Stimuli-Responsive High Viscosity Pill for Subterranean Fluid Control
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Solution Overview
Problem
Conventional cross-linked gelling agents used in subterranean operations are difficult to remove from formations after treatment, leading to reduced formation permeability and increased cleanup time, often requiring costly and hazardous methods.
Innovation Solution
The use of stimuli-responsive treatment fluids comprising an aqueous base fluid, a viscoelastic surfactant, and a stimuli-degradable polymer that changes viscosity in response to temperature, pH, or contact with oleaginous fluids, allowing for controlled breakdown and potential acid generation to degrade fluid loss control agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cross-linked gelling agents are used to form high viscosity pills, then fluid-loss control and solids support are improved, but gel residue removal becomes difficult and formation permeability is reduced
Solution Approach 1:
The gel structure is segmented into degradable components through incorporation of hydrolyzable bonds (ester, amide, carbamate linkages) that can be broken down by environmental conditions or additives, allowing the gel to be divided into removable smaller molecules after serving its function
Solution Approach 2:
Cross-linking agents with hydrolyzable bonds act as intermediaries that provide the necessary cross-linking for gel strength while containing built-in degradation pathways that allow breakdown into water-soluble or dispersible fragments for easier removal
2Reliability
If cross-linked gels are used to support solids and control fluid loss, then pill effectiveness is improved, but cleanup time and cost increase
Solution Approach 1:
The gel system transitions from a static cross-linked structure to a dynamic system that can degrade and change its properties over time in response to environmental conditions (pH, temperature) or added triggers, allowing it to break down when cleanup is needed
Solution Approach 2:
The gel's chemical structure incorporates parameter-sensitive bonds (ester, amide, carbamate) that change their stability based on pH, temperature, or enzymatic conditions, allowing the gel to maintain strength during operation but break down under cleanup conditions
3Ease of operation
If strong acid is used to clean up gel residue, then gel removal is improved, but safety hazards and equipment cost increase
Solution Approach 1:
The gel is designed as a temporary structure with built-in degradation capability, replacing the need for expensive and hazardous strong acid cleanup with a self-degrading or easily degradable system that breaks down into harmless water-soluble fragments
Solution Approach 2:
The cross-linking bonds that provide gel strength are designed to be hydrolyzable, converting what would normally be permanent structural bonds into temporary ones that can be broken down by mild conditions, turning a potential cleanup problem into an automatic breakdown feature
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
This approach enables efficient cleanup of gel residues without the need for separate breakers, reduces cleanup time, and minimizes the use of costly equipment, while maintaining formation permeability and safety.
Implementation Method 1
a stimuli-responsive treatment fluid that changes viscosity in response to temperature
Implementation Method 2
the acid generating group comprises a monomer or polymer selected from the group consisting of: an ester, an ortho ether, a poly(ortho ether), an aliphatic polyester, a lactide, a poly(lactide), a glycolide, a poly(glycolide), a lactone, a poly(ε-caprolactone), a poly(hydroxybutyrate), an anhydride, a poly(anhydride), a poly(amino acid), and any combination thereof
Data Source
AI summary
A method comprises providing a treatment fluid having a first viscosity comprising an aqueous base fluid; a viscoelastic surfactant; and a stimuli-responsive water-soluble polymer; introducing the treatment fluid into a subterranean formation; and allowing the treatment fluid viscosity to change to a second viscosity in response to a stimulus.