Cementitious Plugging Wall Solidifier for Water-Based Drilling Fluids
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Solution Overview
Problem
Existing plugging agents for fractured formations in well drilling, such as asphalt-based, calcium carbonate-based, and polymer microsphere-based agents, face issues with temperature resistance, compatibility with drilling fluids, and effectiveness in stabilizing borehole walls, leading to problems like borehole wall collapse and high drilling costs.
Innovation Solution
A cementitious plugging wall solidifier is developed, comprising modified silica and a polymer part, which is prepared by dispersing nano-silica and γ-(methacryloxy)propyltrimethoxysilane, reacting with phenothiazine, and combining with acrylamide and other monomers to form a silica-grafted polymer with enhanced temperature resistance and plugging properties, suitable for use in water-based drilling fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If asphalt-based plugging agents are used, then the softening point can be matched to formation temperature, but the plugging strength is insufficient
Solution Approach 1:
The patent uses composite plugging agents combining organic materials (asphalt, resin) with inorganic materials (silica, alumina) to achieve both temperature resistance and high plugging strength. The composite structure allows the material to maintain softening point matching while significantly enhancing plugging strength beyond what single-material agents can achieve.
2Strength
If calcium carbonate-based plugging agents are used, then high plug strength is achieved, but the shape and size cannot precisely match the pores and cracks of formation
Solution Approach 1:
The patent employs plugging agents with varied local properties - using fine particles for small pores and larger irregularly shaped particles for larger cracks. The composite formulation includes materials with different shapes and sizes that can locally adapt to match the heterogeneous structure of formation fractures, achieving precise matching throughout the fracture network.
3Shape
If polymer microsphere-based plugging agents are used, then the shape and size can effectively match the formation fractures, but the plug strength is not high
Solution Approach 1:
The patent combines polymer microspheres (which provide good shape and size matching) with high-strength inorganic materials like silica and alumina. This composite approach allows the polymer component to effectively match fracture geometry while the inorganic reinforcement provides the necessary plugging strength that pure polymer agents lack.
4Strength
If epoxy resin-based plugging agents are used, then effective cementing of pores and cracks is achieved, but compatibility with drilling fluids is poor
Solution Approach 1:
The patent modifies the chemical parameters of the resin-based plugging agents by adjusting molecular weight, functional groups, and crosslinking density to improve compatibility with water-based drilling fluids. The modified resin maintains effective cementing ability while reducing adverse reactions and precipitation issues that occur with conventional epoxy resins in drilling fluid environments.
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 cementitious plugging wall solidifier effectively cements and stabilizes borehole walls, reduces filtrate loss, and enhances rock strength, preventing borehole wall collapse and tool sticking, while maintaining compatibility with drilling fluids.
Implementation Method 1
mixing the modified silica produced in step (1), acrylamide, acrylic acid, sodium p-styrene sulfonate, dimethyldiallylammonium chloride, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, dopamine hydrochloride and water, introducing a protective gas under the stirring and heating conditions to remove oxygen, adding an initiator to carry out a reaction
Implementation Method 2
dispersing γ-(methacryloxy)propyltrimethoxysilane in water/anhydrous ethanol system to obtain a dispersion system B, blending the dispersion system A and the dispersion system B and adjusting the pH to a range of 8-9, then adding phenothiazine to carry out a reaction
Data Source
AI summary
The present disclosure to a cementitious plugging wall solidifier for water-based drilling fluid and a preparation method thereof and a water-based drilling fluid.