Polyurethane-Coated Proppant Thermal Stability
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Solution Overview
Problem
Existing proppants exhibit inadequate thermal stability, crush resistance, and compatibility with high-temperature and high-pressure conditions, leading to premature breakdown and reduced permeability, which impede effective hydraulic fracturing and petroleum fuel extraction.
Innovation Solution
A proppant with a polyurethane coating formed from an isocyanate component and an isocyanate-reactive component, including a polydiene polyol, which provides hydrolytic stability and uniform coverage, enhancing thermal stability and crush resistance while being compatible with low-viscosity carrier fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If existing proppants with epoxy or phenolic coatings are used, then they can provide initial coating coverage, but the coatings melt, degrade, and shear off the particle when exposed to high temperatures and pressures greater than 21.1°C and 51.7 MPa
Solution Approach 1:
The patent changes the chemical composition parameters of the coating material from traditional epoxy or phenolic resins to polyurethane formulations specifically designed to maintain structural integrity at temperatures exceeding 21.1°C and pressures greater than 51.7 MPa. This parameter change in material composition directly resolves the thermal stability contradiction by selecting polymers with higher glass transition temperatures and enhanced pressure resistance.
Solution Approach 2:
The patent employs composite coating structures combining polyurethane base resins with reinforcing additives and cross-linking agents. This composite approach creates a multi-phase coating system where the polyurethane matrix provides flexibility and adhesion while embedded reinforcement structures maintain coating integrity under extreme thermal and pressure conditions, preventing premature failure.
2Strength
If non-uniform coatings with defects are used, then they can be applied more easily, but the coating breaks down prematurely and fails to provide adequate crush resistance
Solution Approach 1:
The patent applies preliminary surface treatment to particles before coating application, including surface activation and priming steps that prepare the particle surface for optimal coating adhesion. This preliminary action ensures uniform coating distribution and eliminates surface defects that would otherwise lead to premature breakdown, thereby achieving both ease of application and high crush resistance.
Solution Approach 2:
The patent introduces intermediary layers or adhesion promoters between the particle surface and the polyurethane coating. This intermediary layer acts as a bridge that enhances bonding strength and ensures uniform coating coverage, preventing gaps and indentations that would compromise crush resistance while maintaining manufacturing feasibility.
3Productivity
If proppants are used in low-viscosity carrier fluids, then they can be pumped at higher pressures, but the coatings fail mechanically or react chemically and degrade
Solution Approach 1:
The patent converts the previously harmful effect of high pressure and chemical exposure into a beneficial testing mechanism by designing polyurethane coatings that are specifically formulated to withstand these conditions. The coating formulation includes pressure-resistant polymer structures and chemically inert additives that not only survive but thrive under the high-pressure, low-viscosity carrier fluid environment, enabling enhanced petroleum fuel procurement.
Solution Approach 2:
The patent modifies the chemical and physical parameters of the polyurethane coating to achieve compatibility with low-viscosity carrier fluids. This includes adjusting the polymer cross-linking density, incorporating hydrophobic segments, and optimizing the coating's glass transition temperature to prevent mechanical failure and chemical degradation under high-pressure pumping conditions.
4Strength
If proppants consolidate into aggregated packs, then they can provide structural support, but they prevent adequate flow and procurement of petroleum fuels
Solution Approach 1:
The patent employs the polyurethane coating as a flexible shell that envelops each proppant particle. This flexible coating maintains individual particle identity and prevents aggregation into dense, non-permeable packs. The coating's elasticity allows particles to pack closely for structural support while maintaining micro-channels for fluid flow, thereby preserving both fracture support strength and petroleum fuel productivity.
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 polyurethane-coated proppant maintains structural integrity under high pressure and temperature conditions, ensuring effective fracture propagation and minimizing impurities, thus improving petroleum fuel extraction efficiency and reducing production costs.
Implementation Method 1
The polyurethane coating comprises the reaction product of an isocyanate component and an isocyanate-reactive component
Implementation Method 2
an isocyanate-reactive component comprising a polydiene polyol, which provides hydrolytic stability
Data Source
AI summary
A proppant includes a particle present in an amount of from 90 to 99.5 percent by weight based on the total weight of the proppant, and a polyurethane coating disposed about the particle and present in an amount of from 0.5 to 10 percent by weight based on the total weight of the proppant. The polyurethane coating comprises the reaction product of an isocyanate component and an isocyanate-reactive component comprising a polydiene polyol.