pH-Responsive Nano-Gel Plugging Material for Carbonate Fractures
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Solution Overview
Problem
Rapid identification and plugging of fractures and micro-cavities in Ordovician carbonate rocks are challenging due to high calcium ion content and pH variability, leading to seepage and leakage issues in petroleum exploration and rock excavation.
Innovation Solution
A pH-responsive nano-gel plugging material composed of water, an emulsifier, an acrylic terpolymer, and a vinyl pyridine-based compound, which remains shrunk in alkaline environments but swells dramatically in acidic conditions, allowing for automatic identification and effective plugging of fractures and micro-cavities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional plugging materials are used in Ordovician carbonate strata, then they can provide some plugging effect, but they cannot rapidly identify and effectively plug fractures and micro-cavities due to high calcium ion content and pH variability
Solution Approach 1:
The plugging material utilizes pH-responsive swelling behavior to adapt to different environmental conditions. The material remains in a shrunk state in alkaline drilling fluid (pH >9) but instantly swells when encountering acidic fractured strata (pH 5.0-7.0), enabling rapid identification and effective plugging of fractures and micro-cavities
Solution Approach 2:
The plugging material transitions from a static shrunk state in alkaline environment to a dynamic swollen state in acidic environment. This dynamic response allows the material to automatically identify leakage strata and expand to fill fractures and micro-cavities, achieving both rapid identification and effective plugging
2Reliability
If the plugging material swells in alkaline drilling fluid environment, then it can plug fractures effectively, but it would cause premature plugging before reaching the target strata
Solution Approach 1:
The plugging material is designed with pH-responsive properties that prevent swelling in alkaline environments (pH >9) while triggering rapid swelling in acidic environments (pH 5.0-7.0). This parameter-based response ensures the material remains stable during transport in alkaline drilling fluid and only activates when encountering the target acidic fractured strata
Solution Approach 2:
The pH difference between alkaline drilling fluid and acidic fractured strata serves as an intermediary trigger mechanism. This natural pH gradient acts as a switch that controls when and where the plugging material swells, ensuring timely and location-specific plugging without premature activation
3Productivity
If the plugging material is designed for rapid swelling, then it can quickly plug fractures, but it may not provide sufficient stability and durability in the plugging structure
Solution Approach 1:
The plugging material employs a composite structure combining crosslinked polyacrylamide gel matrix with pH-responsive components. This composite design enables both rapid swelling response in acidic environments and long-term stability in the swollen state, achieving rapid plugging while maintaining structural integrity and durability
Solution Approach 2:
The plugging material utilizes a phase transition from a shrunk gel state in alkaline environment to a swollen gel state in acidic environment. This phase transition enables rapid volume expansion for quick plugging, while the crosslinked gel structure ensures stability and durability once the swollen state is achieved
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 material provides a rapid and effective plugging solution by swelling significantly in acidic environments, thereby preventing leakage and achieving excellent plugging results in Ordovician carbonate rocks.
Implementation Method 1
The above-mentioned nano-gel material entering into the acidic environment swells and expands rapidly
Implementation Method 2
2-3 parts of an emulsifier
Implementation Method 3
25-35 parts of an acrylic terpolymer
Data Source
AI summary
Provided in the present invention are a pH-responsive nano-gel plugging material, and a preparation method therefor and the use thereof. The pH-responsive nano-gel plugging material comprises the following raw materials in parts by mass: 50-70 parts of water, 2-3 parts of an emulsifier, 25-35 parts of an acrylic terpolymer, 10-15 parts of a polyalcohol compound, and 10-20 parts of a vinyl pyridine compound. The pH-responsive nano-gel plugging material can be applied to the plugging of Ordovician carbonate rock fractures and micro-karst cave strata, and can automatically identify Ordovician carbonate rock fractures and micro-karst cave leaking layers and realize effective blocking thereof.