Nanographene Plugging Agent for Shale Borehole Stability
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Solution Overview
Problem
Conventional plugging materials used in oil-based drilling fluids are prone to agglomeration, have poor pressure-bearing capacity, and fail to effectively block nano-scale micro-fractures and pores, leading to borehole wall instability in shale formations.
Innovation Solution
A method to prepare nanographene by reacting graphite with oxidizing agents and intercalating agents, followed by air-flow exfoliation, resulting in a material with an average particle diameter of 110-750 nm, excellent lipophilicity, and high pressure-bearing capacity, which can be used as a plugging agent in oil-based drilling fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plugging materials with particle size of 0.1-100 μm are used, then they can plug larger fractures and pore throats, but they cannot effectively block nano-scale micro-fractures (1-10 μm) due to size mismatch
Solution Approach 1:
The patent changes the particle size parameter of plugging materials from conventional 0.1-100 μm to nanometer scale (1-100 nm), which matches the size of nano-scale micro-fractures and pores in shale formations, enabling effective plugging where conventional materials fail
Solution Approach 2:
The patent segments the plugging material into ultra-fine nanometer particles through chemical exfoliation and mechanical grinding, creating a distribution of particle sizes that can penetrate and block various scales of fractures and pores
2Manufacturing precision
If nanometer plugging materials are used to block nano-scale fractures, then they can reach the target pores, but they aggregate due to high specific surface energy and poor dispersion, reducing plugging effectiveness
Solution Approach 1:
The patent introduces surface modification agents as intermediaries that adsorb onto nanometer particles, providing steric or electrostatic repulsion to prevent aggregation and improve dispersion stability in drilling fluids
Solution Approach 2:
The patent creates composite plugging materials by combining nanometer particles with dispersants and surface modifiers, forming a stable colloidal system that maintains particle separation and prevents aggregation
3Manufacturing precision
If nanometer plugging materials are used to block pores, then they can achieve fine plugging, but they have poor pressure-bearing capacity and cannot block pressure transmission
Solution Approach 1:
The patent merges nanometer particles into a three-dimensional network structure or bridge-across configuration in pore throats, where multiple particles work together to distribute and bear pressure loads, achieving both fine plugging and adequate pressure resistance
Solution Approach 2:
The patent develops composite plugging systems combining nanometer particles with binders or formative agents that create a cohesive mud cake structure, providing both fine plugging capability and mechanical strength for pressure bearing
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 nanographene effectively plugs micro/nano-scale pores and fractures, improving borehole wall stability and pressure-bearing capability, while maintaining desirable rheological properties and adaptability in drilling fluids.
Implementation Method 1
carrying out a first reaction by contacting a raw material graphite and a first oxidizing agent with an intercalating agent to obtain a modified graphite
Implementation Method 2
carrying out a first reaction by contacting a raw material graphite and a first oxidizing agent with an intercalating agent to obtain a modified graphite
Implementation Method 3
subjecting the graphene pre-product to an air-flow exfoliation to prepare a nanographene
Data Source
AI summary
A nanographene, a preparation method thereof, and uses thereof are disclosed. The method of preparing the nanographene includes the steps: (1) carrying out a first reaction by contacting a raw material graphite and a first oxidizing agent with an intercalating agent to obtain a modified graphite; (2) performing a second reaction by contacting the modified graphite and an acid with a second oxidizing agent to obtain a graphene pre-product; and (3) subjecting the graphene pre-product to an air-flow exfoliation to prepare a nanographene. An oil-based drilling fluid containing the nanographene produced by the method is also disclosed.