Redox Cleanup Fluid for Fracture Viscosity Reduction

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Solution Overview

Problem

Traditional hydraulic fracturing methods leave behind residual viscous materials in fractures, reducing fracture conductivity and hindering hydrocarbon recovery due to incomplete cleanup.

Innovation Solution

A method involving a fracturing fluid with a viscous component and a proppant component, followed by a cleanup fluid containing triacetin and an exothermic reaction component, such as ammonium chloride and sodium nitrite, which generates heat to reduce the viscosity of residual materials, allowing them to flow out of the fractures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional viscosity breakers are used to breakdown the fracturing fluid, then the fluid structure is disrupted, but the fractures are not completely cleaned up and residual viscous material remains

Engineering Contradiction:
Improvefluid breakdownVSAvoidcleanup completeness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention changes the chemical parameters of the cleanup fluid by using a redox system (sodium hypochlorite and ammonium chloride) that generates heat and chemical reactions to fundamentally alter the viscous material, transforming it from a gel structure to a flowable state that can be completely removed from fractures

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The cleanup fluid employs a composite chemical system combining oxidizing agents (sodium hypochlorite), ammonium salts (ammonium chloride), and organic compounds (triacetin) that work synergistically to break down the viscous material through multiple mechanisms including oxidation, heat generation, and chemical reaction

Inventive Principle:
Principle #40Composite materials

2Strength

If highly viscous and gelled fluids are used in fracturing stages, then fracture creation and proppant placement are achieved, but residual viscous material blocks fractures and reduces conductivity

Engineering Contradiction:
Improvefracture creation capabilityVSAvoidfracture blockage
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The invention converts the harmful residual viscous material into a beneficial flowable substance by using the redox reaction to chemically transform the gel structure. The same viscous material that caused blockage is transformed into a low-viscosity fluid that enhances hydrocarbon flow and can be completely evacuated from the fractures

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The cleanup process induces a phase transition in the residual viscous material by using heat from the exothermic redox reaction to break the gel network structure, transforming the material from a high-viscosity gel phase to a low-viscosity fluid phase that can move freely through the fractures

Inventive Principle:
Principle #36Phase transitions

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 method effectively cleans up residual viscous materials, increasing fracture conductivity, improving hydrocarbon recovery, and reducing the need for additional fracturing operations by enhancing the flow of hydrocarbons.

Implementation Method 1

an exothermic reaction component operable to generate heat after the proppant component has been placed in the fractures... wherein the heat is operable to reduce a viscosity of the residual viscous material

Methodology Applied
Scientific EffectExothermic reaction: Exothermic Reaction

Implementation Method 2

the heat is operable to reduce a viscosity of the residual viscous material to create a reduced viscosity material, the reduced viscosity material operable to flow from the formation

Methodology Applied
Scientific EffectThermal energy reduction of viscosity: Heating

Data Source

PatentEP3132000B1Method for enhanced fracture cleanup using redox treatment
Publication Date: 2021.12.15 SAUDI ARABIAN OIL CO
  • EP3132000B1 patent drawingFigure 1
  • EP3132000B1 patent drawingFigure 2
  • EP3132000B1 patent drawingFigure 3a~3b

AI summary

A method for improved hydrocarbon recovery from a formation due to cleanup of a residual viscous material is provided. The method comprising the steps of fracturing the formation with a fracturing fluid to generate fractures, the fracturing fluid comprising a viscous fluid component operable to fracture the formation leaving behind residual viscous material in the fractures, the viscous fluid having a viscosity; a proppant component comprising a proppant, the proppant operable to hold open the fractures, wherein the proppant component is carried to the fractures by the viscous fluid component; and a cleanup fluid, the cleanup fluid comprising: an acid precursor operable to trigger an exothermic reaction component, and the exothermic reaction component operable to generate heat, where the generated heat is operable to reduce a viscosity of the residual viscous material to create a reduced viscosity material operable to flow from the formation.