Quaternary Ammonium Coating for Proppant Fracture Conductivity

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Solution Overview

Problem

Traditional methods for enhancing fracture conductivity in subterranean formations often result in reduced fluid flow due to proppant consolidation, incomplete fluid removal, and water saturation, leading to decreased well productivity.

Innovation Solution

The use of quaternary ammonium ionic liquids to coat proppant particulates, creating a surface with minimal interaction with hydrocarbons and water, which improves fluid flow and reduces water saturation, thereby enhancing fracture conductivity and well productivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If proppant particulates are consolidated within fractures to prevent proppant flow back, then proppant stability is improved, but fracture conductivity deteriorates due to reduced fluid flow

Engineering Contradiction:
Improveproppant stabilityVSAvoidfracture conductivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

A resin coating is applied to proppant particulates as an intermediary layer that prevents direct consolidation while maintaining structural stability. The resin acts as a mediator between the proppant particles and the fracture environment, allowing fluid flow through its porous structure while preventing particle-to-particle contact that would cause consolidation and reduce conductivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If hydraulic fracturing fluid is injected to create and prop fractures, then fracture formation is achieved, but fluid removal becomes incomplete leaving water saturation that reduces hydrocarbon flow

Engineering Contradiction:
Improvefracture formationVSAvoidwater saturation
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The resin coating changes the surface properties and wettability parameters of proppant particulates, creating a hydrophobic barrier that prevents water adherence. This parameter change in surface chemistry allows for more complete fluid removal while maintaining the fracture structure, reducing residual water saturation that would otherwise block hydrocarbon flow.

Inventive Principle:
Principle #35Parameter changes

3Strength

If proppant particulates are placed in fracture to maintain propped condition, then fracture support is improved, but porosity reduces due to particle consolidation

Engineering Contradiction:
Improvefracture supportVSAvoidfracture porosity
Core Design Contradiction:
StrengthVSVolume of stationary object

Solution Approach 1:

The resin coating creates a porous structure around proppant particulates that maintains inter-particle void space. This porous material approach preserves fracture porosity by preventing complete particle consolidation while still providing mechanical support, allowing hydrocarbon fluids to flow through the porous resin matrix between proppant particles.

Inventive Principle:
Principle #31Porous 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 quaternary ammonium ionic liquid coating increases the flow rate of both water and hydrocarbons through the proppant pack, reducing water saturation and improving well productivity by maintaining high porosity and conductivity of the fracture.

Implementation Method 1

coating the proppant particulates with an ionic liquid such as quaternary ammonium salt... creating a surface with minimal interaction with hydrocarbons and water

Methodology Applied
Scientific EffectHydrophobic effect: Hydrophobe

Implementation Method 2

The flow back aids reduce damage due to phase trapping, improve mobilization of the oil and gas, increase the regained permeability and enhance the oil/gas recovery

Methodology Applied
Scientific EffectCapillary pressure reduction: Capillary Pressure

Data Source

PatentUS10815421B2Flow back aids
Publication Date: 2020.10.27 ETHOX CHEM LLC

AI summary

The present invention discloses liquid quaternary ammonium salts that can be used to treat and coat the surfaces of the proppant sand or inorganic particles that are used in down-hole oil well fracturing operations as well as the containment structure and that these treated surfaces will cause water and oils to flow faster through the porous structure. These liquid quaternary ammonium salts can be chosen from a list that includes but is not limited to cocobis(2-hydroxyethyl)ethylammonium ethyl sulfate, benzylcocobis(hydroxyethyl)ammonium 2-ethylhexylsulfate, dibenzylcocobishydroxyethyl ammonium phenolsulfonate, didecyldimethyl-ammonium dodecylbenzenesulfonate and tallow-bis(2-hydroxyethyl)ethylammonium ethyl sulfate.