Microwave-Sintered Ceramic Proppants for High-Pressure Hydraulic Fracturing
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Solution Overview
Problem
There is a need for solid ceramic particles with increased strength and crush resistance for use in hydraulic fracture stimulation of oil and gas wells, particularly at greater depths and under higher pressures, as existing proppants often lack sufficient durability to maintain permeability and conductivity over time.
Innovation Solution
The use of microwave-sintered, substantially round and spherical particles made from alumina-containing raw materials, which are processed to achieve specific properties such as bulk density, apparent specific gravity, and crush strength, enhancing their performance as proppants by improving their durability and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional proppants are used in hydraulic fracture stimulation, then the fracturing operation can be performed, but the proppants lack sufficient crush resistance and durability under high pressure at greater depths
Solution Approach 1:
The patent applies parameter changes by utilizing microwave energy to alter the physical and chemical properties of ceramic proppants during sintering. The microwave irradiation modifies the heating rate, temperature distribution, and microstructure development, resulting in enhanced crush resistance and durability. Specifically, the rapid and uniform heating from microwave energy creates a denser microstructure with fewer defects, directly improving the mechanical strength and pressure resistance of the proppants.
Solution Approach 2:
The patent replaces conventional mechanical or thermal sintering methods with microwave-based sintering. Instead of using traditional heating mechanisms (such as conductive or radiative heating from external sources), the invention uses electromagnetic microwave radiation to directly heat the proppant particles. This substitution enables more uniform and rapid heating, leading to improved densification and mechanical properties without the limitations of conventional thermal gradients.
2Reliability
If proppants are used to prop fractures, then permeability is maintained, but existing proppants lose conductivity over time due to insufficient crush resistance
Solution Approach 1:
The microwave sintering process changes key parameters including heating rate, temperature uniformity, and dwell time at peak temperature. These parameter changes result in a more homogeneous and dense microstructure within the proppant particles, reducing internal stresses and micro-cracks that would otherwise lead to particle breakdown. The enhanced microstructural integrity directly translates to maintained fluid conductivity over the long term under high-pressure conditions.
3Strength
If microwave sintering is used to produce ceramic particles, then crush strength and durability are improved, but the manufacturing process requires specialized equipment and control
Solution Approach 1:
The patent replaces complex multi-zone thermal control systems with a microwave-based heating system. Microwave sintering inherently provides more uniform and rapid heating throughout the proppant bed, reducing the need for complex temperature zoning and prolonged heating cycles. This substitution simplifies the overall process control while achieving superior densification and mechanical properties in shorter timeframes.
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 microwave-sintered proppants demonstrate improved crush strength and long-term fluid conductivity and permeability, even under high pressures, making them more effective in maintaining well permeability and facilitating economic oil and gas recovery.
Implementation Method 1
Described herein are methods for using microwave energy to fire and sinter proppants
Implementation Method 2
sintering the green pellets in a microwave furnace at a temperature of from about 1480° C. to about 1520° C. for a time at peak temperature of from about 20 to about 45 minutes
Data Source
AI summary
Methods for producing solid, substantially round, spherical and sintered particles from a slurry of a raw material having an alumina content of greater than about 40 weight percent. The slurry is processed to prepare green pellets which are sintered in a furnace with microwave energy at a temperature of 1480 to 1520° C. to produce solid, substantially round, spherical and sintered particles having an average particle size greater than about 200 microns, a bulk density of greater than about 1.35 g/cm3, and an apparent specific gravity of greater than about 2.60.