Surface Polymerized Proppants for High-Pressure Fracturing
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Solution Overview
Problem
Conventional proppants, such as fracking sands, have limited crush strength and are prone to crushing under high pressures, making them unsuitable for hydraulic fracturing processes exceeding 4000 psi.
Innovation Solution
Coated particles comprising a particulate substrate with a surface copolymer layer and a resin layer, where the surface copolymer layer is made from copolymers of styrene, methyl methacrylate, ethylene, and other monomers, and the resin layer is cured, enhancing the mechanical stability and roundness of the particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional proppants (fracking sands) are used, then the proppant is simple and inexpensive, but the crush strength is limited and the proppant crumbles under high pressures
Solution Approach 1:
The patent applies composite materials by coating particulate proppant substrates with multiple polymer layers including a surface copolymer layer (comprising styrene, methyl methacrylate, ethylene, propylene, butylene, imides, urethanes, sulfones, carbonates, or acrylamides) and a resin layer (comprising epoxy, polyester, polyurethane, or acrylic resin). This multi-layer composite structure significantly increases crush strength while maintaining the basic proppant particle form, resolving the contradiction between strength improvement and structural complexity.
Solution Approach 2:
The patent changes the physical and chemical parameters of the proppant surface through polymer coating. The coating process modifies surface properties, creates a protective barrier, and alters mechanical characteristics. The polymer layers change the stress distribution and load-bearing capacity parameters, enabling the proppant to withstand pressures exceeding 4000 psi without crumbling.
2Reliability
If the proppant is coated with polymer layers to increase crush strength, then the mechanical stability improves, but the manufacturing process becomes more complex
Solution Approach 1:
The patent segments the coating process into distinct sequential steps: (1) preparing the particulate substrate, (2) applying the surface copolymer layer through polymerization, (3) applying the resin layer, and (4) curing. This segmentation allows each layer to be optimized independently and facilitates controlled manufacturing, improving reliability while managing manufacturing complexity through systematic process division.
Solution Approach 2:
The patent employs preliminary action by preparing the particulate substrate beforehand (cleaning, drying, activating) before applying the polymer coatings. The substrate is pre-treated to ensure optimal adhesion and coating uniformity. This preliminary preparation simplifies subsequent coating steps and ensures consistent manufacturing results, thereby improving mechanical stability without proportionally increasing manufacturing complexity.
3Strength
If a multi-layer coating is applied to enhance proppant strength, then the proppant can withstand high pressures, but the production time increases
Solution Approach 1:
The patent implements continuity of useful action by applying multiple polymer layers in sequential, uninterrupted coating processes. The surface copolymer layer is applied first and cured, then the resin layer is applied and cured, with each step flowing continuously into the next. This continuous multi-step coating process efficiently builds up strength properties without excessive idle time, achieving high crush strength while controlling production time through streamlined sequential manufacturing.
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 particles exhibit increased crush strength and stability, enabling their use in high-pressure hydraulic fracturing operations by maintaining fracture openness and withstanding pressures commonly encountered in fracking fissures.
Implementation Method 1
heating the polymerization mixture to cure the polymerizable material and form a polymer-coated particulate including the particulate substrate and a surface copolymer layer surrounding the particulate substrate
Implementation Method 2
adding a curing agent to the second mixture to cure the uncured resin and form the coated particle
Data Source
AI summary
Coated particles include a particulate substrate, a surface copolymer layer surrounding the particulate substrate, 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. The resin layer includes a cured resin. Methods of preparing the coated particles include preparing a first mixture including at least one polymerizable material, an initiator, and optionally a solvent; contacting the first mixture to a particulate substrate 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 particle.