Complexation Particles for VES Fluid Stability

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Solution Overview

Problem

Viscoelastic surfactants (VES) in aqueous treating fluids used for hydraulic fracturing are degraded by metal ions, leading to unpredictable viscosity changes and formation damage, as these ions cause redox reactions that alter the VES gel structure uncontrollably.

Innovation Solution

Adding an effective amount of complexation particles to the aqueous treating fluid to complex metal ions, preventing them from reacting with VES and maintaining viscosity, with complexation particles ranging from 0.0001 wt % to 0.5 wt % and sizes from 1 nm to 50 microns, including high cation exchange capacity phyllosilicate mineral particles and alkaline earth metal oxides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If VES is used as a gelling agent in aqueous treating fluid, then the fluid achieves stable viscosity and improved proppant suspension, but the VES is degraded by metal ions causing unpredictable viscosity changes

Engineering Contradiction:

ImproveVES gel stabilityVSAvoidviscosity stability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

Complexation particles are introduced as intermediary substances that bind to metal ions, preventing direct interaction between metal ions and VES molecules. This mediator approach removes the harmful catalytic effect of metal ions on VES degradation while preserving the beneficial gelation properties of VES.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful metal ions are extracted from the aqueous treating fluid through complexation with specialized particles. By removing or sequestering the metal ions that cause degradation, the system eliminates the source of viscosity instability while maintaining the functional integrity of the VES gel.

Inventive Principle:

Principle #2Taking out (Extraction)

2Stability of the object's composition

If polymer gelling agents are used to increase fluid viscosity, then proppant suspension is improved, but filter cake and coating are left on formation face and proppant

Engineering Contradiction:

Improvefluid viscosityVSAvoidfilter cake and coating

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent transitions from using traditional polymer gelling agents to viscoelastic surfactants (VES) that operate through different rheological mechanisms. This parameter change in the gelling mechanism allows achieving high viscosity without the harmful side effects of filter cake formation and proppant coating, as VES provides viscosity through molecular structure rather than polymer deposition.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If metal ions are present in aqueous base fluid, then fluid preparation is simplified, but VES degradation occurs through redox reactions

Engineering Contradiction:

Improvefluid preparationVSAvoidVES degradation

Core Design Contradiction:

Ease of manufactureVSLoss of substance

Solution Approach 1:

Complexation particles serve as intermediaries that bind to metal ions in the aqueous base fluid, preventing redox reactions between metal ions and VES molecules. This allows the use of standard aqueous base fluids containing metal ions without suffering VES degradation, maintaining both ease of manufacture and chemical stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 method effectively inhibits VES degradation by metal ions, maintaining viscosity and preventing formation damage, allowing for controlled breaking characteristics and improved clean-up of fracturing fluids, enhancing hydrocarbon productivity.

Implementation Method 1

adding an effective amount of complexation particles to an aqueous treating fluid to complex any metal ions present therein

Methodology Applied

Scientific EffectComplexation:

Implementation Method 2

these ions cause redox reactions that alter the VES gel structure uncontrollably

Methodology Applied

Scientific EffectRedox reactions: Redox Reactions

Implementation Method 3

The method effectively inhibits VES degradation by metal ions, maintaining viscosity

Methodology Applied

Scientific EffectInhibition of degradation:

Data Source

PatentUS9169431B2Method to complex metals in aqueous treating fluids for VES-gelled fluids

Publication Date: 2015.10.27 BAKER HUGHES CO

AI summary

Aqueous treating fluids may include a viscoelastic surfactant (VES) and an aqueous base fluid, e.g. a drilling fluid, whereby the VES may increase and/or maintain the viscosity of the aqueous treating fluid. Metal ions may be present within the aqueous treating fluid that break, reduce, and/or digest the VES within the aqueous treating fluid. An effective amount of complexation particles may be added to the aqueous treating fluid for complexing at least a portion of these metal ions and thereby disallowing the metal ions from breaking, reducing, and/or altering the VES within the aqueous treating fluid.