Acrylic Acid Crosslinked Polymer for Hydraulic Fracturing Fluids

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Solution Overview

Problem

Conventional hydraulic fracturing methods using guar gum require additional toxic crosslinking agents and struggle with salt tolerance and heat resistance, limiting their effectiveness in deep underground applications.

Innovation Solution

A novel acrylic acid crosslinked polymer with high soluble content and a chelating agent is used to enhance thickening behavior and stability, reducing the need for toxic additives and improving salt tolerance and heat resistance in fracturing fluids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If guar gum is used as a fracturing fluid, then viscosity is improved, but toxic crosslinking agents are required and salt tolerance deteriorates

Engineering Contradiction:

ImproveviscosityVSAvoidtoxicity of crosslinking agents

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and eliminates the need for toxic crosslinking agents by using acrylic acid crosslinked polymer particles that inherently provide gelation functionality. The polymer particles themselves serve as both thickening agent and crosslinking mechanism, removing the separate toxic crosslinking step required in guar gum systems.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical composition parameters by replacing guar gum with acrylic acid crosslinked polymer. This parameter change provides both thickening effect and salt tolerance inherently, without requiring additional toxic crosslinking agents, thus resolving the contradiction between viscosity improvement and toxicity reduction.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If conventional water absorbent resin is used, then fluid retention capacity is improved, but thickening effect deteriorates

Engineering Contradiction:

Improvefluid retention capacityVSAvoidthickening effect

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The invention applies local quality by creating a dual-functional polymer particle system where the acrylic acid crosslinked polymer provides both fluid retention capacity (water absorbent resin function) and thickening effect (gelation function) within the same material structure, rather than requiring separate materials for each function.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The acrylic acid crosslinked polymer particles serve multiple functions simultaneously: they act as water absorbent resin for fluid retention, provide thickening effect through gelation, and offer salt tolerance. This multi-functionality resolves the contradiction by making a single material that performs both fluid retention and thickening that conventional water absorbent resins cannot achieve.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Length of moving object

If deep underground fracturing is performed, then extraction depth is improved, but heat resistance deteriorates

Engineering Contradiction:

Improvefracturing depthVSAvoidheat resistance

Core Design Contradiction:

Length of moving objectVSTemperature

Solution Approach 1:

The invention applies preliminary action by pre-crosslinking the acrylic acid polymer into stable crosslinked polymer particles before injection. This pre-formed crosslinked structure provides inherent thermal stability that allows the fracturing fluid to maintain its properties at high temperatures encountered in deep underground applications, resolving the heat resistance issue.

Inventive Principle:

Principle #10Preliminary action

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 acrylic acid crosslinked polymer achieves significant thickening effects, reduces chemical usage, and provides improved salt tolerance and heat resistance, enabling effective hydraulic fracturing in various geological conditions.

Implementation Method 1

use of a water absorbent resin for fracturing fluids has been proposed in recent years

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

coexistence with a chelating agent further improved the stability of viscosity

Methodology Applied

Scientific EffectChelation:

Data Source

PatentUS10696895B2Acrylic acid crosslinked polymer and use thereof

Publication Date: 2020.06.30 NIPPON SHOKUBAI CO LTD

AI summary

The present invention provides a novel acrylic acid crosslinked polymer and the use thereof. The present invention provides the acrylic acid crosslinked polymer in which the content of soluble components is 40 wt. % or higher. The present invention also provides a method for adjusting the viscosity of a fracturing fluid in a hydraulic fracturing method, the viscosity adjustment method including: A) a step of measuring the types and quantities of metal cations which are in water and which are the object of viscosity adjustment; B) a step of selecting the type and quantity of an acrylic acid crosslinked polymer on the basis of the types and quantities of metal cations and the pH so as to achieve a viscosity that is required for fracturing in a hydraulic fracturing method; and C) a step of adjusting the viscosity of the fracturing fluid using the acrylic acid crosslinked polymer of the selected type and quantity.