Aqueous Silica Dispersion Stabilization for Hydraulic Cement
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Solution Overview
Problem
Commercially available silica suspensions used in hydraulic cement compositions face issues such as phase separation, agglomeration, and sedimentation, especially at low temperatures, leading to diminished strength and logistical challenges due to high water content, resulting in costly well downtime and storage difficulties.
Innovation Solution
A method for forming tailored aqueous silica suspensions by adjusting the pH with organic acids and adding siliconates to create a stable suspension with high silica powder content, reducing the need for warehousing and transportation of large volumes, and enhancing the mechanical strength of cement compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If commercially available silica suspensions are used in hydraulic cement compositions, then the suspensions provide initial strength enhancement, but phase separation, agglomeration, and sedimentation occur over time leading to diminished strength
Solution Approach 1:
The patent changes the pH parameter of the silica suspension to a range of 2-4 using organic acids, which fundamentally alters the chemical environment to prevent particle aggregation and maintain suspension stability over time, directly addressing the reliability issue while preserving strength enhancement
Solution Approach 2:
The patent creates a composite system by combining silica particles with specific organic acids (oxalic, malic, succinic, or tartaric acid) and siliconate compounds, forming a stable composite suspension that maintains both strength properties and long-term stability without phase separation
2Quantity of substance
If commercially available silica suspensions with 50% active product are used, then the suspensions provide silica content, but large volumes of water require large containers and take up needed space
Solution Approach 1:
The patent changes the concentration parameter by formulating suspensions with 60-80% silica content instead of the conventional 50%, which reduces the volume required to deliver the same amount of active silica product, directly addressing the storage space issue
Solution Approach 2:
The patent applies local quality by concentrating the silica particles more densely in specific regions of the suspension while maintaining stability through pH control, allowing for more efficient space utilization during storage and transportation
3Loss of time
If silica suspensions are stored in warehouse or transported for extended periods, then the suspensions are available when needed, but phase separation and sedimentation cause problems diminishing strength
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the pH to the optimal range of 2-4 and adding stability-modifying compounds during manufacturing, which creates a long-lasting stable formulation that prevents phase separation during extended storage and transportation periods, maintaining strength properties when needed
Solution Approach 2:
The patent introduces organic acids and siliconate compounds as intermediary substances that mediate between the silica particles and water, preventing direct particle aggregation and maintaining suspension stability over extended time periods, thereby preserving strength enhancement capabilities
4Reliability
If the pH of silica suspension is adjusted to 2-4 using organic acids, then the suspension stability is improved and phase separation is reduced, but the formulation complexity increases
Solution Approach 1:
The patent changes the pH parameter to a specific range of 2-4, which simplifies the overall formulation by eliminating the need for complex stabilization mechanisms, as this pH range naturally prevents particle aggregation and maintains suspension stability
Solution Approach 2:
The patent achieves homogeneity by maintaining a uniform pH of 2-4 throughout the suspension, which creates consistent chemical conditions that prevent localized phase separation and simplify the formulation compared to multi-component stabilization systems
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 tailored silica suspensions maintain higher compressive strength over time at various temperatures and reduce the risk of phase separation and sedimentation, allowing for more efficient well operations with reduced storage and handling costs.
Implementation Method 1
adjusting the pH with organic acids
Implementation Method 2
adjusting the pH with organic acids to a value between 2 and 4
Implementation Method 3
adding siliconates to create a stable suspension with high silica powder content
Implementation Method 4
create a stable suspension with high silica powder content, reducing the need for warehousing and transportation of large volumes
Data Source
AI summary
Methods of forming an aqueous silica suspension are provided. The methods include admixing water, an organic acid, a silica powder, and a siliconate under certain conditions. The silica powder includes undensified silica powder in an amount of at least about 50% by weight and has a specific gravity in the range of from about 2.1 to about 2.5, a bulk density in the range of from about 12 lb/ft3 to about 40 lb/ft3, and a water requirement of from about 80 to about 250 at a pH in the range of from about 5.5 to about 7.5. Also provided are aqueous silica suspensions, hydraulic cement compositions, and methods of cementing in a well.