Coated Proppants for Fracking: Polymer Elasticity and Compressive Strength
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Solution Overview
Problem
Current proppants used in fracking are brittle and lack sufficient compressive strength, leading to breakage under high pressure, which releases fine particles that clog cracks and reduce oil or gas production rates.
Innovation Solution
Coated proppants with an inorganic carrier material and a polymer coating derived from ethylenically unsaturated monomers, such as vinyl esters, methacrylic esters, and silane groups, which are produced through radically initiated polymerization in an aqueous medium, providing enhanced elasticity and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If proppants are used to keep cracks open in fracking, then permeability of deposit rocks is increased, but the proppants break under high pressure and release fine particles that block cracks and reduce production rates
Solution Approach 1:
The patent applies composite materials by combining an inorganic carrier material (sand or silica gel) with an organic polymer coating. This composite structure provides both the hardness of the inorganic core and the elasticity of the organic coating, allowing the proppant to withstand high compressive pressures without breaking while maintaining crack openness.
Solution Approach 2:
The patent uses a flexible polymer coating shell around the inorganic carrier. This thin film layer provides elasticity and deformability, allowing the proppant to flex under high pressure rather than fracture, thereby preventing the release of fine particles that would block cracks.
2Stability of the object's composition
If coated proppants with organic resin coatings are used to improve stability, then coating stability is enhanced, but the coatings are very brittle and have a tendency to break or flake off
Solution Approach 1:
The patent changes the physical and chemical parameters of the coating material by selecting polymers with specific glass transition temperatures (Tg between -50°C and +50°C) and controlled elasticity moduli. This parameter optimization ensures the coating remains stable yet flexible under fracking conditions, preventing both breakdown and flaking.
Solution Approach 2:
The patent applies different properties to different parts of the proppant structure: the inorganic carrier provides local hardness and structural integrity, while the organic coating provides local elasticity and flexibility. This local differentiation of material properties allows the composite proppant to resist both compression and coating failure.
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 elasticity and deformability, reducing the tendency to break and releasing fewer fine fractions, thus maintaining flow rates and reducing clogging, leading to economic and environmental benefits.
Implementation Method 1
polymers which are obtained by radically initiated polymerization in aqueous medium
Data Source
AI summary
The invention relates to coated support means for fracking mining methods, containing an inorganic substrate material and a coating containing polymers of one or more ethylenically unsaturated monomers from the group containing vinyl esters of unbranched or branched alkyl carboxylic acids with 1 to 15 C atoms, methacrylic acid esters and acrylic acid esters of alcohols with 1 to 15 C atoms, vinyl aromatics, olefins, dienes and vinyl halides, characterised in that the polymers are obtained by means of radical-initiated polymerisation in an aqueous medium, wherein 0.5 to 20 wt. % of ethylenically unsaturated and silane group-containing monomers are copolymerised, in relation to the total weight of the monomers.