Water-absorbable Resin Shrinking via Iron Ion Crosslinking
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Solution Overview
Problem
Current methods for hydraulic fracturing in shale gas/oil mining face challenges in effectively decomposing water-absorbable resins used in fracturing fluids and in providing suitable shrinking agents for proppants, which affect the stability and efficiency of fracture maintenance.
Innovation Solution
The use of iron-ion-containing substances, ascorbic acid, and persulfate salts as breaking agents for water-absorbable resins, and multivalent metal-ion-containing substances as shrinking agents, which facilitate the liquefaction and shrinkage of these resins in a water-containing state, respectively, to enhance fracturing fluid efficiency and proppant performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If water-absorbable resin is used as fracturing fluid additive, then fluid viscosity and fracture stability are improved, but resin decomposition and gel strength loss occur over time
Solution Approach 1:
The patent applies preliminary action by incorporating oxidizing agents (persulfate salts, hydrogen peroxide) and metal ions (iron, copper) into the fracturing fluid formulation before injection. These agents remain dormant during the fracturing operation and only activate later to decompose the water-absorbable resin, thereby maintaining fracture stability during the operation while enabling controlled decomposition afterward. This resolves the contradiction by preparing the decomposition mechanism in advance without affecting initial fracture stability.
Solution Approach 2:
The patent uses metal ions (particularly iron ions) and oxidizing agents as intermediary substances that mediate between the water-absorbable resin and decomposition. These intermediaries are introduced into the fracturing fluid and remain stable during injection, then catalyze resin decomposition through oxidation reactions. This intermediary mechanism allows the resin to maintain stability during fracturing while enabling controlled decomposition later, resolving the contradiction between stability and durability.
2Productivity
If breaking agents are added to decompose water-absorbable resin, then resin decomposition is accelerated, but fluid viscosity control and fracture stability are compromised
Solution Approach 1:
The breaking agents (oxidizing agents and metal ions) are incorporated into the fracturing fluid in advance but remain inactive during the fracturing operation. The decomposition reaction is triggered only after the fracturing is complete, allowing high decomposition rates without compromising fracture stability during the operation. This temporal separation resolves the contradiction between decomposition speed and stability.
Solution Approach 2:
The patent utilizes parameter changes by controlling the activation conditions of the breaking agents. The oxidizing agents and metal ions remain stable at the injection conditions (temperature, pressure, pH) but become active under post-fracturing conditions. This parameter-based control enables fast decomposition only when needed, maintaining both high productivity in decomposition and fracture stability during operation.
3Volume of moving object
If multivalent metal ions are used as shrinking agents for proppants, then proppant size reduction is achieved, but proppant strength and fracture support capability are reduced
Solution Approach 1:
The patent applies parameter changes by controlling the concentration and type of multivalent metal ions used for proppant shrinking. By optimizing the metal ion dosage and selecting specific ions (Ca²⁺, Mg²⁺, Al³⁺), the process achieves sufficient proppant size reduction while maintaining adequate strength. The controlled parameter adjustment resolves the contradiction between size reduction and strength preservation.
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
These agents enable efficient decomposition of water-absorbable resins and effective shrinkage of proppants, improving the stability and longevity of fractures, thereby enhancing the extraction efficiency of shale gas/oil.
Implementation Method 1
a breaking agent for a water-absorbable resin used in hydraulic fracturing of a stratum, including: an iron-ion-containing substance and/or ascorbic acid
Implementation Method 2
and/or a persulfate salt
Implementation Method 3
a shrinking agent for a water-absorbable resin used as a proppant in hydraulic fracturing of a stratum, including a metal-ion-containing substance
Data Source
AI summary
The present invention provides a contraction agent for a water-absorbing resin that is used as a proppant in stratum hydraulic fracturing, the contraction agent containing: a metal ion-containing substance and a breaking agent for water-absorbing resins used in stratum hydraulic fracturing; and an iron ion-containing substance and/or ascorbic acid, and/or a persulfate. Also provided is a kit for use in stratum hydraulic fracturing, the kit provided with a swelling agent containing a water-absorbing resin, an iron ion-containing substance, and ascorbic acid, the kit being for stratum hydraulic fracturing, wherein the kit consists of A) a proppant containing a water-absorbing resin, and B) a contraction agent for the water-absorbing resin containing a metal ion-containing substance.