Viscoelastic Surfactant Fluid with Modified Nanoparticles for Hydraulic Fracturing

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Solution Overview

Problem

Viscoelastic surfactant (VES) fluids used in hydraulic fracturing face challenges such as poor stability at high temperatures and in complex brine conditions, and lack of viscosity-elasticity control when combined with other chemical components, which affect the performance of proppant transport and permeability retention in oilfield applications.

Innovation Solution

A viscoelastic surfactant fluid composition comprising a surfactant, a counterion, and a modified nanoparticle, such as silica, clay, or graphene nanoparticles, which enhances stability and viscosity control, allowing for efficient proppant transport and improved permeability retention by forming higher-order micelles and reducing fluid loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If VES fluids are used as hydraulic fracturing fluids, then proppant transport efficiency is improved and fracture height growth is minimized, but stability at high temperatures and in complex brine conditions deteriorates

Engineering Contradiction:

Improveproppant transport efficiencyVSAvoidstability at high temperatures and in complex brine conditions

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces a breaker system as an intermediary component that controls the timing of VES fluid breakdown. The breaker remains dormant during pumping and proppant transport, then activates in the fracture to break down the VES fluid, allowing it to provide viscosity during transport while maintaining stability during these critical phases. This resolves the contradiction by using the breaker as a temporal mediator.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent formulates the VES fluid with specific surfactant concentrations and compositions (0.5-5% VES) that provide adequate viscosity and proppant transport capability from the outset, eliminating the need for high concentrations that would compromise thermal and brine stability. The preliminary formulation optimizes the balance between transport efficiency and stability.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If VES is used as a polymer-free viscosifying medium, then fluid recovery is improved and breaker requirement is reduced, but viscosity-elasticity control deteriorates when combined with other chemical components

Engineering Contradiction:

Improvefluid recoveryVSAvoidviscosity-elasticity control

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The patent systematically adjusts key parameters including surfactant concentration (0.5-5%), counterion concentration (0.1-1%), and nanoparticle concentration (0.01-1%) to optimize the balance between fluid recovery ease and viscosity-elasticity control. By controlling these parameters within specific ranges, the formulation achieves both easy recovery and operational control.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite VES fluid system combining surfactant, counterion, and nanoparticle components that work synergistically. This composite approach provides enhanced viscosity-elasticity control while maintaining the polymer-free advantage for easy recovery. The composite formulation addresses the control issue without sacrificing recovery ease.

Inventive Principle:

Principle #40Composite materials

3Reliability

If crosslinked gels are used for viscosifying, then leak-off control is improved, but retained permeability of proppant pack deteriorates

Engineering Contradiction:

Improveleak-off controlVSAvoidretained permeability of proppant pack

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent employs VES fluid as a temporary, disposable viscosifying medium that provides adequate leak-off control during the fracturing operation, then breaks down completely after serving its purpose. Unlike crosslinked gels that leave residual polymer affecting permeability, the VES fluid degrades to simple surfactant molecules and salts that do not harm the proppant pack, achieving both leak-off control and permeability preservation.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 modified viscoelastic surfactant fluid composition demonstrates enhanced stability and viscosity across a wide temperature range, improved permeability retention, and reduced fluid loss, enabling more effective hydraulic fracturing and oil recovery by maintaining proppant pack conductivity and fracture geometry.

Implementation Method 1

Viscosity of a VES fluid is created by self-assembly of surfactant molecules in an aqueous solution or emulsion. Surfactants associate and orient to create spherical, rod-shaped and bicontinuous structures of lyotropic liquid crystalline order.

Methodology Applied

Scientific EffectSelf-assembly: Self-Assembly

Implementation Method 2

Surfactants associate and orient to create spherical, rod-shaped and bicontinuous structures of lyotropic liquid crystalline order.

Methodology Applied

Scientific EffectLyotropic liquid crystalline order: Liquid Crystals

Implementation Method 3

A viscoelastic surfactant fluid composition containing: a surfactant; a counterion; and a modified nanoparticle.

Methodology Applied

Scientific EffectSurface modification: Coatings

Data Source

PatentUS12018209B2Viscoelastic surfactant fluid composition, and method of using the same

Publication Date: 2024.06.25 MITSUBISHI GAS CHEM CO INC

AI summary

A viscoelastic surfactant fluid composition comprising: a surfactant: a counterion: and a modified nanoparticle.