Geopolymer Well Cement Slurry Density Without Viscosity Drift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing well cementing technologies face challenges in controlling slurry viscosity, thickening time, and density without altering the fluid-to-solids ratio, leading to issues like fluid loss and cementing failures in subterranean applications.
Innovation Solution
The use of geopolymer compositions comprising aluminosilicate sources, metal silicates, alkali or alkaline earth activators, and slurry density modifiers like unitatite, vitrified shale, or petroleum coke, along with additives to control viscosity, thickening time, and density, ensuring pumpability and effective zonal isolation in subterranean wells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fluid-to-solids ratio of geopolymer slurry is adjusted to control viscosity and thickening time, then the slurry flowability and setting characteristics are improved, but the slurry density changes which affects placement and zonal isolation performance
Solution Approach 1:
The patent introduces density modifiers (barite, hematite, magnetite, ilmenite, or calcite) that allow independent adjustment of slurry density without changing the fluid-to-solids ratio. This enables separate control of density parameter from viscosity and thickening time parameters, resolving the contradiction between ease of operation and quantity of substance.
Solution Approach 2:
The patent creates a composite slurry system combining geopolymer binder, density modifiers, and optional additives. This composite approach allows tuning of multiple properties simultaneously - the density modifiers adjust density while the geopolymer matrix maintains viscosity and thickening characteristics, enabling independent optimization of each parameter.
2Quantity of substance
If density modifiers are added to adjust slurry density, then the slurry density and zonal isolation capability are improved, but the slurry viscosity increases which may affect pumpability
Solution Approach 1:
The patent specifies that density modifiers are added in controlled amounts (0-20% by weight of total slurry) to adjust density while monitoring viscosity changes. This parameter control approach allows achieving target density while maintaining pumpability by adjusting other slurry composition parameters compensatorily.
Solution Approach 2:
The patent employs water-soluble viscosity modifiers or dispersants as intermediaries to manage the viscosity increase caused by density modifiers. These additives mediate between the density modification requirement and the pumpability requirement, allowing density adjustment without excessive viscosity penalty.
3Reliability
If the geopolymer slurry is designed for rapid setting and hardening, then the zonal isolation effectiveness is improved, but the placement time window is reduced which may complicate the cementing operation
Solution Approach 1:
The patent incorporates retarders or accelerators as preliminary actions to control the setting rate. By adding small amounts of these chemical additives, the setting time can be extended during placement operations and then accelerated after placement, allowing both adequate placement time window and rapid final set for effective zonal isolation.
Solution Approach 2:
The patent designs the geopolymer system to exhibit time-dependent property changes - initially pumpable and placeable, then progressively setting and hardening. This periodic action pattern provides a natural placement window followed by rapid strength gain, resolving the contradiction between placement time and isolation effectiveness.
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 geopolymer compositions provide adjustable slurry densities and controlled thickening times, enhancing the success of well cementing operations by preventing fluid loss and ensuring robust zonal isolation in varying underground conditions.
Implementation Method 1
Geopolymers are a novel class of materials that are formed by chemical dissolution and subsequent recondensation of various aluminosilicate oxides and silicates to form an amorphous three-dimensional framework structure
Implementation Method 2
The geopolymer precursor slurry may have a density between about 0.89 g/cm3 (7 lbm/gal) and 2.87 g/cm3 (24 lbm/gal), inclusive. The slurry density can be adjusted by adding various materials including uintatite, vitrified shale, petroleum coke, or coal
Implementation Method 3
The suspension of solid raw materials into a carrier fluid to form a slurry... an alkali or alkaline earth activator
Data Source
AI summary
Geopolymeric compositions are presented that are useful for cementing subterranean wells. The compositions may contain an aluminosilicate source, a metal silicate, an alkali activator and a slurry density modifier that may contain uintaite, vitrified shale, petroleum coke or coal or combinations thereof. Methods for placing the geopolymeric compositions in subterranean wells are also presented.