Composite Cement Accelerators Using Sodium Chloride and Sulfate
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Solution Overview
Problem
Composite cement compositions with reduced Portland cement content face challenges in achieving enhanced compressive strength due to the differing functions of conventional accelerators, which can result in suboptimal performance in well cementing applications.
Innovation Solution
Incorporating a combination of sodium chloride and sodium sulfate as accelerators in composite cement compositions, along with pozzolans and optional Portland cement, to enhance compressive strength, with the sodium chloride and sodium sulfate ratio optimized for synergistic effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional accelerators are used in composite cement compositions with reduced Portland cement content, then cost is reduced, but compressive strength is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the accelerator by combining sodium chloride and sodium sulfate in specific ratios (0.1:1 to 1:0.1 by weight). This parameter modification allows the accelerator to effectively enhance compressive strength in composite cement compositions with reduced Portland cement content, resolving the contradiction between cost reduction and strength maintenance.
Solution Approach 2:
The patent uses a composite accelerator system combining two different chemical substances (sodium chloride and sodium sulfate) rather than a single conventional accelerator. This composite approach creates synergistic effects that improve compressive strength development in low-Portland cement composite cements, addressing the strength deficiency while maintaining cost benefits.
2Loss of time
If conventional accelerators are used in composite cement compositions, then setting time is reduced, but compressive strength enhancement is insufficient
Solution Approach 1:
The patent modifies the chemical parameters of the accelerator system by using a specific combination of sodium chloride and sodium sulfate. This parameter change enables dual functionality: maintaining rapid setting characteristics while simultaneously achieving significant compressive strength enhancement (up to 300% improvement) in composite cement compositions.
Solution Approach 2:
The composite accelerator system performs multiple functions simultaneously: it acts as both a setting time reducer and a compressive strength enhancer. This multi-functionality resolves the contradiction between achieving fast setting and obtaining adequate strength development in composite cement compositions.
3Quantity of substance
If Portland cement content is reduced in composite cement compositions, then cost is reduced, but accelerator performance deteriorates
Solution Approach 1:
The patent changes the chemical composition and concentration parameters of the accelerator to optimize its performance in low-Portland cement environments. The specific ratio combination of sodium chloride and sodium sulfate (0.1:1 to 1:0.1 by weight) ensures reliable and consistent accelerator function even when Portland cement content is significantly reduced.
Solution Approach 2:
The patent uses inexpensive salt-based accelerators (sodium chloride and sodium sulfate) that can be used in optimized combinations to compensate for reduced Portland cement content. These cost-effective accelerators provide reliable performance in composite cement systems, maintaining accelerator functionality while reducing dependence on expensive Portland cement.
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 use of sodium chloride and sodium sulfate accelerators significantly increases compressive strength by up to 300% in composite cement compositions, particularly in low Portland cement content mixes, improving the efficiency and effectiveness of well cementing operations.
Implementation Method 1
Accelerators speed up the time required for a cement composition to become hardened in a reaction process that shortens WOC (Wait On Cement) time... This reaction process may be referred to as cement hydration whereby water induces chemical reactions that ultimately lead to bonding.
Implementation Method 2
Accelerators essentially speed the reaction with water, which in turn reduces (a) thickening time and/or increases (b) early compressive strength development after set.
Data Source
AI summary
Disclosed herein are methods, compositions, and systems for cementing. A method of cementing may comprise: providing a composite cement composition comprising a pozzolan, an accelerator, and water, wherein the accelerator comprises a chloride salt and a sulfate salt, wherein the composite cement composition is free of Portland cement or comprises Portland cement in an amount of about 50% by weight of cementitious components or less; and allowing the composite cement composition to set.