvoidlift system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The flow stabilizing device utilizes the existing gas flow energy to automatically create the velocity profile needed for liquid lifting. The device passively redirects and accelerates the gas flow through its geometric structure without requiring external power sources, control systems, or additional energy input, thereby eliminating the need for complex artificial lift equipment.

Inventive Principle:
Principle #25Self-service

3Productivity

If standard production tubing is used, then production rate is high, but liquid loading occurs as reservoir pressure declines

Engineering Contradiction:
Improveproduction rateVSAvoidflow stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The flow stabilizing device dynamically adjusts the velocity distribution across the flow cross-section based on the existing flow conditions. As gas flows through the device, it automatically creates a velocity profile that adapts to varying flow rates, maintaining stable annular flow and preventing liquid loading across different production stages.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The device changes the flow parameters by transforming a relatively uniform velocity profile into a differentiated velocity profile with a high-velocity central core and lower-velocity annular region. This parameter transformation maintains the benefits of large diameter tubing while achieving the flow conditions necessary to prevent liquid loading.

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

The solution extends the life of gas wells by promoting a steady two-phase annular flow regime, increasing gas production and recovering condensate, with a 400% increase in gas production compared to traditional coiled tubing velocity strings.

Implementation Method 1

accelerate the velocity of the flowing two-phase fluid mixture in the tubing to sustain upward liquid flow

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

accelerate the velocity of the flowing two-phase fluid mixture in the tubing to sustain upward liquid flow

Methodology Applied
Scientific EffectGas lift: Gas Lift

Implementation Method 3

maintain a stable liquid film, preventing liquid film reversal

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 4

dual-cone flow stabilizing device is positioned within the production tubing to accelerate gas velocity

Methodology Applied
Scientific EffectVenturi effect: Venturi Effect

Data Source

PatentEP3529458B1Method and apparatus for stabilizing gas/liquid flow in a vertical conduit
Publication Date: 2022.01.26 SAUDI ARABIAN OIL CO
  • EP3529458B1 patent drawingFigure 1~2
  • EP3529458B1 patent drawingFigure 3A
  • EP3529458B1 patent drawingFigure 3B

AI summary

A method and apparatus for stabilizing gas/liquid flow in a vertical conduit by utilizing one or more flow stabilizing devices positioned inside the conduit along a structural support tube. The flow stabilizing devices are configured and dimensioned to accelerate the velocity of the flowing two-phase fluid mixture in the conduit to sustain upward liquid flow.