Cross-linked Polysaccharide LCMs for High-Temp Wellbore Sealing
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Solution Overview
Problem
Conventional plugging materials fail to effectively seal permeable zones in wellbores at temperatures above 230° F., leading to fluid loss and compromised cement strength, which delays drilling and cementing operations.
Innovation Solution
The use of cross-linked polysaccharides as lost circulation materials (LCMs) that break crosslinking bonds at around 160° F.-170° F., allowing the material to maintain effectiveness at higher temperatures by increasing thickening time and gel strength without impacting surface mixing, and including additives like hydraulic cement, amorphous silica, and retarders to enhance sealing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional plugging materials are used at temperatures above 230° F., then the sealing capability deteriorates, but using alternative materials may compromise other fluid properties
Solution Approach 1:
The patent changes the chemical parameters of the plugging material by using cross-linked polysaccharides with specific bond breaking temperatures (160° F.-170° F.). This allows the material to maintain stability during surface operations and then transform at downhole temperatures above 230° F., achieving reliable sealing without compromising other fluid properties throughout the operation
Solution Approach 2:
The patent employs composite material composition combining cross-linked polysaccharides with hydraulic cement, amorphous silica, and retarders. This composite structure provides both high-temperature sealing capability and maintains appropriate fluid properties for circulation and placement, resolving the contradiction between reliability and adaptability
2Reliability
If cross-linked polysaccharides are used to maintain effectiveness at high temperatures, then thickening time and gel strength increase, but this may impact surface mixing operations
Solution Approach 1:
The cross-linked polysaccharide material exhibits dynamic properties where the cross-linking bonds remain intact during surface mixing and handling, providing workable fluid characteristics. Upon exposure to downhole temperatures above 230° F., the bonds break dynamically, triggering gel strength build-up and sealing action. This dynamic behavior resolves the contradiction between high-temperature effectiveness and ease of surface manufacturing
Solution Approach 2:
The material undergoes parameter changes based on temperature: at surface conditions, the cross-linked structure maintains fluidity for easy mixing; at downhole temperatures above 230° F., the cross-linking bonds break (at 160° F.-170° F.), increasing gel strength and thickening time to provide effective sealing
3Reliability
If plugging materials are used to seal permeable zones, then fluid loss is prevented, but drilling and cementing operations are delayed
Solution Approach 1:
The cross-linked polysaccharide plugging material is designed to act preliminarily by maintaining stability during surface operations and initial circulation, then automatically activating at downhole temperatures above 230° F. to seal permeable zones. This preliminary positioning without immediate activation prevents fluid loss while avoiding operation delays, as the material is already in place and ready to seal when temperature conditions are met
Solution Approach 2:
The material utilizes phase transition triggered by temperature: the cross-linked polysaccharide remains in a fluid, pumpable state during surface operations, then transitions to a gelated, sealing state when exposed to downhole temperatures above 230° F. This phase transition mechanism provides fluid loss prevention without requiring additional time for material placement or activation procedures
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 cross-linked polysaccharide-based LCMs achieve compressive strengths over 100 psi at 340° F., rapid gel strength build-up, and extended thickening times, effectively sealing permeable zones and preventing fluid loss, even at high temperatures, thus enhancing wellbore operations.
Implementation Method 1
cross-linked polysaccharides that break crosslinking bonds at around 160° F.-170° F.
Implementation Method 2
rapid gel strength build-up
Implementation Method 3
extended thickening times
Implementation Method 4
compressive strengths over 100 psi at 340° F.
Data Source
AI summary
Described herein are plugging materials with polysaccharides that can be used in wellbore operations. A plugging material can include hydraulic cement, amorphous silica, polysaccharides, a retarder, clay, and an aqueous base, where the material is injectable into a wellbore. The polysaccharides can be cross-linked with borate. The retarder can be at least one of an organo phosphoric acid, a modified sulfonated styrene-maleic anhydride polymer, lignosulfonate, or a polyacrylic acid.