Set-Delayed Cement Activators for Low-Temperature Strength
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Solution Overview
Problem
Set-delayed cement compositions used in subterranean cementing operations face challenges such as gelation issues with Portland cement and limited compressive strength development at lower temperatures, making them less effective in certain subterranean formations.
Innovation Solution
A method using a set-delayed cement composition comprising water, pumice, hydrated lime, and a set retarder, activated with a cement set activator containing nanosilica or polyphosphate, which remains pumpable for extended periods and develops reasonable compressive strengths at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If set-delayed cement compositions are prepared with Portland cement, then they can be stored for extended periods, but they experience undesired gelation issues that limit their use and effectiveness
Solution Approach 1:
The patent changes the chemical composition parameters by substituting Portland cement with alternative cementitious materials (such as Class F fly ash, ground granulated blast furnace slag, or natural pozzolans) and adjusting the water-to-cement ratio. These parameter changes allow the cement composition to remain stable and pumpable for extended storage periods without experiencing gelation issues, while still achieving desired compressive strengths after placement.
2Duration of action of stationary object
If set-delayed compositions use hydrated lime and quartz, then they remain pumpable for extended periods, but they do not develop sufficient compressive strength at lower temperatures
Solution Approach 1:
The patent employs composite cementitious systems combining multiple materials such as Class F fly ash, ground granulated blast furnace slag, natural pozzolans, and hydrated lime in specific proportions. These composite materials provide both extended pumpable duration and sufficient compressive strength development at lower temperatures by leveraging the synergistic effects of different cementitious components that react differently to temperature variations.
Solution Approach 2:
The patent optimizes the water-to-cement ratio and additive concentrations to enhance early-age strength development at low temperatures while maintaining pumpability. Specific chemical additives are introduced to accelerate hydration reactions under cold conditions, enabling the composition to achieve required compressive strengths even when stored and transported for extended periods before placement in cold subterranean formations.
3Ease of manufacture
If cement composition is prepared in advance for storage and transport, then capital expenditures are reduced, but it becomes problematic to activate while maintaining acceptable thickening times and compressive strength development
Solution Approach 1:
The patent divides the cement composition into separate components that can be stored independently and mixed shortly before placement. This segmentation allows the cementitious materials, water, and chemical additives to be prepared in advance and stored separately, then combined on-site to initiate setting. This approach maintains activation efficiency and acceptable thickening times while still providing the benefits of advance preparation and reduced capital expenditures for on-site bulk storage and mixing equipment.
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 allows for extended storage and transportation of the cement composition while achieving desirable thickening times and compressive strength development, enhancing the effectiveness of cementing operations in various subterranean conditions.
Implementation Method 1
activating the set-delayed cement composition with a cement set activator, wherein the cement set activator comprises at least one activator selected from the group consisting of nanosilica, a polyphosphate, and combinations thereof
Implementation Method 2
activating the set-delayed cement composition with a cement set activator, wherein the cement set activator comprises at least one activator selected from the group consisting of nanosilica, a polyphosphate, and combinations thereof
Implementation Method 3
a set-delayed cement composition comprising water, pumice, hydrated lime, and a set retarder
Data Source
AI summary
Disclosed herein are cement compositions and methods of using set-delayed cement compositions in subterranean formations. A method of cementing in a subterranean formation, may comprise providing a set-delayed cement composition comprising water, pumice, hydrated lime, and a set retarder, activating the set-delayed cement composition with a cement set activator, wherein the cement set activator comprises at least one activator selected from the group consisting of nanosilica, a polyphosphate, and combinations thereof, introducing the set-delayed cement composition into a subterranean formation, and allowing the set-delayed cement composition to set in the subterranean formation.