Viscoelastic Surfactant Fluids with Modified Nanocellulose for High-Temperature Stability

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Solution Overview

Problem

Existing Viscoelastic Surfactant (VES) formulations for oil and gas well stimulation and completion face challenges such as poor stability at high concentrations and temperatures, instability in complex brine conditions, lack of viscosity-elastic control, and high cost.

Innovation Solution

A new VES formulation is developed, combining a viscoelastic surfactant with modified nanomaterials, such as nanocellulose, to enhance stability, viscosity control, and cost-effectiveness. This composition includes surface-modified nanomaterials and polymers to improve stability and performance under various conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If VES concentration is increased to achieve desired viscosity, then viscosity is improved, but stability deteriorates due to poor stability at high concentrations and temperatures

Engineering Contradiction:

ImproveviscosityVSAvoidstability

Core Design Contradiction:

ForceVSStability of the object's composition

Solution Approach 1:

The patent combines viscoelastic surfactant (VES) with nanocellulose to form a composite fluid system. The nanocellulose acts as a stabilizing component that allows the VES to maintain high viscosity at elevated concentrations and temperatures without the stability issues inherent in pure VES systems. This composite approach enables the fluid to achieve the desired viscosity while maintaining compositional stability under downhole conditions.

Inventive Principle:

Principle #40Composite materials

2Force

If polymer viscosifiers are used to achieve viscosity, then viscosity is improved, but retained permeability deteriorates due to formation damage

Engineering Contradiction:

ImproveviscosityVSAvoidformation damage

Core Design Contradiction:

ForceVSObject-generated harmful factors

Solution Approach 1:

The patent employs nanocellulose as a biodegradable, environmentally benign viscosifier that replaces traditional polymer viscosifiers. The nanocellulose provides the necessary viscosity for the stimulation fluid but degrades naturally after use, avoiding the formation damage and residual polymer issues associated with conventional polymers like guar or polyacrylamide. This allows the fluid to perform its viscosity function temporarily without leaving harmful residues that would damage formation permeability.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Use of energy by moving object

If VES is used to reduce pumping energy, then energy consumption is improved, but cost increases due to higher VES concentration requirements

Engineering Contradiction:

Improvepumping energyVSAvoidcost

Core Design Contradiction:

Use of energy by moving objectVSQuantity of substance

Solution Approach 1:

The patent creates a composite system where nanocellulose enhances the efficiency of VES viscosity generation. The nanocellulose framework allows the VES to achieve high viscosity at lower concentrations than would be required in pure VES systems, thereby reducing the quantity of expensive VES needed while maintaining the low pumping energy advantage. This synergistic composite approach optimizes both energy efficiency and cost effectiveness.

Inventive Principle:

Principle #40Composite materials

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 new VES formulation demonstrates improved stability and self-diverting acid properties, maintaining high viscosity across a wide temperature range and varying brine conditions, thus enhancing the effectiveness of acid stimulation and completion operations while reducing costs.

Implementation Method 1

Viscosity of a VES fluid is created by self-assembly of surfactant small molecules in solution to create spherical, rod shaped and bicontinuous structures of lyotropic liquid crystalline order micelles

Methodology Applied

Scientific EffectSelf-assembly: Self-Assembly

Implementation Method 2

spherical, rod shaped and bicontinuous structures of lyotropic liquid crystalline order micelles

Methodology Applied

Scientific EffectLyotropic liquid crystalline order: Liquid Crystals

Implementation Method 3

Entanglement of these flexible and higher order micelles imparts increased viscosity to the solution

Methodology Applied

Scientific EffectEntanglement:

Implementation Method 4

improved stability at higher T and brine concentrations, and cost-effectiveness and performance

Methodology Applied

Scientific EffectThermal stability:

Implementation Method 5

self-diverting acid property

Methodology Applied

Scientific EffectStimuli-responsive behavior:

Data Source

PatentUS12234404B2Acid matrix applications: well stimulation and completion fluids using viscoelastic surfactants and modified additives

Publication Date: 2025.02.25 MITSUBISHI GAS CHEM CO INC

AI summary

A composition for an oil or gas well formation, containing a viscoelastic surfactant; and a modified nanomaterial and a producing method of the composition, and a forming method of the oil or gas well. The modified nanomaterial optionally contains a nanocellulose. The modified nanomaterial optionally has, on its surface, a sulfate group, a sulfite group, a carboxy group, an ethylene oxide chain, an amino group, an ester group, a silane group, a tertiary ammonium group or a mixture thereof.