Fracturing Fluids Using Associative Polymers and Labile Surfactants
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Solution Overview
Problem
Existing fracturing fluids used in oil and gas recovery require high energy for injection due to high viscosity and are prone to polymer degradation under shear, necessitating improved injectability and reduced degradation mechanisms.
Innovation Solution
Incorporation of associative polymers and labile surfactants in fracturing fluids, where the labile surfactants reduce viscosity during injection and degrade post-injection, maintaining fluid injectability and reducing polymer degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high viscosity polymers are used to create effective fracturing fluids, then the fluid can create fractures and increase hydrocarbon exchange interfaces, but the energy required for injection increases significantly
Solution Approach 1:
The patent applies dynamics by making the fluid viscosity changeable over time and space. The fluid is injected with low viscosity to minimize pumping energy, then transforms to high viscosity in situ to maintain fracture effectiveness. This temporal and spatial variation in viscosity resolves the contradiction between injection energy and fracturing effectiveness.
Solution Approach 2:
The patent changes the viscosity parameter of the fracturing fluid from low (during injection) to high (after injection). This is achieved through chemical reactions or phase changes that occur after the fluid enters the reservoir, allowing the fluid to meet different requirements at different stages of the fracturing process.
2Reliability
If high viscosity polymers are used to ensure fracturing effectiveness, then the fluid can maintain fracture structure, but the polymers degrade under shear during injection
Solution Approach 1:
The patent makes the polymer structure dynamic rather than static. The polymers remain stable during injection (resisting shear degradation) and then activate or assemble into effective structures after injection. This temporal separation of stability and effectiveness resolves the contradiction between polymer stability and fracturing effectiveness.
Solution Approach 2:
The patent prepares the polymer system in advance to be stable during injection, then triggers the effectiveness mechanism after injection. The polymers are designed to assemble or activate under specific conditions present in the reservoir environment, ensuring they don't degrade during the injection phase but become effective in the fracture phase.
3Reliability
If associative polymers are used to increase viscosity, then the fluid can gel and maintain fracture structure, but the viscosity is too high during injection
Solution Approach 1:
The patent applies dynamics by making the associative polymer system switchable between dispersed (low viscosity) and associated (high viscosity) states. During injection, the polymers remain dispersed for easy pumping; after injection, they associate to form gels that maintain fracture structure. This resolves the contradiction between injectability and fracture structure maintenance.
Solution Approach 2:
The patent changes the association parameter of the polymers from unassociated (during injection) to associated (after injection). This transformation is triggered by environmental conditions in the reservoir or by adding triggers, allowing the fluid to transition from an easily injectable state to a structure-maintaining state.
Data Source
AI summary
The present invention relates to a fracturing fluid comprising, in an aqueous medium: - an associative polymer; and - a labile surfactant in sufficient amount to reduce or inhibit the viscosity-increasing effect induced by said associative polymer.