Piezoelectric Coated Proppants for Downhole Tracking
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Solution Overview
Problem
Current methods are inadequate for effectively tracking and monitoring proppants in a downhole environment, as a significant portion of proppants flow back to the wellbore, and there is limited ability to assess their location and fracture geometry over time.
Innovation Solution
Composite proppant compositions with coatings that change electromagnetic properties under mechanical stress, such as closure stress, allowing for detection and tracking using techniques like microseismic monitoring, with materials like piezoelectric or magnetostrictive coatings applied to particulate substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional proppants are used without special coatings, then the proppant pack provides mechanical support to keep the fracture open, but the proppants cannot be tracked or monitored in the downhole environment
Solution Approach 1:
The patent applies composite materials by coating conventional proppant particles with piezoelectric or magnetostrictive materials. This creates a composite structure where the core proppant provides mechanical support while the coating layer enables electromagnetic tracking. The composite approach allows both functions (mechanical support and tracking) to coexist without fundamentally changing the proppant system.
Solution Approach 2:
The tracking functionality is applied locally through coatings rather than requiring the entire proppant system to be fundamentally different. Only a portion of the proppant (the coating layer) needs to possess special electromagnetic properties, while the bulk proppant material maintains its mechanical support function. This local application reduces overall system complexity.
2Loss of information
If a substantial portion of proppant flows back to the wellbore, then proppant placement is incomplete, but there is limited ability to assess the extent of flowback or track proppant locations over time
Solution Approach 1:
The patent implements feedback by enabling continuous monitoring of proppant locations through electromagnetic detection of piezoelectric or magnetostrictive coatings. This provides real-time information about proppant distribution and flowback extent, allowing operators to assess placement effectiveness and make informed decisions about additional treatments needed.
3Measurement precision
If piezoelectric or magnetostrictive coatings are applied to proppants, then proppant tracking becomes possible, but the manufacturing process becomes more complex
Solution Approach 1:
The patent uses thin coating layers of piezoelectric or magnetostrictive materials that require minimal material quantities. These coatings can be applied as thin films rather than requiring thick layers or complete replacement of proppant material, reducing manufacturing complexity and material costs.
4Measurement precision
If 100% of proppant is made detectable with piezoelectric or magnetostrictive coatings, then complete tracking coverage is achieved, but the cost increases significantly
Solution Approach 1:
The patent enables a small subset of proppant particles to serve multiple functions: maintaining mechanical support while providing electromagnetic tracking signals. This allows conventional proppant blends to be enhanced with a minimal amount of specially coated particles, achieving effective tracking without requiring all proppant to be expensive specialized material.
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
Enables accurate tracking and monitoring of proppant locations, providing valuable information on fracture geometry and reducing flowback, while offering economic advantages through the use of blends with detectable signals in less expensive proppant mixes.
Implementation Method 1
coatings by materials whose electromagnetic properties change under a mechanical stress such as the closure stress of a fracture
Implementation Method 2
coatings by materials whose electromagnetic properties change under a mechanical stress such as the closure stress of a fracture
Data Source
AI summary
A method for “tagging” proppants so that they can be tracked and monitored in a downhole environment, based on the use of composite proppant compositions comprising a particulate substrate coated by a material whose electromagnetic properties change at a detectable level under a mechanical stress such as the closure stress of a fracture. In another aspect, the invention relates to composite proppant compositions comprising coatings whose electromagnetic properties change under a mechanical stress such as the closure stress of a fracture. The substantially spherical composite proppants may comprise a thermoset nanocomposite particulate substrate where the matrix material comprises a terpolymer of styrene, ethylvinylbenzene and divinylbenzene, and carbon black particles possessing a length that is less than 0.5 microns in at least one principal axis direction incorporated as a nanofiller; upon which particulate substrate is placed a coating comprising a PZT alloy manifesting a strong piezoelectric effect or Terfenol-D manifesting giant magnetostrictive behavior to provide the ability to track in a downhole environment.