Methane Hydrate Production via CO2 Dispersed Water Injection
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Solution Overview
Problem
Current methods for producing methane gas from methane hydrate layers, such as heating and decompression, face economic challenges and environmental concerns like waste water treatment and land subsidence, while CO2 injection methods are not yet commercially viable for wide-area production.
Innovation Solution
A methane gas production facility with a first horizontal well for injecting CO2-dispersed water into a methane hydrate layer and a second horizontal well for decompressing and separating the released methane gas, utilizing a carbon dioxide dispersion unit to create supercritical CO2 dispersion for efficient gas release and separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heating method is used to decompose methane hydrate, then methane gas can be produced, but it is difficult to widely heat a methane hydrate layer from an economic viewpoint
Solution Approach 1:
The patent divides the heating process into two parts: a heating well that supplies heat and a production well that extracts gas. This segmentation allows targeted heating only in the vicinity of the heating well, reducing the overall energy required to heat large areas of the methane hydrate layer.
Solution Approach 2:
The patent introduces water as an intermediary heat transfer medium. Hot water or steam is injected through the heating well to transfer thermal energy to the methane hydrate layer, avoiding the need for direct heating equipment in the formation and reducing energy costs.
2Productivity
If decompression method is used to produce methane gas, then production is more economically excellent, but a large amount of water generated during decomposition must be pumped
Solution Approach 1:
The patent combines the decompression method with thermal stimulation by injecting hot water. This merging allows methane gas to be produced through decompression while the hot water serves dual purposes: providing heat to accelerate decomposition and facilitating gas extraction through the same production well.
Solution Approach 2:
The water injected into the formation serves multiple functions simultaneously: it acts as a heat carrier, a decompression medium, and the extraction fluid for methane gas. This self-service approach reduces the need for separate systems for heating, decompression, and water management.
3Reliability
If CO2 injection method is used to release methane gas, then hydrate layer can receive CO2 in stable state, but the technology is not commercialized yet for wide-area production
Solution Approach 1:
The patent changes the physical state parameters of CO2 by injecting it as supercritical fluid or fine bubbles rather than gaseous CO2. This parameter change enhances CO2 solubility in the injected water, improving its ability to replace methane in the hydrate structure and enabling wider area application.
Solution Approach 2:
The patent uses hydraulic injection of CO2-saturated water or supercritical CO2 into the formation. This hydraulic approach allows controlled delivery of CO2 to the methane hydrate layer, enabling reliable CO2-ch hydrate formation while maintaining productivity through adjustable injection rates and pressures.
4Area of stationary object
If horizontal wells are used for wide-area production, then production area increases, but device complexity increases
Solution Approach 1:
The patent segments the wide-area production system into multiple independent well pairs, each consisting of a heating well and a production well. This segmentation allows each pair to operate autonomously, simplifying individual well design while achieving wide-area coverage through replication of the basic unit.
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
This approach enables efficient methane gas production over a wide area by combining CO2 replacement and decompression methods, reducing environmental impact and operational costs, and allowing for effective gas-liquid separation.
Implementation Method 1
injection water obtained by dispersing a carbon dioxide gas in water
Implementation Method 2
a decompression and suction unit which decompresses an inside of the second horizontal well by pumping water
Implementation Method 3
a gas-liquid separation unit which separates a methane gas from water sucked using the decompression and suction unit
Data Source
AI summary
A methane gas production facility or the like capable of efficiently producing a methane gas from a wide range of a methane hydrate layer. In a methane gas production facility that produces a methane gas from a methane hydrate layer MHL, a first horizontal well is provided along the methane hydrate layer MHL and injection water supply units supply injection water obtained by dispersing a carbon dioxide gas in water to the first horizontal well. A second horizontal well is provided along an area in which methane released from methane hydrate by replacement with carbon dioxide rises, a decompression and suction unit decompresses the inside of the second horizontal well by pumping water and sucks water containing methane, and a gas-liquid separation unit separates a methane gas from the sucked water.