Plant-Based Gel Diverting Agent for Oilfield Fracturing
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Solution Overview
Problem
Current liquid gel temporary plugging agents for oilfield fracturing face issues with non-environmentally friendly materials, low applicable temperature, and difficulty in breaking the gel, which complicates the fracturing process and may damage the reservoir.
Innovation Solution
A plant-based self-degradable gel diverting agent is developed using urea-formaldehyde resin and starch, with a preparation method involving pH adjustments and curing processes to achieve high strength, degradability, and wide temperature applicability, ensuring minimal reservoir damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If liquid gel temporary plugging agents are used for fracturing diversion, then the injection is simple and the gel can be broken after construction, but the applicable temperature range is limited and the gel is difficult to break at high temperatures
Solution Approach 1:
The patent modifies the chemical composition parameters of the gel system by incorporating amino acids as crosslinking agents and adjusting the monomer ratios, which enables the gel to maintain its breaking capability across a wider temperature range while preserving easy injection properties
Solution Approach 2:
The patent creates a composite gel system combining multiple components including acrylic acid, acrylamide, amino acid crosslinking agents, and initiators, which synergistically provide both easy injection and extended temperature applicability with improved gel breaking performance
2Strength
If conventional gel temporary plugging agents are used, then the plugging strength is sufficient, but the materials are non-environmentally friendly and cause reservoir damage
Solution Approach 1:
The patent changes the chemical composition parameters by replacing conventional synthetic crosslinking agents with amino acid-based crosslinking agents, maintaining plugging strength while eliminating environmental harm and reservoir damage through biodegradable materials
Solution Approach 2:
The patent employs biodegradable amino acid crosslinking agents that temporarily provide structural strength during the fracturing operation but naturally decompose afterward, serving their purpose temporarily without leaving harmful residues in the reservoir
3Speed
If the gel cross-links quickly under reservoir conditions, then the plugging effect is achieved rapidly, but the gelling time is too short for proper injection and distribution
Solution Approach 1:
The patent introduces dynamic control of the cross-linking process through conditional initiation - the gel remains liquid during injection due to stable monomer-prepolymer composition, then rapidly cross-links upon contact with reservoir conditions, achieving both injectability and rapid plugging
Solution Approach 2:
The patent performs preliminary preparation of prepolymers and monomers with controlled molecular weights and compositions before injection, which then rapidly cross-link under reservoir conditions, achieving rapid gelling after distribution without requiring extended gelling time
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 plant-based gel diverting agent exhibits high compressive strength, excellent plugging performance, and self-degradability, with a wide temperature range and low environmental impact, enhancing oil and gas recovery while minimizing reservoir harm.
Implementation Method 1
After injection, the liquid gel temporary plugging agent cross-links under the reservoir condition to form a high-strength rubber plug
Implementation Method 2
the rubber plug reacts with a gel breaker or self-degrades to form small molecules that flow back to the surface
Implementation Method 3
the rubber plug reacts with a gel breaker or self-degrades to form small molecules
Data Source
AI summary
The present invention discloses a plant-based self-degradable gel diverting agent and a preparation method therefor. The preparation method comprises the following steps: adjusting a pH of a formaldehyde solution, adding urea in three batches, heating and stirring, adding furfural in the process of adding a second batch of urea until a plant-based urea-formaldehyde resin is obtained through the reaction, completely dissolving starch in water, uniformly stirring to obtain a gelatinized starch solution, adding the plant-based urea-formaldehyde resin, adding a curing agent, and uniformly stirring, mixing and curing to obtain a product. The resin plugging agent is a liquid homogeneous system and has a low initial viscosity; the system is particle-free, can enter tiny slits; and the gel temporary plugging agent does not need to be added with a gel breaker at a temperature of 100-180° C., the temporary plugging agent can be completely degraded.