Wood-Based Cement Additive for Slurry Density Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cement additives for reducing the weight of cement slurries, such as microsilica and glass spheres, are prone to crushing and increased viscosity during mixing, and are either expensive or limited in supply, making them unsuitable for all applications, especially in the drilling industry.
Innovation Solution
A wood-based cement additive is developed by pelletizing refined sawdust under high pressure to create brittle pellets that can be crumbled and screened into specific sizes, maintaining a strong bond with cement and preventing unintended increases in viscosity or density, using hardwood fibers that do not absorb water, thus forming a slurry with reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If glass spheres or microspheres are used as weight-reducing additives, then the density of cement slurry is reduced, but the additives are susceptible to crushing during mixing and pumping, leading to increased slurry density and viscosity
Solution Approach 1:
The patent uses wood fiber pellets as a disposable, cost-effective alternative to expensive glass spheres. The pellets are designed to maintain structural integrity during mixing and pumping, providing weight reduction without the crushing problems of glass spheres. The pellets are consumed in the cement matrix, providing their function without needing to be recovered or reused.
Solution Approach 2:
The patent changes the physical parameters of the additive by using wood fiber pellets with specific density, size, and shape characteristics. The pellets have a density lower than cement but higher than glass spheres, and their fibrous structure provides resistance to crushing while maintaining weight reduction benefits. The pelletization process creates a controlled porous structure that balances density reduction with mechanical strength.
2Strength
If microsilica is used to improve compressive strength and bond strength, then the cement performance is enhanced, but the cost increases and supply is limited
Solution Approach 1:
The patent replaces expensive microsilica with wood fiber pellets, which are abundant, inexpensive, and readily available. The wood fiber pellets provide sufficient bonding and strength enhancement for cement applications without the cost and supply constraints of microsilica. The pellets are processed into a form that optimizes their performance in the cement matrix.
Solution Approach 2:
The patent modifies the physical parameters of wood fiber to match the functional properties of microsilica. The pellets are sized and treated to provide appropriate surface area, porosity, and chemical reactivity for bonding with cement. The fiber length and density are controlled to achieve compressive strength enhancement comparable to microsilica at a fraction of the cost.
3Ease of operation
If hardwood fiber is used as additive, then water absorption is minimized and viscosity is maintained, but the fiber must maintain sufficient length to form strong bonds with cement
Solution Approach 1:
The patent carefully controls the physical parameters of the wood fiber pellets, including fiber length, diameter, and porosity. The pellets are designed with sufficient fiber length to provide bonding surface area for strong adhesion to cement, while the controlled porosity and hydrophobic treatment minimize water absorption. The pelletization process creates an optimal balance between fiber length for bonding and compactness for handling.
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 wood-based additive effectively reduces the density of cement slurries without breaking down into constituent components, providing a cost-effective, environmentally safe, and compact solution for drilling applications, maintaining a strong bond with cement and preventing premature dehydration.
Implementation Method 1
the additive consisting essentially of wood fiber and water, wherein the material has a density lower than the density of the cement source
Data Source
AI summary
A wood-based cement additive is formed by mixing high-density pellet particles of various sizes. The additive is to be introduced into a cement source to create a slurry mixture. The density of the mixture of pellet particles is selected to be less than the density of the particular cement type in which the pellet particles are introduced. The pellet particles are formed from sawdust or fiber pressed under high pressure, resulting in brittle pellets. The pellets may then be crumbled and screened into particles of an appropriate size. The particles do not disassociate into their constituent materials when mixed with the cement, and thus maintain their density during use in the cementing process.