Aliphatic Polyester Molded Product for Downhole Tools
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Solution Overview
Problem
There is a need for a molded product with an aliphatic polyester resin that has an effective thickness of 1 mm or more, exhibiting excellent degradability in low-temperature downhole environments, such as those below 66°C, and sufficient mechanical strength for rapid degradation in hydrocarbon resource recovery applications.
Innovation Solution
A molded product is formed using an aliphatic polyester resin composition containing 1 to 30 parts by mass of a carboxylic acid anhydride per 100 parts by mass of polyglycolic acid resin, combined with short fiber reinforcing materials, thermoplastic elastomers, or acrylic rubber core-shell polymers, to achieve an effective thickness of 1 mm or more, ensuring rapid degradation and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the molded product is increased to 1 mm or more for practical applications, then the mechanical strength and structural integrity are improved, but the degradation time becomes excessively long even in downhole environments
Solution Approach 1:
The patent changes the chemical composition parameters of the polyester resin by incorporating specific ratios of glycolic acid units (50-100 mass%) and caprolactone units (0-50 mass%), along with controlled molecular weight (10,000-1,000,000) and crystallinity (30-80%). These parameter adjustments enable the resin to maintain mechanical strength while achieving rapid degradation within 7 days even at thicknesses of 1 mm or more.
Solution Approach 2:
The patent creates a composite polyester resin system combining multiple components: glycolic acid polymer chains providing strength, caprolactone segments enhancing degradability, and controlled crystallinity regions. This composite molecular structure allows simultaneous achievement of mechanical integrity and rapid biodegradation in downhole environments.
2Duration of action of stationary object
If the degradation rate is increased for rapid breakdown in low-temperature environments, then the environmental friendliness and ease of disposal are improved, but the mechanical strength and structural integrity deteriorate
Solution Approach 1:
The patent optimizes the molecular weight parameter to 10,000-1,000,000 and controls the ratio of glycolic acid to caprolactone units, along with maintaining crystallinity between 30-80%. These parameter settings create a balance where the material degrades rapidly (within 7 days) while retaining sufficient mechanical strength for downhole tool applications.
Solution Approach 2:
The patent creates regions of different crystallinity within the polyester resin structure, where crystalline regions provide mechanical strength and amorphous regions facilitate degradation. This local differentiation of material properties allows simultaneous achievement of strength and rapid degradability.
3Strength
If the crystallinity of the polyester resin is increased to improve mechanical strength and heat resistance, then the structural integrity is improved, but the degradation rate decreases
Solution Approach 1:
The patent maintains crystallinity within the specific range of 30-80% rather than maximizing it. This optimized crystallinity level, combined with controlled molecular weight and compositional ratios, allows the material to achieve sufficient mechanical strength while preserving adequate degradation rate for practical applications.
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 solution provides a molded product with enhanced degradability and mechanical strength, allowing for efficient and economical well drilling operations by ensuring the molded product can degrade quickly in low-temperature environments, maintaining sufficient mechanical properties for practical use.
Implementation Method 1
a molded product having an effective thickness of 1 mm or more, the molded product being formed from an aliphatic polyester resin composition containing from 1 to 30 parts by mass of a carboxylic acid anhydride per 100 parts by mass of an aliphatic polyester resin containing not less than 50 mass % of a polyglycolic acid resin
Implementation Method 2
Since aliphatic polyester resins such as polyglycolic acid resins (sometimes called a "PGA" hereafter) or polylactic acid resins (sometimes called "PLA" hereafter) are degraded by microorganisms or enzymes existing in the natural world such as in soil or in oceans
Data Source
AI summary
Described are a molded product having an effective thickness of 1 mm or more, the molded product being formed from an aliphatic polyester resin composition containing from 1 to 30 parts by mass of a carboxylic acid anhydride and preferably further containing from 1 to 50 parts by mass of at least one type of a short fiber reinforcing material, a thermoplastic elastomer, or an acrylic rubber core-shell polymer per 100 parts by mass of an aliphatic polyester resin containing not less than 50 mass % of a polyglycolic acid resin, the effective thickness being 1 mm or more; a downhole tool for hydrocarbon resource recovery formed from the molded product having an effective thickness of 1 mm or more; an aliphatic polyester resin composition for the downhole tool member for hydrocarbon resource recovery; and a well drilling method.