pH-Responsive Composite Plugging Material for Well Wall Fractures
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Solution Overview
Problem
Existing well wall stabilizing materials lack the ability to actively identify and quickly plug formation fractures in complex underground environments, often requiring high usage amounts and having insufficient plugging capability.
Innovation Solution
A composite material with a polymer matrix and embedded metal ions, where the metal ions are embedded at a rate of at least 90wt%, allowing it to quickly respond to pH changes in the formation environment, forming precipitates to plug fractures effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum-based anti-collapse agents are used to plug formation micro-fractures through chemical reaction, then plugging capability is improved, but usage amount must be greater than 10wt% of drilling fluid resulting in low plugging efficiency
Solution Approach 1:
The patent uses composite materials combining metal ions (Al³⁺, Fe³⁺, Ti⁴⁺, or Zr⁴⁺) with polymer materials (polyacrylamide, polyacrylic acid, or their graft copolymers) to create a synergistic plugging system. The metal ions provide chemical precipitation plugging while the polymer provides physical bridging and adsorption, achieving high plugging capability at low concentrations (0.01-5wt% of drilling fluid).
Solution Approach 2:
The patent exploits pH parameter changes in the formation environment to trigger rapid plugging. The metal ion-polymer complex remains stable at drilling fluid pH but undergoes structural transformation and precipitation when encountering formation micro-fractures with different pH characteristics, enabling responsive plugging without requiring high concentrations.
2Reliability
If well wall stabilizing materials are used in complex underground formations, then well wall stability is improved, but the materials lack the ability to actively identify and quickly plug formation fractures
Solution Approach 1:
The metal ion-polymer complex acts as a feedback-responsive plugging agent that senses formation conditions (pH, ionic composition) and automatically adjusts its plugging behavior. The material responds to formation environment feedback by undergoing structural changes that enhance precipitation and adsorption on fracture surfaces, enabling active identification and rapid plugging.
Solution Approach 2:
The plugging agent performs self-service by autonomously responding to formation conditions without external control. The metal ion-polymer complex automatically precipitates and adheres to fracture surfaces when encountering appropriate pH and ionic conditions, enabling self-directed plugging action that adapts to the specific formation environment.
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 composite material achieves precise response and matching with the formation environment, enhancing plugging efficiency with a small amount, and exhibits high cycling stability.
Implementation Method 1
an aluminum compound may undergo morphological changes of different pH values, thereby weakening shale expansion, and plugging a pore throat and a micro-fracture through electrical neutralization, ion adsorption and chemical precipitation
Implementation Method 2
plugging a pore throat and a micro-fracture through electrical neutralization, ion adsorption and chemical precipitation
Implementation Method 3
plugging a pore throat and a micro-fracture through electrical neutralization, ion adsorption and chemical precipitation
Data Source
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Figure 6a~8
AI summary
The present disclosure relates to the technical field of drilling, in particular to a composite material, a composition, a drilling fluid, and a method for plugging formation well wall fractures. The composite material includes a polymer matrix and metal ions embedded in the polymer matrix, an embedding rate of the metal ions is not less than 90wt%, and turbidity of an aqueous solution of the composite material is not less than 1000 NTU under a condition of pH≤8. The composite material can actively and quickly identify a change in a formation environment based on a difference in pH values between the drilling fluid and the formation environment, and achieve a precise response and precise matching with a formation well wall fracture environment, and a small amount of composite material can effectively increase a plugging rate of the formation well wall fracture.