Coated Proppants for Hydraulic Fracturing
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Solution Overview
Problem
Conventional proppants, such as sand and ceramic materials, lack sufficient crush resistance and durability in high-pressure hydraulic fracturing processes, leading to breakdown and fines migration, which restricts flow conductivity in subsurface formations.
Innovation Solution
A coated proppant design featuring a surface copolymer layer crosslinked by divinyl benzene and a resin layer, which enhances mechanical strength, crush resistance, and chemical resistance, preventing fines migration and flowback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional proppants (sand, ceramic) are used in high-pressure hydraulic fracturing, then the fractures can be held open, but the proppant breaks down due to insufficient crush resistance
Solution Approach 1:
The patent applies composite materials by coating proppant particles with a polymer coating layer comprising a polyolefin matrix and a polyacrylonitrile phase. This composite structure combines the mechanical strength of the proppant core with the protective and strengthening properties of the polymer coating, increasing crush resistance and preventing breakdown in high-pressure environments.
Solution Approach 2:
The patent changes the physical and chemical parameters of the proppant surface by applying a polymer coating. This coating modifies the surface properties to enhance mechanical strength, chemical resistance, and thermal stability, thereby improving overall proppant performance in high-pressure hydraulic fracturing operations.
2Object-affected harmful factors
If ceramic proppants are used, then chemical resistance is improved, but they break down in wet conditions due to loss of crush resistance
Solution Approach 1:
The patent changes the physical and chemical parameters of the proppant surface by applying a polymer coating. This coating modifies the surface properties to enhance mechanical strength, chemical resistance, and thermal stability, thereby improving overall proppant performance in high-pressure hydraulic fracturing operations.
3Ease of manufacture
If proppant particles are used without coating, then manufacturing is simpler, but they generate fines that migrate into the formation and restrict flow conductivity
Solution Approach 1:
The patent uses a flexible polymer coating layer as a protective shell around the proppant particles. This thin film structure prevents the proppant core from breaking down and generating fines, while allowing the coating itself to remain flexible and adaptable to the proppant shape. The coating acts as a barrier that contains the proppant integrity, preventing fines migration into the formation.
4Strength
If a polymer coating is applied to increase surface area and distribute crush stress, then crush percentage decreases, but the coating itself may degrade at downhole temperatures
Solution Approach 1:
The patent applies composite materials by coating proppant particles with a polymer coating layer comprising a polyolefin matrix and a polyacrylonitrile phase. This composite structure combines the mechanical strength of the proppant core with the protective and strengthening properties of the polymer coating, increasing crush resistance and preventing breakdown in high-pressure environments.
Solution Approach 2:
The patent changes the physical and chemical parameters of the proppant surface by applying a polymer coating. This coating modifies the surface properties to enhance mechanical strength, chemical resistance, and thermal stability, thereby improving overall proppant performance in high-pressure hydraulic fracturing operations.
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 coated proppants exhibit improved mechanical stability, reduced fine production, and increased durability, enabling effective use in high-pressure hydraulic fracturing operations while maintaining flow conductivity.
Implementation Method 1
a copolymer of at least two monomers chosen from styrene, methyl methacrylate, ethylene, propylene, butylene, imides, urethanes, sulfones, carbonates, and acrylamides, where the copolymer is crosslinked by divinyl benzene
Implementation Method 2
a resin layer surrounding the surface copolymer layer, the resin layer comprising a cured resin
Data Source
AI summary
Coated proppants include a proppant particle, a surface copolymer layer surrounding the proppant particle, and a resin layer surrounding the surface copolymer layer. The surface copolymer layer includes a copolymer of at least two monomers chosen from styrene, methyl methacrylate, ethylene, propylene, butylene, imides, urethanes, sulfones, carbonates, and acrylamides, where the copolymer is crosslinked by divinyl benzene. The resin layer includes a cured resin. Methods of preparing the coated proppants include preparing a first mixture including at least one polymerizable material, an initiator, and a crosslinker including divinyl benzene; contacting the first mixture to a proppant particle to form a polymerization mixture; heating the polymerization mixture to cure the polymerizable material and form a polymer-coated particulate; preparing a second mixture including the polymer-coated substrate, an uncured resin, and a solvent; and adding a curing agent to the second mixture to cure the uncured resin and form the coated proppant.