Block Copolymer Coated Proppants for Crush Resistance
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Solution Overview
Problem
Conventional uncoated ceramic proppants break down in wet conditions and high downhole temperatures, leading to reduced crush resistance and the release of fines that can restrict flow conductivity in oil and gas production, necessitating the development of coated proppants with improved durability and fines retention.
Innovation Solution
A block copolymer coating, such as polystyrene-polyethylenebutylene-polystyrene-grafted-maleic anhydride (PS-PEB-PS-g-MA), is applied to proppants, providing elastic properties and crosslinking to enhance crush resistance and prevent fine release, with curing temperatures below 250°C and partial or full curing before use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional uncoated ceramic proppants are used, then the proppants can be applied in hydraulic fracturing operations, but they break down in wet conditions and high temperatures causing reduced crush resistance and fine release
Solution Approach 1:
The patent applies a polymer coating layer on ceramic proppant particles to create a composite structure. The coating comprises a thermoplastic polymer matrix with dispersed crosslinking agents and fillers, forming a composite material that combines the hardness of ceramic with the flexibility and adhesive properties of polymer, thereby preventing particle breakage and fine release under downhole conditions
Solution Approach 2:
The patent changes the physical and chemical parameters of the proppant surface by applying a coating layer with specific glass transition temperature (Tg) range (50-150°C), crosslinking density, and compositional ratios. These parameter changes enable the proppant to maintain structural integrity and crush resistance at downhole temperatures while preventing fine particle generation
2Reliability
If proppant coatings are applied to protect from degradation, then crush resistance improves, but conventional coating techniques require curing temperatures greater than 250°C
Solution Approach 1:
The patent selects thermoplastic polymers with glass transition temperatures (Tg) between 50-150°C, allowing the coating to be applied and cured at lower temperatures (below 250°C) while still achieving adequate adhesion and protective properties. The crosslinking agents further enhance durability without requiring high-temperature curing
Solution Approach 2:
The patent introduces crosslinking agents as intermediaries that form chemical bonds within the polymer matrix at moderate temperatures. These crosslinking agents (such as silanes or isocyanates) create a three-dimensional network structure that enhances coating durability and adhesion to the ceramic substrate without requiring high-temperature processing
3Reliability
If proppants are crushed under downhole stress, then fines are released which may migrate into the formation, but coated proppants increase surface area to distribute crush stress
Solution Approach 1:
The patent applies a resilient polymer coating layer before the proppant enters the downhole environment. This coating acts as a cushioning layer that absorbs and distributes crush stresses, preventing the ceramic core from fracturing and generating fines. The coating's elastic properties allow it to deform under stress and return to shape, protecting the brittle ceramic particle
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 proppants exhibit reduced crush percentage and improved compressive strength, maintaining integrity under high downhole pressures and temperatures, while encapsulating fines to prevent flow restriction, thereby enhancing oil and gas production efficiency.
Implementation Method 1
the proppant coating increases the surface area of the particle; therefore, the crush stress is distributed over a larger area of the coated proppant particle
Implementation Method 2
the coating encapsulates and adheres to the proppant material such that at least some of the fines that may be generated when the coated proppant is crushed and trapped within or onto the block copolymer coating
Implementation Method 3
An elastic coating improves the crush resistance strength of the coated proppants such that the coated proppants may sustain greater closure stress without cracking the proppant particle
Implementation Method 4
the polymer includes a polystyrene-polyethylenebutylene-polystyrene-grafted-maleic anhydride (PS-PEB-PS-g-MA) co-polymer... The crosslinked block copolymer proppant coating is a crosslinked block copolymer that is the resultant of a reaction between a block copolymer and a crosslinking agent
Data Source
AI summary
Methods for producing proppants with block copolymer proppant coating include coating proppant particles with the block copolymer proppant coating to produce coated proppants with block copolymer proppant coating. The block copolymer proppant coating is a block copolymer composition having at least one copolymer backbone. Each copolymer backbone comprises at least two hard segments and a soft segment disposed between the at least two hard segments. Additionally, a proppant comprising a proppant particle and a block copolymer proppant coating includes a block copolymer composition having at least one copolymer backbone, in which each copolymer backbone comprises at least two hard segments. A soft segment is disposed between the at least two hard segments. The copolymer backbone has at least one anhydride group grafted onto the soft segment. Furthermore, the anhydride group is crosslinked by an amine-containing crosslinker.