In Situ Foamed Cement for Loss Circulation Control
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Solution Overview
Problem
Current loss circulation treatments in wellbores face challenges in accurately addressing the dimensions and shapes of loss circulation zones, leading to inefficiencies and significant revenue losses due to fluid loss, as existing solutions are not adaptable to varying sizes and shapes of thief zones.
Innovation Solution
A non-hydraulic, foamed cementitious composition comprising magnesium oxide, a salt (such as magnesium chloride or sulfate), azodicarbonamide as a nitrogen gas-generating compound, carbohydrazide, and a foam surfactant, which forms a hard mass upon placement to fill and seal loss circulation zones effectively, regardless of their shape or size, without requiring extensive foam equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional loss circulation treatment materials are used, then fluid loss can be reduced in some zones, but they cannot adapt to varying sizes and shapes of thief zones leading to treatment inefficiency
Solution Approach 1:
The cement composition transitions from a fluid slurry state during injection to a solidified hard mass after placement, dynamically adapting its physical state to fill and seal thief zones of varying sizes and shapes. This phase change enables the material to conform to any loss circulation zone geometry while maintaining structural integrity for effective sealing.
Solution Approach 2:
The composition utilizes controllable setting time parameters and foam expansion ratios to adapt to different thief zone dimensions. By adjusting the foam-to-cement ratio and setting time, the treatment can be optimized for microfractures or large vugular zones, providing versatility across different loss circulation scenarios.
2Adaptability or versatility
If foam equipment is used to create expandable foam treatments, then adaptability to thief zones improves, but equipment complexity and cost increase
Solution Approach 1:
The composition generates its own foam structure through in-situ chemical reaction between the salt and water, eliminating the need for external foam generation equipment. The salt-water reaction produces foam bubbles that expand the cement slurry, allowing the material to self-foam and adapt to thief zone geometries without requiring complex foam generation systems.
Solution Approach 2:
The patent replaces mechanical foam generation systems with a chemical foam generation mechanism. Instead of using mechanical foamers or pressurized foam equipment, the foam is generated through the chemical reaction between salt and water, substituting a complex mechanical system with a simpler chemical process.
3Strength
If hydraulic cement is used for loss circulation control, then setting strength is achieved, but water sensitivity and solubility problems occur
Solution Approach 1:
The composition creates a composite material system combining salt, water, foam, and cementitious components that together produce a water-stable, strong solid mass. The salt-water reaction products form a composite structure with the cement and foam, resulting in a material that achieves both strength and water stability, overcoming the limitations of conventional hydraulic cements in water-sensitive zones.
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 composition effectively forms a hard, stable seal within the wellbore to withstand hydrostatic pressures, reducing fluid loss and improving the adaptability of loss circulation treatments, thereby minimizing revenue losses and operational challenges.
Implementation Method 1
azodicarbonamide as a nitrogen gas-generating compound
Implementation Method 2
Settable, non-hydraulic foamed cement compositions... forms a hard mass upon placement
Data Source
Figure 1~2
AI summary
This document relates to settable, non-hydraulic foamed cement compositions comprising nitrogen gas-generating compositions used for loss circulation control.