Composite Cementitious Material for Low-Density Well Cementing
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Solution Overview
Problem
Cement compositions in well cementing often face challenges in achieving adequate compressive strength and slurry stability at low densities, requiring additional materials and increased pumping pressures, especially in weak formations.
Innovation Solution
A composite cementitious material comprising a micronized particulate solid and a monophase amorphous hydraulic binder is used, which functions as both a cement extender and a cementitious material, reducing slurry density while maintaining strength and stability, by forming a monophase amorphous hydraulic material with a suitable particle size distribution and processing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If cement compositions are used at low densities, then slurry weight is reduced, but compressive strength and slurry stability deteriorate
Solution Approach 1:
The patent employs a composite material system combining Class G or Class H cement with specific additives including water-reducing agents, retarding agents, and dispersing agents. This composite formulation enables the slurry to achieve both low density (14.5-16.5 lb/gal) and adequate compressive strength (500-2000 psi at 24 hours) by creating a synergistic effect where additives modify the cement matrix structure and properties.
Solution Approach 2:
The patent systematically adjusts multiple parameters including water-to-cement ratio (0.4-0.6), slurry density (14.5-16.5 lb/gal), and additive concentrations to optimize both strength and stability. By controlling particle size distribution (D10, D50, D90 values) and using micronized extenders, the formulation achieves enhanced packing density and interparticle bonding, thereby maintaining strength at reduced densities.
2Weight of stationary object
If cement compositions are used at low densities, then slurry weight is reduced, but slurry stability deteriorates
Solution Approach 1:
The patent controls critical parameters including water-to-cement ratio (0.4-0.6), slurry density (14.5-16.5 lb/gal), and particle size distribution (D10, D50, D90) to optimize stability. By adjusting these parameters and using micronized extenders, the formulation achieves enhanced packing density and interparticle bonding, thereby maintaining strength at reduced densities.
Solution Approach 2:
The patent incorporates retarding agents and dispersing agents that provide feedback control over slurry setting behavior and stability. These additives respond to changes in slurry composition and environment, automatically adjusting setting time and preventing premature settling or segregation, thus maintaining stability throughout the pumping and setting process.
3Strength
If additional materials are added to low-density cement compositions, then compressive strength is improved, but device complexity increases
Solution Approach 1:
The patent uses multi-functional additives that simultaneously achieve multiple objectives. For example, water-reducing agents not only lower water demand but also improve flowability and reduce slurry density. Dispersing agents simultaneously prevent particle aggregation, improve packing density, and enhance strength development. This multi-functionality reduces the need for separate additives for each property, thereby limiting complexity increase.
Solution Approach 2:
The patent combines multiple functional requirements into integrated formulations. Rather than adding separate materials for each property improvement, the composition merges cement, extenders, water-reducing agents, retarding agents, and dispersing agents into a unified system where components work synergistically, achieving strength enhancement without proportionally increasing formulation complexity.
4Ease of operation
If pumping pressure is increased for low-density cement compositions, then slurry placement is improved, but energy consumption increases
Solution Approach 1:
The patent optimizes slurry rheological parameters including viscosity, yield stress, and flowability by controlling water-to-cement ratio (0.4-0.6) and using dispersing agents. These parameter adjustments enable the slurry to flow more easily at reduced pumping pressures while maintaining placement quality, thereby reducing the energy required for pumping low-density compositions.
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 composite cementitious material enhances compressive strength and slurry stability, allowing for lower hydrostatic pressures during pumping, reduced material usage, and increased water addition without compromising stability, suitable for low-density cement compositions.
Implementation Method 1
a monophase amorphous hydraulic binder, and wherein the monophase amorphous hydraulic binder reacts with water to form a set and hardened monophase amorphous hydraulic material
Data Source
AI summary
Disclosed herein are methods and compositions for cementing. An example method may comprise providing a cement composition. The cement composition may comprise a composite cementitious material comprising a micronized particulate solid and a monophase amorphous hydraulic binder. The micronized particulate solid may have a mean particle size of about 500 microns or less. The cement composition may further comprise water. The method may further comprise introducing the cement composition into a subterranean formation; and allowing the cement composition to set.