Polyacetal Compositions for Subterranean Degradation
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Solution Overview
Problem
Conventional degradable materials for subterranean formations, such as polylactic acid and polyhydroxyalkanoates, are not suitable for heavy brine environments, have variable degradation rates, and do not release a strong acid upon hydrolysis, limiting their effectiveness in certain applications.
Innovation Solution
Inducibly degradable compositions comprising polyacetal that can degrade in a controlled manner in the presence of sulfur dioxide or strong acids, forming a strong acid and being stable across a broader temperature range, including deep-water wells from 120° F to 320° F.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional degradable materials (polylactic acid, polyhydroxyalkanoates) are used, then the materials can degrade by hydrolyzing in aqueous environments, but the degradation rate varies based on temperature, time, crystallinity, pH, and salinity making them unsuitable for heavy brine environments
Solution Approach 1:
The patent changes the chemical composition parameter from conventional hydrolyzable polymers to polyacetal, which fundamentally alters the degradation mechanism from hydrolysis to oxidation. This parameter change enables the material to be insensitive to pH, salinity, and temperature variations, providing reliable degradation in heavy brine environments where conventional materials fail.
Solution Approach 2:
The patent employs composite material strategy by combining polyacetal with metal oxides (such as iron oxide, copper oxide, or manganese oxide) to create a composite degradable material. The metal oxide component catalyzes the oxidation degradation of polyacetal, enabling controlled degradation in subterranean formations while maintaining stability during the service life of the material.
2Object-generated harmful factors
If conventional degradable materials are used, then the materials can provide temporary functionality, but they do not release a strong acid when they hydrolyze limiting their effectiveness in certain applications
Solution Approach 1:
The patent extracts the acid-generating function from the degradation process itself by incorporating metal oxide particles that can generate strong acids (such as sulfuric acid from iron oxide) during oxidation degradation. This separates the structural function of polyacetal from the acid-generating function of metal oxides, enabling controlled strong acid release for remediation applications.
Solution Approach 2:
The patent converts the potentially harmful oxidation degradation process into a beneficial acid-generating mechanism. The oxidation of polyacetal in the presence of metal oxides generates strong acids that can be utilized for remediation purposes, such as stimulating hydrocarbon production or dissolving scale, thereby turning the degradation 'harm' into a useful 'blessing'.
3Duration of action of stationary object
If degradable materials are placed in subterranean formations for temporary functionality, then the materials can perform required functions, but once functionality is no longer required the materials must degrade which may not occur reliably in certain environments
Solution Approach 1:
The patent introduces dynamic control over the degradation process by incorporating metal oxide catalysts that can be activated at specific times or conditions. The polyacetal material remains stable during the service life but degrades reliably when exposed to conditions that activate the metal oxide catalyst, such as presence of water or specific temperature ranges, thus providing both long service duration and reliable end-of-life degradation.
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 polyacetal compositions provide controlled degradation, compatibility in heavy brine environments, and the ability to form strong acids, enhancing their suitability for various subterranean applications, including completion fluids and equipment, by degrading into aqueous soluble materials post-use.
Implementation Method 1
In certain embodiments, the polyacetal may degrade in the presence of an oxidizer to form a strong acid
Implementation Method 2
degrade in the presence of sulfur dioxide or strong acids
Data Source
AI summary
Inducibly degradable compositions comprising polyacetal and associated methods and systems.