Enzyme-Encapsulated Hydrogel Nanoparticles for Fracturing Fluid Cleanup

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Solution Overview

Problem

Current hydraulic fracturing methods face challenges with premature or incomplete breakdown of fracturing fluids, leading to inefficient fracture creation and incomplete cleanup, especially in unconventional reservoirs, resulting in low post-fracturing well productivity.

Innovation Solution

The use of enzyme-encapsulated hydrogel nanoparticles in hydraulic fracturing fluids delays the release of viscosifier-degrading enzymes, preventing premature degradation of polymers and ensuring effective proppant transport and placement, while allowing for controlled breakdown of fracturing fluids for fracture cleanup.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If enzyme is added to fracturing fluid to break down viscous fluids for cleanup, then fracture cleanup efficiency is improved, but premature degradation of polymers occurs leading to poor proppant transport

Engineering Contradiction:

Improvefracture cleanup efficiencyVSAvoidproppant transport capability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The enzyme is segmented from the fracturing fluid by encapsulating it within hydrogel nanoparticles. This physical separation allows the enzyme to be transported along with the fluid without immediately degrading the polymer viscosifier, thus maintaining proppant transport capability while enabling cleanup function. The encapsulation creates distinct phases: the enzyme-containing nanoparticles and the polymer-based fracturing fluid, which interact only when desired.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The enzyme is pre-loaded into hydrogel nanoparticles at high concentration before being introduced to the fracturing fluid. This preliminary encapsulation action prepares the enzyme in a controlled state that prevents premature activation. The nanoparticles are designed to maintain structural integrity during proppant transport, and only release the enzyme under specific conditions (such as pH change, temperature, or mechanical stress) after the fracturing operation is complete, ensuring cleanup occurs at the optimal time.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If high concentration of enzyme is used to ensure effective breakdown, then fracture cleanup is improved, but cost and fluid complexity increase

Engineering Contradiction:

Improvefracture cleanup efficiencyVSAvoidfluid composition complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Instead of adding large volumes of dilute enzyme solution to the fracturing fluid, the invention uses hydrogel nanoparticles that concentrate the enzyme activity into compact particles. Each nanoparticle acts as a micro-reservoir containing high enzyme concentration. This copying approach replicates the enzyme function in a condensed form that doesn't disrupt the overall fluid composition or require complex formulation adjustments, thereby maintaining simplicity while achieving effective cleanup.

Inventive Principle:

Principle #26Copying

3Productivity

If enzyme is released early to start cleanup sooner, then fracture cleanup is improved, but proppant carrying capability deteriorates

Engineering Contradiction:

Improvefracture cleanup efficiencyVSAvoidproppant placement quality

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The enzyme release system is designed to be dynamic rather than static. The hydrogel nanoparticles maintain structural stability during the high-shear, high-velocity conditions of proppant transport, preventing premature enzyme release. However, the nanoparticles are engineered to respond dynamically to post-fracturing conditions (such as pressure release, pH changes, or mechanical disruption in the fracture cavity), triggering enzyme release only when proppant placement is complete and cleanup is needed, thus adapting to different operational phases.

Inventive Principle:

Principle #15Dynamics

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 improves fracturing efficiency by maintaining proppant carrying capability and fracture conductivity, achieving effective fluid cleanup and reducing costs through high enzyme loading and low required concentrations, facilitating successful hydraulic fracturing in both conventional and unconventional reservoirs.

Implementation Method 1

hydrogel nanoparticles designed to delay release of an enzyme encapsulated therein

Methodology Applied

Scientific EffectEncapsulation: Physical Containment

Implementation Method 2

a plurality of hydrogel nanoparticles encapsulating a viscosifier-degrading enzyme

Methodology Applied

Scientific EffectHydrogel: Hydrogel

Implementation Method 3

viscosifier-degrading enzyme therein... breakdown of the fracturing fluids after the release of enzyme

Methodology Applied

Scientific EffectEnzyme degradation: Enzyme

Data Source

PatentUS11667831B2Enzyme-encapsulated hydrogel nanoparticles for hydraulic fracturing fluid cleanup

Publication Date: 2023.06.06 TEXAS A&M UNIVERSITY

AI summary

Provided herein is a hydraulic fracturing fluid containing enzyme encapsulated hydrogel nanoparticles and a breaker composition of a viscosifier-degrading enzyme encapsulated in the hydrogel nanoparticle. Also provided are methods for hydraulic fracturing utilizing hydrogel nanoparticles encapsulating an enzyme as a breaker to prevent the premature degradation of the fracturing fluid, to improve transport and placement of the proppant and to facilitate subsequent cleaning of the fracturing fluid.