High Temperature Polymer Gel Crosslinking System
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Solution Overview
Problem
High temperature organic crosslinking agents used in polymer gels for subterranean formations either gel too rapidly or too slowly, making it difficult to achieve an optimal gel time for effective treatment in high temperature environments.
Innovation Solution
A composition using a crosslinking system comprising a primary dialdehyde benzene source, a secondary low temperature organic crosslinking agent that generates aldehyde, and a phenol source, providing a delayed gel time of 2 to 20 hours at temperatures above 250°F (121°C), optimized by adjusting the amounts of dialdehyde benzene, hexamethylenetetramine, and phenyl acetate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high temperature organic crosslinking agents are used, then the polymer gels can be formed in high temperature subterranean formations, but the gel time becomes either too short or too long to allow proper injection and placement
Solution Approach 1:
The crosslinking system is divided into multiple components: a polymer component containing dialdehyde groups, a phenolic component, and a catalyst component. These components are mixed in sequence rather than all at once, allowing control over the crosslinking reaction rate and gel time while maintaining effectiveness at high temperatures up to 350°F
Solution Approach 2:
The polymer is pre-modified with dialdehyde groups before injection, and the phenolic component is prepared in advance. The actual crosslinking reaction is initiated only after the polymer solution is injected into the formation, allowing proper placement before gelation begins. This preliminary preparation enables controlled timing of the crosslinking action
2Reliability
If crosslinking agents are used to form polymer gels for shutting off water or gas, then the desired zones can be sealed, but the gelation occurs too rapidly to facilitate proper injection and placement
Solution Approach 1:
The system transitions from a static pre-mixed approach to a dynamic sequential mixing approach. The polymer solution is injected first in its un-crosslinked fluid state, allowing easy injection and placement. The crosslinking reaction is then initiated in-situ, transforming the fluid into a gel structure that provides the desired shut-off effectiveness
Solution Approach 2:
The catalyst component acts as an intermediary that controls the timing and rate of the crosslinking reaction. By adding the catalyst after polymer injection but before complete placement, the system mediates between the need for easy injection (uncrosslinked state) and effective shut-off (crosslinked gel state), enabling controlled transition between these states
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 achieves a controlled gel time that is neither too short nor too long, allowing for effective treatment of subterranean formations by maintaining stability and allowing proper placement of polymer fluids in high temperature environments.
Implementation Method 1
Water-soluble polymers are typically employed that are introduced into a formation and are subsequently crosslinked so that the polymers gel
Implementation Method 2
Metal crosslinking agents have been used in certain situations to crosslink polymers to form polymer gels
Implementation Method 3
a secondary low temperature organic crosslinking agent that generates aldehyde
Data Source
AI summary
A composition for treating a subterranean formation is formed from water, a water-soluble polymer and a crosslinking system. The crosslinking system utilizes 1) primary crosslinking agent of at least one of a dialdehyde benzene source, a dioxane, and a trioxane, 2) a secondary low temperature organic crosslinking agent that generates aldehyde, and 3) a phenol source. The crosslinking system provides the composition a delayed gel time of about 2 to about 20 hours at temperatures of about 250° F. (121° C.) or higher. A method of treating a subterranean formation penetrated by a wellbore is also accomplished by forming a treatment fluid from the composition and introducing the treatment fluid into the formation through the wellbore.