Set-Delayed Cement Compositions Mitigating Contamination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Set-delayed cement compositions face challenges such as gelation issues and contamination with residual cementitious matter, which limit their effectiveness and efficiency in subterranean cementing operations, especially at lower temperatures and during large-scale manufacturing.
Innovation Solution
The use of set-delayed cement compositions comprising water, pumice, hydrated lime, and a combination of primary and secondary set retarders, along with a dispersant, which remain pumpable for extended periods and develop compressive strength at low temperatures, while the secondary retarders mitigate contamination effects by delaying setting and improving mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If set-delayed cement compositions are prepared in advance for subterranean cementing operations, then the compositions can be stored prior to use and capital/operational expenditures are reduced, but the compositions may experience gelation issues that limit their use and effectiveness
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating specific retarders (sugar, starch, or their derivatives) and controlled amounts of Class G or Class H cement to adjust the setting characteristics. This allows the composition to maintain pumpable consistency during extended storage while preventing unwanted gelation, thus resolving the contradiction between storage time and reliability.
2Duration of action of moving object
If set-delayed cement compositions are prepared with Portland cement to achieve extended pumpable state, then the compositions can be stored for extended periods, but undesired gelation issues occur that limit their effectiveness
Solution Approach 1:
The patent creates a composite cement composition by combining Class G or Class H cement with specific retarders (sugar, starch, or their derivatives) in controlled proportions. This composite formulation achieves extended pumpable duration (up to 7 days or more) while preventing gelation issues that plague pure Portland cement systems, thus resolving the contradiction between duration and reliability.
3Strength
If set-delayed cement compositions are prepared with hydrated lime and quartz, then the compositions can achieve reasonable compressive strengths, but they have limited use at lower temperatures as they may not develop sufficient compressive strength
Solution Approach 1:
The patent modifies the composition by incorporating Class G or Class H cement (which has better low-temperature setting characteristics than hydrated lime-quartz systems) along with retarders. This parameter change enables the composition to develop adequate compressive strength at lower temperatures (including below 50°F) while maintaining extended pumpable state, thus resolving the contradiction between strength and temperature adaptability.
4Productivity
If large batch mixers are used during manufacturing of set-delayed cement compositions, then large-scale production is achieved, but the compositions become contaminated with residual cementitious matter from previous operations
Solution Approach 1:
The patent converts the harmful effect of residual cementitious contamination into a beneficial feature by formulating the composition with retarders (sugar, starch, or their derivatives) that counteract the contaminating effect. The contamination that would normally cause premature setting is instead used to extend the pumpable state when combined with these retarders, thus resolving the contradiction between productivity and harmful factors.
5Object-affected harmful factors
If thorough cleaning of mixers is performed before transitioning to new cement composition, then contamination is reduced, but manufacturing cost increases and efficiency decreases
Solution Approach 1:
The patent eliminates the need for thorough cleaning by incorporating retarders (sugar, starch, or their derivatives) that neutralize the effect of residual cementitious contamination. The formulation is designed to tolerate and even benefit from the contamination, converting what would be a harmful factor requiring costly cleanup into an acceptable condition that maintains composition performance, thus resolving the contradiction between contamination level and manufacturing efficiency.
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 compositions effectively remain in a pumpable state for extended periods, develop reasonable compressive strength at low temperatures, and are resistant to contamination, enhancing their suitability and efficiency in subterranean cementing operations, particularly in formations with lower bottom hole static temperatures.
Implementation Method 1
set-delayed cement compositions comprising water, pumice, hydrated lime, and a combination of primary and secondary set retarders
Data Source
AI summary
Methods and compositions for cementing are disclosed. Embodiments include a method of cementing comprising: providing a set-delayed cement composition comprising water, pumice, hydrated lime, a primary set retarder, a secondary set retarder; activating the set-delayed cement composition to produce an activated cement composition; introducing the activated cement composition into a subterranean formation; and allowing the activated cement composition to set in the subterranean formation.