Core-and-coating proppant for flowback control

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Solution Overview

Problem

Existing methods for proppant flowback control in hydraulic fracturing, such as resin-coated proppants and adhesive polymers, face issues with degradation, reduced fracture conductivity, and permeability loss, leading to costly cleanup operations and reduced well production rates.

Innovation Solution

Development of core-and-coating particulates with controllable hardness, comprising a deformable core and a polymer coating, which hardens under downhole conditions to prevent proppant flowback while maintaining fracture conductivity, achieved through temperature-induced cross-linking and chemical interactions with crude oil or gas condensate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If resin-coated proppant is used for flowback control, then proppant packing strength is improved, but fracture conductivity deteriorates due to secondary reactions degrading the resin coating

Engineering Contradiction:
Improveproppant packing strengthVSAvoidfracture conductivity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The proppant system is segmented into two functional components: deformable particles (1-10% by weight) that provide flowback control through stress redistribution, and conventional proppant (90-99% by weight) that maintains fracture conductivity. This segmentation allows each component to perform its specialized function without the negative interactions that occur in resin-coated systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The deformable particles act as intermediaries between the proppant packing and the fracturing fluid. These particles absorb and redistribute stresses, preventing direct harmful interactions between the fracturing fluid and the proppant packing, thereby maintaining both packing strength and fracture conductivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If adhesive polymer materials are used to coat proppant, then proppant flowback is controlled, but fracture permeability is reduced due to long-term tackiness

Engineering Contradiction:
Improveproppant flowback controlVSAvoidfracture permeability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The deformable particles are designed to perform their flowback control function temporarily during the critical early production period, then gradually degrade or redistribute stresses without leaving persistent adhesive residues. This temporary action protects fracture permeability long-term by avoiding the permanent blockage caused by long-term tacky coatings.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The physical and chemical parameters of the deformable particles change over time - they initially provide soft, stress-absorbing properties for flowback control, then gradually harden or degrade to restore fracture permeability. This dynamic parameter change allows the system to adapt to different production stages.

Inventive Principle:
Principle #35Parameter changes

3Strength

If thermoplastic material is mixed with proppant for flowback control, then proppant aggregates are formed, but production costs increase due to additional processing requirements

Engineering Contradiction:
Improveproppant aggregate strengthVSAvoidprocessing complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The deformable particles self-assemble into stress-distributing networks within the proppant packing without requiring external processing or activation. The particles naturally deform and interlock under downhole conditions, providing flowback control automatically without the need for thermoplastic mixing or additional processing steps.

Inventive Principle:
Principle #25Self-service

4Strength

If deformable particulate material is used for flowback control, then proppant packing strength is improved, but fracture permeability is reduced due to particle indentation

Engineering Contradiction:
Improveproppant packing strengthVSAvoidfracture permeability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The deformable particles exhibit local quality changes - they are soft and indentable at the particle level for stress absorption, but their collective arrangement in the proppant packing creates macro-scale pathways that maintain fracture permeability. This local-global property differentiation allows simultaneous achievement of packing strength and permeability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The proppant system is a composite material combining deformable particles (1-10% by weight) with conventional proppant (90-99% by weight). This composite structure leverages the stress-absorbing properties of the deformable component while maintaining the permeability-providing properties of the conventional proppant matrix.

Inventive Principle:
Principle #40Composite 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

Reduces proppant flowback and maintains fracture permeability, enhancing the strength and stability of the proppant packing, thereby increasing well production rates and reducing maintenance costs.

Implementation Method 1

achieved through temperature-induced cross-linking and chemical interactions with crude oil or gas condensate

Methodology Applied
Scientific EffectTemperature-induced cross-linking:

Implementation Method 2

achieved through temperature-induced cross-linking and chemical interactions with crude oil or gas condensate

Methodology Applied
Scientific EffectChemical interactions:

Data Source

PatentUS7718583B2Particulate material for proppant flowback control
Publication Date: 2010.05.18 SCHLUMBERGER TECH CORP

AI summary

Particulate material used for proppant flowback control from the fracture, where the material is a polymer which increases its hardness under downhole conditions.