Stabilizing Biphasic Polyelectrolyte Concentrates

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Solution Overview

Problem

Current methods for preparing well treatment fluids face challenges such as slow hydration processes, equipment costs, and instability of polymer solutions, particularly with guar polymers, which hinder efficient viscosity achievement and storage stability.

Innovation Solution

A method involving a water-in-water emulsion system with a rheological polymer, a partitioning agent, and a charged polyelectrolyte is used to create a stabilized heterogeneous mixture, allowing for rapid hydration and improved storage stability by forming a dispersed rheological polymer-rich phase and a partitioning agent-rich phase, which can be easily injected into a well bore.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If guar polymer is used to increase viscosity, then fluid viscosity is improved, but phase separation occurs leading to instability

Engineering Contradiction:

Improvefluid viscosityVSAvoidphase separation

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

A charged polyelectrolyte is introduced as an intermediary substance that mediates between the guar polymer and water. The polyelectrolyte forms complexes with the guar polymer, preventing phase separation while maintaining the viscosity-enhancing properties of the guar. This intermediary approach allows the system to achieve both high viscosity and stability simultaneously.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the electrical charge parameter of the polymer system by introducing a charged polyelectrolyte. This parameter change transforms the interaction between guar polymer chains and water, preventing the hydrophobic effects that cause phase separation. The charged state of the polyelectrolyte modifies the overall electrostatic environment, stabilizing the polymer-solvent mixture.

Inventive Principle:

Principle #35Parameter changes

2Strength

If polymer concentration is increased to achieve desired viscosity, then viscosity is improved, but hydration time increases

Engineering Contradiction:

Improvefluid viscosityVSAvoidhydration time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The charged polyelectrolyte is pre-mixed with the guar polymer before introduction into the wellbore fluid. This preliminary action ensures that the polymer is already stabilized against phase separation, allowing for rapid hydration and viscosity development without requiring extended waiting periods. The pre-complexed structure facilitates faster water uptake and network formation.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If polymer is delivered as concentrated slurry, then equipment complexity is reduced, but phase segregation occurs during storage

Engineering Contradiction:

Improveequipment needsVSAvoidphase segregation

Core Design Contradiction:

Device complexityVSStability of the object's composition

Solution Approach 1:

The charged polyelectrolyte serves as a stabilizing intermediary that prevents phase segregation in the concentrated polymer slurry during storage and transport. By forming a stable complex with the guar polymer, the polyelectrolyte maintains uniform distribution of polymer chains throughout the slurry, preventing the formation of separate polymer-rich and water-rich phases that would occur in conventional concentrated slurries.

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

This approach enables the rapid formation of well treatment fluids with enhanced hydration efficiency and stability, reducing equipment needs and minimizing phase segregation, thus improving the overall effectiveness and efficiency of well treatment processes.

Implementation Method 1

stabilizing biphasic concentrates through the addition of small amounts of high molecular weight polyelectrolytes

Methodology Applied

Scientific EffectElectrostatic stabilization: Electrostatics

Implementation Method 2

forming a stabilized heterogeneous mixture comprising a dispersed rheological polymer-rich phase and a partitioning agent-rich phase

Methodology Applied

Scientific EffectPhase separation:

Data Source

PatentUS8043999B2Stabilizing biphasic concentrates through the addition of small amounts of high molecular weight polyelectrolytes

Publication Date: 2011.10.25 SCHLUMBERGER TECH CORP

AI summary

This invention relates to compositions and methods of treating a subterranean formation penetrated by a well bore including providing a treatment composition comprising a rheological polymer, a partitioning agent, a charged polyelectrolyte, and a first liquid medium, forming a stabilized heterogeneous mixture comprising a dispersed rheological polymer-rich phase and a partitioning agent-rich phase, and injecting the treatment fluid into the well bore. The invention relates to methods and compositions for preparing a well treatment fluid, including mixing polyethylene glycol partitioning agent, a charged polyelectrolyte, a first aqueous medium, and one or more rheological polymers selected from the group consisting of guar, modified guar, cellulose, modified cellulose, heteropolysaccharide, heteropolysaccharide derivative, or polyacrylamide, to hydrate the one or more polymers and form a water-in-water emulsion, and mixing the water-in-water emulsion with a second aqueous medium to form a well treatment fluid.