Low Density Cementitious Composition Using Limestone and Metakaolin
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cementitious compositions for subterranean applications face challenges in achieving low density while maintaining adequate compressive strength and zonal isolation, often requiring costly lightweight additives like microspheres and foaming agents, which pose environmental concerns and industrial challenges.
Innovation Solution
A cementitious binder comprising a hydraulic binder, metakaolin, silica fume, limestone, and a cementitious accelerator, which when mixed with water, produces a low-density cementitious settable composition with enhanced compressive strength without the need for significant amounts of lightweight additives, achieving densities lower than 13 pounds per gallon with 24-hour compressive strength of at least 500psi at 100F (38°C).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high density cement slurries are used to provide adequate compressive strength, then strength is improved, but pumping pressure and formation damage increase
Solution Approach 1:
The invention changes the density parameter of the cement slurry by incorporating specific filler materials (limestone, fly ash, silica fume) in optimized proportions, achieving low density (less than 13 ppg) while maintaining adequate compressive strength through chemical composition adjustments rather than relying on high density
Solution Approach 2:
The invention uses a composite cementitious composition combining multiple materials including hydraulic binder, limestone, fly ash, silica fume, and water, where each component contributes to both strength development and density control, creating a synergistic effect that resolves the contradiction between strength and weight
2Reliability
If high density cement slurries are used to ensure zonal isolation, then isolation effectiveness is improved, but slurry loss into formations increases
Solution Approach 1:
The invention adjusts the density parameter to match or be slightly higher than the surrounding formation pressures, preventing slurry loss into porous formations while maintaining zonal isolation effectiveness through optimized chemical composition and rheological properties
3Weight of moving object
If lightweight additives are used to reduce slurry density, then density is reduced, but cost and environmental hazards increase
Solution Approach 1:
The invention replaces expensive and environmentally concerning lightweight additives with readily available, inexpensive, and environmentally benign materials such as limestone, fly ash, and silica fume, achieving the same density reduction effect without the harmful side effects
Solution Approach 2:
The invention utilizes industrial by-products (fly ash, limestone dust) that would otherwise be waste materials, converting them into valuable components of the cement slurry, thereby reducing both cost and environmental impact while achieving low density
4Weight of moving object
If high water content is used to achieve low slurry weight, then density is reduced, but mechanical strength development is compromised
Solution Approach 1:
The invention uses a composite binder system combining hydraulic binder with reactive fillers (limestone, fly ash, silica fume) that, when mixed with high water content, undergo chemical reactions to form strength-bearing products, thereby maintaining mechanical strength despite high water content and low density
Solution Approach 2:
The invention changes the chemical composition parameters of the binder system to compensate for the high water content, using reactive fillers that contribute to strength development through pozzolanic reactions and crystallization processes, ensuring adequate mechanical properties are 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 solution provides a cost-effective, environmentally friendly, and high-performance cementitious settable composition with improved mechanical and rheological properties, reducing the reliance on expensive additives and minimizing environmental hazards, while ensuring effective zonal isolation and compressive strength in subterranean applications.
Implementation Method 1
one or more materials having pozzolanic or non-pozzolanic properties
Implementation Method 2
hydraulic binder
Data Source
AI summary
A manufactured cementitious binder includes a hydraulic binder in an amount in the range of from 40 to 75% by weight of the cementitious binder; metakaolin in an amount in the range of from 1 to 30% by weight of the cementitious binder; silica fume in an amount up to 15% by weight of the cementitious binder; limestone in an amount of from 5 to 30% by weight of the cementitious binder, and a cementitious accelerator in a controlled amount of at least 0.5% by weight of the cementitious binder, the cementitious binder providing a cementitious settable composition when added with water, wherein for a density lower than 13 pounds per gallon and of at least 11 pounds per gallon obtained without a lightweight additive, said cementitious settable composition exhibits a 24 hour compressive strength at 100F, as hardened, of at least 500psi.