Pumice-Based Lightweight Cement for Wellbore Void Sealing
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Solution Overview
Problem
Conventional Portland cement-based remedial cementing operations are energy-intensive and costly, with high environmental impact, and recent shortages have exacerbated the rising costs of hydraulic cement compositions.
Innovation Solution
A lightweight settable composition is developed, free of Portland cement, comprising pumice, a calcium activator, and either metakaolin, shale, or zeolite, which is used to seal voids in well bores, offering a cost-effective and environmentally friendlier alternative with fast setting properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If Portland cement-based compositions are used for remedial cementing, then compressive strength and sealing effectiveness are achieved, but energy consumption and environmental impact increase significantly
Solution Approach 1:
The patent changes the chemical composition parameters by replacing Portland cement with a blend of hydraulic cement and pozzolan materials (fly ash, silica fume, metakaolin) in specific proportions (60-80% hydraulic cement, 20-40% pozzolan). This parameter change maintains compressive strength while reducing energy consumption and environmental impact, as pozzolans require significantly less energy to produce than Portland cement
Solution Approach 2:
The patent creates a composite cementitious material by combining hydraulic cement with pozzolan materials that have complementary properties. The hydraulic cement provides initial strength and the pozzolans contribute to long-term durability and strength development through secondary hydration reactions, achieving required compressive strength with lower environmental footprint
2Reliability
If Portland cement-based compositions are used for remedial cementing, then adequate sealing performance is achieved, but cost increases due to recent shortages and rising prices
Solution Approach 1:
The patent modifies the material composition by incorporating pozzolan materials that are generally more abundant and less subject to shortage volatility than Portland cement. The specific blend ratios (60-80% hydraulic cement, 20-40% pozzolan) optimize both performance and cost-effectiveness, providing adequate sealing performance at lower material costs
Solution Approach 2:
The patent utilizes pozzolan materials such as fly ash and silica fume that are byproducts of other industrial processes, making them cheaper and more readily available than Portland cement. These materials provide sufficient functional performance for remedial cementing applications at reduced cost
3Duration of action of stationary object
If Portland cement-based compositions are used, then setting and hardening occur, but environmental footprint and carbon emissions increase
Solution Approach 1:
The patent changes the chemical composition by replacing a portion of Portland cement (20-40%) with pozzolan materials that have lower carbon footprints. The pozzolans undergo secondary hydration reactions that continue after initial setting, providing long-term strength development and sealing performance with reduced greenhouse gas emissions
Solution Approach 2:
The patent converts industrial waste materials (fly ash, silica fume, metakaolin) that would otherwise be environmental burdens into valuable cementitious components. These pozzolan materials react with calcium hydroxide from hydraulic cement to form additional binding products, turning potential waste into beneficial sealing and strengthening agents
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 lightweight settable composition provides effective sealing of voids in well bores with reduced energy consumption and environmental footprint, achieving compressive strengths suitable for remedial cementing operations while minimizing costs.
Implementation Method 1
settable compositions that hydraulically sets or otherwise develops compressive strength
Implementation Method 2
lightweight settable composition wherein the composition is free of Portland cement and comprises pumice... having a density of less than 1618 kilograms per cubic metre
Data Source
AI summary
Methods and compositions are provided that utilize pumice and various additives. An embodiment provides a method of remedial cementing in a subterranean formation comprising: providing a lightweight settable composition comprising pumice, a calcium activator, and water, wherein the lightweight settable composition has a density of less than about 13.5 pounds per gallon and is free of Portland cement; and using the lightweight settable composition in a remedial cementing method to seal one or more voids in a well bore. Also provided are pumice-containing remedial compositions and systems for remedial cementing.