Schiff Base Lost-Circulation Material for High-Temperature Reservoirs
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Solution Overview
Problem
Current degradable lost circulation materials fail to effectively plug and remove plugging layers in high-temperature fractured reservoirs due to rapid degradation at high temperatures, insufficient plugging adaptability, and high density, leading to reservoir damage and economic losses.
Innovation Solution
A degradable lost circulation material composed of an epoxidized vanillin Schiff base compound and a composite curing agent, including an anhydride and imidazole curing agents, is developed, which exhibits low density, high compressive strength, and temperature resistance, allowing for effective plugging and removal in high-temperature environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If polylactic acid or polymer resin materials are used as self-degradable lost circulation materials, then the materials can degrade after plugging operation, but they degrade rapidly at high temperature with degradation rate difficult to control and exhibit temperature resistance generally at 130°C or lower
Solution Approach 1:
The patent modifies the chemical composition parameters of the lost circulation material by incorporating heat-resistant polymer components and adjusting the molecular structure to maintain stability at high temperatures while preserving controlled degradation capabilities through chemical composition optimization
Solution Approach 2:
The patent creates a composite lost circulation material system combining multiple polymer components with complementary properties, where the composite structure provides both high-temperature resistance and controlled degradability that neither component could achieve alone
2Ease of repair
If calcium carbonate or acid-soluble alloys are used as acid-soluble lost circulation materials, then the plugging can be removed with acid solution, but they have too-high density and insufficient plugging adaptability
Solution Approach 1:
The patent changes the density parameter of the lost circulation material by selecting low-density polymer components and optimizing the particle size distribution, achieving density values suitable for fractured reservoirs while maintaining acid-soluble properties for easy removal
Solution Approach 2:
The patent applies different material properties to different aspects of the lost circulation material: the polymer matrix provides low density and suspension stability, while incorporated acid-reactive components provide easy removal capability, creating a multi-functional material with locally optimized properties
3Reliability
If a large quantity of lost circulation material is added to form an effective plugging layer, then the loss channels can be plugged, but solid particles and liquid phases enter reservoirs in large quantity and block oil and gas seepage channels
Solution Approach 1:
The patent employs porous or hollow spherical lost circulation material particles that provide high plugging effectiveness through their structure while occupying less volume and reducing the total quantity needed, thereby minimizing the amount of material entering the reservoir and reducing blockage of seepage channels
Solution Approach 2:
The patent uses biodegradable or easily removable lost circulation materials that perform their plugging function temporarily during operation and then degrade or can be easily removed, eliminating the need for large quantities and reducing long-term reservoir damage from accumulated solid particles
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 material demonstrates excellent degradability, suspension stability, and pressure-bearing capacity, ensuring effective plugging and removal of plugging layers in high-temperature fractured reservoirs, reducing sedimentation and maintaining reservoir permeability.
Implementation Method 1
A Schiff base bond in the epoxidized vanillin Schiff base compound could be hydrolyzed under acid/alkali conditions, and thus the degradable lost circulation material could be degraded under acidic and alkaline conditions
Data Source
AI summary
Disclosed are a degradable lost circulation material for protecting oil and gas reservoirs, and a preparation method and use thereof, belonging to the technical field of petrochemicals. The degradable lost circulation material includes an epoxidized vanillin Schiff base compound and a composite curing agent, the composite curing agent including an anhydride curing agent and an imidazole curing agent, wherein the epoxidized vanillin Schiff base compound has a structure shown in formula I.