Volcanic Ash Cement Composition for Low-Emission Well Cementing
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Solution Overview
Problem
Existing cement compositions for well cementing require significant amounts of Portland cement, which are energy-intensive and contribute to greenhouse gas emissions, and there is a need for compositions with reduced Portland cement content that maintain effective zonal isolation and well performance.
Innovation Solution
Incorporating volcanic ash into cement compositions, ranging from 10% to 70% by weight of cement (BWOC), along with Portland cement, water, and optional additives like defoamers, gelling agents, and retarders, to create pumpable cement compositions with reduced environmental impact and suitable rheological properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If significant amounts of Portland cement are used in cement compositions, then zonal isolation and well performance are ensured, but energy consumption and greenhouse gas emissions increase
Solution Approach 1:
The patent changes the compositional parameters of the cement slurry by incorporating volcanic ash (10-70% BWOC) to replace a portion of Portland cement (10-85 wt%), thereby reducing the energy-intensive component while maintaining the required zonal isolation performance through the combined properties of the composite material system
Solution Approach 2:
The patent creates a composite cement material system combining Portland cement with volcanic ash, where the two materials work together to provide the necessary mechanical strength and sealing properties for zonal isolation, reducing reliance on energy-intensive Portland cement alone
2Reliability
If significant amounts of Portland cement are used in cement compositions, then zonal isolation and well performance are ensured, but greenhouse gas emissions increase
Solution Approach 1:
The patent modifies the chemical composition parameters by integrating volcanic ash (10-70% BWOC) with Portland cement (10-85 wt%), reducing the proportion of clinker-based cement that generates high greenhouse gas emissions during production, while preserving the functional performance for zonal isolation
Solution Approach 2:
The patent develops a composite cement formulation combining Portland cement with volcanic ash, leveraging the pozzolanic properties of volcanic ash to contribute to strength development and sealing capability, thereby reducing the environmental footprint associated with Portland cement production
3Use of energy by moving object
If volcanic ash content is increased to reduce Portland cement content, then energy consumption and emissions are reduced, but rheological properties and thickening times must be maintained
Solution Approach 1:
The patent optimizes the volumetric ratio parameters of volcanic ash (10-70% BWOC) and Portland cement (10-85 wt%) to achieve the desired balance between energy reduction and maintaining pumpable rheological properties, ensuring the slurry remains operable within standard well cementing parameters
Solution Approach 2:
The patent applies different functional roles to different components: Portland cement provides early strength and structural integrity, while volcanic ash contributes to later strength development and rheological modification, allowing each material to optimize its local contribution to overall performance
4Object-generated harmful factors
If volcanic ash content is increased to reduce Portland cement content, then greenhouse gas emissions are reduced, but compressive strength and thickening time must be maintained
Solution Approach 1:
The patent adjusts the compositional parameters to include volcanic ash (10-70% BWOC) combined with Portland cement (10-85 wt%), leveraging the synergistic effect where volcanic ash undergoes pozzolanic reaction to form calcium silicate hydrates that contribute to long-term compressive strength, offsetting the reduced Portland cement content
Solution Approach 2:
The patent creates a composite binding system where Portland cement provides initial hydraulic setting and early strength, while volcanic ash acts as a supplementary cementitious material that continues to react with calcium hydroxide to produce additional binding phases, ensuring sustained compressive strength development
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 volcanic ash-based cement compositions achieve reduced energy consumption and greenhouse gas emissions while maintaining high compressive strengths and suitable thickening times for well cementing applications, particularly in shallow sections of oil and gas wells.
Implementation Method 1
The volcanic ash can reduce the amount of Portland cement necessary to provide a cement composition suitable for shallow-section applications
Implementation Method 2
a cement slurry is typically pumped into the annulus between the rock formations of the wellbore and the steel casing
Data Source
AI summary
The present disclosure relates to cement compositions including Portland cement and volcanic ash. An exemplary cement composition includes about 10 wt % to about 85 wt % of Portland cement, and about 10% by weight of cement (BWOC) to about 70% BWOC of volcanic ash.