Segmented Nano-Graphene Plugging Drilling Fluid for Borehole Stability
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Solution Overview
Problem
The existing drilling fluids face challenges in stabilizing boreholes during shale gas drilling due to well collapse and poor plugging efficiency in micrometer/nanometer cracks, with water-based fluids lacking sufficient plugging capacity and oil-based fluids causing contamination issues.
Innovation Solution
A strong plugging drilling fluid composition comprising water, bentonite, Na2CO3, a shale inhibitor, a filtrate reducer, an anti-collapse agent, a nanometer plugging agent, a lubricant, and a weighting agent, including modified asphalt, ultra-fine calcium carbonate, and polyethylene glycol surface-modified nano-graphene, which forms a dense blocking barrier to prevent pressure transmission and maintain well stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water-based drilling fluid is used, then contamination is reduced, but plugging capacity in micrometer/nanometer cracks is insufficient
Solution Approach 1:
The plugging system is segmented into three distinct components with different particle sizes: coarse plugging agent (0.1-1mm), fine plugging agent (1-10μm), and nanometer plugging agent (10-100nm). This segmentation allows each component to target specific crack sizes, with the nanometer agent specifically addressing micrometer/nanometer cracks while the larger agents handle larger fractures, achieving comprehensive plugging capacity without contamination
Solution Approach 2:
The drilling fluid employs a composite plugging system combining three types of plugging agents with different particle size distributions. This composite approach integrates the advantages of each material type: coarse agents for structural support and large crack plugging, fine agents for intermediate cracks, and nanometer agents for micrometer/nanometer cracks, achieving superior overall plugging capacity while maintaining water-based fluid benefits
2Ease of manufacture
If existing plugging materials are used, then application is simple, but particle size is too large to enter micrometer/nanometer cracks
Solution Approach 1:
The invention fundamentally changes the particle size parameter of plugging agents by introducing a nanometer-scale component (10-100nm) alongside fine (1-10μm) and coarse (0.1-1mm) agents. This parameter change enables the plugging materials to physically enter and fill micrometer/nanometer cracks that were previously inaccessible to conventional larger particles, while maintaining the simplicity of direct drilling fluid application
3Quantity of substance
If conventional plugging materials are used, then cost is low, but they agglomerate and increase particle size
Solution Approach 1:
The invention introduces surface modification technology as an intermediary process, applying hydrophilic surface treatment to the nanometer plugging agent. This surface modification acts as a mediator that prevents direct agglomeration between nanometer particles and with other plugging agents, maintaining stable particle size distribution and preventing the cost-effective materials from deteriorating through agglomeration
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 composition effectively blocks micrometer/nanometer cracks, reduces hydraulic fracture effects, prevents blockage collapse, and maintains well stability by forming a long-lasting, dense sealing barrier, enhancing drilling fluid performance and reducing contamination risks.
Implementation Method 1
polyethylene glycol surface-modified nano-graphene
Implementation Method 2
nanometer plugging agent is polyethylene glycol surface-modified nano-graphene
Implementation Method 3
The different anti-collapse agents and treatment agents can form a 'force chain network' at the micro-scale contact interface through reasonable compounding and particle diameter grading
Implementation Method 4
form a long-lasting and dense blocking barrier at the adjacent borehole wall
Data Source
AI summary
The invention relates to the field of drilling fluid, and discloses a strong plugging drilling fluid composition and preparation method thereof, and use thereof. The strong plugging drilling fluid composition comprises water, bentonite, Na2CO3, a shale inhibitor, a filtrate reducer, a viscosity reducer, an anti-collapse agent, a nanometer plugging agent, a lubricant and a weighting agent. The shale inhibitor is modified asphalt, the anti-collapse agent is ultra-fine calcium carbonate, and the nanometer plugging agent is polyethylene glycol surface-modified nano-graphene.