Crosslinked Polyethylene Proppant Density Suspension
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Solution Overview
Problem
Conventional proppants used in hydraulic fracturing have densities significantly higher than the fracturing fluid, leading to settlement and limited reach, necessitating the development of lower-density proppants with mechanical, thermal, and chemical stability for effective use in hydrocarbon wells.
Innovation Solution
Crosslinked polyethylene granules with characteristic dimensions between 100 micrometers and 2 millimeters, containing highly crosslinked polyethylene polymer chains and chemical crosslinks, are used as proppants to maintain suspension within the fracturing fluid and provide mechanical strength, thermal stability, and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional proppants (sand/ceramics) are used, then mechanical strength and thermal stability are achieved, but density is significantly higher than fracturing fluid causing settlement and limited reach
Solution Approach 1:
The patent changes the material composition from conventional sand/ceramics to crosslinked polyethylene, fundamentally altering the density parameter while maintaining proppant functionality. The crosslinking process modifies the polyethylene structure to achieve appropriate mechanical properties at lower density
Solution Approach 2:
The invention uses crosslinked polyethylene as a composite material that combines the benefits of polymer flexibility with crosslinked structural strength, creating a proppant that has both low density and adequate mechanical stability for fracture propping
2Stress or pressure
If lower-density proppants are used to increase reach and reduce settlement, then effective depth is improved, but mechanical strength and thermal stability deteriorate
Solution Approach 1:
The crosslinking process fundamentally changes the mechanical properties of polyethylene by creating a three-dimensional network structure. This transformation increases strength, rigidity, and thermal stability while maintaining the inherent low-density advantage of polyethylene material
Solution Approach 2:
The patent replaces the traditional mechanical interlocking strength of sand grains with chemical crosslinks in the polyethylene structure. The crosslinked network provides structural integrity through chemical bonds rather than relying solely on mechanical friction and interlocking
3Stress or pressure
If polyethylene is used as proppant to match density with fracturing fluid, then suspension and reach are improved, but mechanical strength and thermal stability are insufficient without crosslinking
Solution Approach 1:
The crosslinking process transforms polyethylene from a thermoplastic material with limited thermal and mechanical stability into a thermosetting-like structure that can withstand downhole conditions. The crosslinks prevent chain slippage and maintain structural integrity at elevated temperatures and stresses
Solution Approach 2:
The polyethylene is pre-crosslinked before being used as proppant, ensuring that the mechanical and thermal stability is established in advance. This preliminary crosslinking action prevents degradation during the high-temperature and high-stress conditions of fracturing and production
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 crosslinked polyethylene granules remain suspended within the fracturing fluid, ensuring effective propping of fractures at greater depths and maintaining permeability, while resisting deformation and chemical interaction with hydrocarbons, thus enhancing hydrocarbon production.
Implementation Method 1
Conventional proppants generally have a density that is significantly higher than that of the pressurizing fluid stream. As such, conventional proppants tend to settle out of the fracturing fluid stream... lower-density proppants may be desirable
Implementation Method 2
Each crosslinked polymer granule may contain a highly crosslinked polymeric material. The highly crosslinked polymeric material may include a plurality of polyethylene polymer chains and a plurality of chemical crosslinks. The plurality of chemical crosslinks may include chemical crosslinks that covalently bond a given polyethylene polymer chain to another polyethylene polymer chain
Data Source
AI summary
Hydrocarbon wells including crosslinked polymer granules as a proppant, methods of forming the hydrocarbon wells, and methods of operating the hydrocarbon wells. The hydrocarbon wells include a wellbore that extends within a subsurface region and a downhole tubular that extends within the wellbore and defines a tubular conduit. The hydrocarbon wells also include a plurality of perforations formed within the downhole tubular and a plurality of fractures formed within the subsurface region. The hydrocarbon wells further include the proppant positioned within the plurality of fractures. The proppant includes a plurality of crosslinked polymer granules, and each crosslinked polymer granule has a characteristic dimension of at least 100 micrometers and at most 2 millimeters.