Thermally Responsive Hydrogels for High-Temperature Viscosity Control
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Solution Overview
Problem
Existing viscosifiers used in subterranean treatments face challenges in maintaining viscosity at high temperatures, particularly in drilling fluids, where polymeric viscosifiers like guar gums struggle, and clay additives can damage formations.
Innovation Solution
The use of thermally responsive hydrogels, which include thermoresponsive polymers that undergo a reversible thickening transition at specific temperatures, providing enhanced viscosity in aqueous-based fluids without chemical reactions, thus maintaining or increasing viscosity at high temperatures and reducing the need for clay materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polymeric viscosifiers are used to maintain viscosity in treatment fluids, then viscosity is improved, but at high temperatures the viscosity control becomes difficult and polymeric viscosifiers alone are insufficient
Solution Approach 1:
The patent combines polymeric viscosifiers with clay materials to create a composite viscosity control system. The polymer provides baseline viscosity while the clay material (such as attapulgite, bentonite, or sepiolite) activates at high temperatures to maintain viscosity when polymeric viscosifiers become insufficient. This composite approach leverages the complementary temperature-dependent behaviors of both materials.
Solution Approach 2:
The patent utilizes temperature as a parameter change to activate different viscosity control mechanisms. At lower temperatures, polymeric viscosifiers dominate viscosity control. As temperature increases, the clay materials become activated and take over viscosity maintenance, providing a progressive, temperature-adaptive viscosity control system that automatically adjusts based on thermal conditions.
2Temperature
If clay material is added to increase viscosity at high temperatures, then viscosity is improved, but formation damage occurs
Solution Approach 1:
The patent applies clay materials selectively in specific zones where high-temperature viscosity control is needed, rather than uniformly throughout the entire treatment fluid system. By controlling the distribution and concentration of clay materials locally, the system achieves necessary viscosity in high-temperature regions while minimizing formation damage in sensitive zones.
Solution Approach 2:
The patent uses clay materials at optimized, partial concentrations that provide sufficient viscosity support at high temperatures without excessive amounts that would cause formation damage. The clay content is carefully controlled to be just enough to maintain viscosity reliability but below the threshold that would cause harmful formation damage.
3Productivity
If viscosity is maintained high for particulate transport, then transport capability is improved, but fluid recovery becomes more difficult
Solution Approach 1:
The patent creates a dynamic viscosity system that changes with temperature. During injection and transport operations, the high temperature downhole activates clay materials to maintain high viscosity for effective particulate transport. During recovery operations at surface conditions, the lower temperature causes the clay materials to become less active, reducing viscosity and making fluid recovery easier. This dynamic, temperature-dependent behavior automatically optimizes both transport and recovery phases.
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 thermally responsive hydrogels effectively thicken fluids at high temperatures, improving particulate transport and reducing fluid loss, while being reversible, thus avoiding damage to formations and allowing for tunable viscosity control.
Implementation Method 1
the thermoresponsive polymer undergoes a reversible thickening transition at about, or above, a thickening transition temperature
Implementation Method 2
thermally responsive hydrogels, which include thermoresponsive polymers that undergo a reversible thickening transition at specific temperatures, providing enhanced viscosity in aqueous-based fluids without chemical reactions
Data Source
AI summary
Methods for the use of treatment fluids that include thermally responsive viscosifiers in subterranean formations are provided. In one embodiment, the methods include introducing a treatment fluid including an aqueous base fluid and a thermally responsive hydrogel including at least one thermoresponsive polymer into at least a portion of a subterranean formation; allowing the thermally responsive hydrogel to reach a thickening transition temperature, wherein the thermally responsive hydrogel undergoes a liquid-to-solid phase change at or above the thickening transition temperature; and allowing the treatment fluid to at least partially solidify in the subterranean formation, wherein the solid thermally responsive hydrogel is present in the treatment fluid in an amount from about 0.01 to about 0.2 by volume fraction of solids of the treatment fluid.