Produced Gas Cooling and Fractionation for Liquid Waste Injection
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Solution Overview
Problem
Current processes for processing produced gases from wells fail to rapidly and ecologically acceptably dispose of unusable gases like carbon dioxide and hydrogen sulfide, often venting them into the atmosphere, which is undesirable due to environmental concerns and economic inefficiencies.
Innovation Solution
A method involving dehydration, cooling, and fractionation of produced gases to separate hydrocarbon gases from waste gases like carbon dioxide and hydrogen sulfide, converting these waste gases into a liquid form for injection into a separate injection well, where they can be disposed of in a controlled manner, enhancing hydrocarbon recovery by pressurizing and directing them into suitable geological formations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If waste gases like carbon dioxide and hydrogen sulfide are vented into the atmosphere, then disposal is simple and rapid, but environmental harm increases and ecological acceptability deteriorates
Solution Approach 1:
The patent converts the harmful waste gases (carbon dioxide and hydrogen sulfide) into a beneficial resource by injecting them back into the geological formation to stimulate hydrocarbon production. The waste gases are pressurized and injected into the formation to maintain pressure and displace additional hydrocarbons toward producing wells, thus transforming an environmental problem into an economic benefit.
Solution Approach 2:
The patent changes the physical state and pressure parameters of the waste gases. The gases are compressed to high pressures (e.g., 3000-5000 psig) and injected into the formation, transforming them from low-pressure atmospheric venting candidates into high-pressure injection media that can effectively stimulate production.
2Manufacturing precision
If produced gas is cooled to separate waste gases, then separation efficiency improves, but energy consumption increases
Solution Approach 1:
The patent merges the cooling function with the separation function by using a single cooling step that simultaneously condenses waste gases (carbon dioxide and hydrogen sulfide) and facilitates their separation from the hydrocarbon gas stream. This integrated approach improves separation efficiency while managing energy consumption through process integration.
3Object-affected harmful factors
If waste gases are injected back into the formation, then ecological acceptability improves and hydrocarbon production is stimulated, but disposal cost and system complexity increase
Solution Approach 1:
The injection system serves multiple functions: it acts as a disposal mechanism for waste gases, a pressure maintenance system for the formation, and a production stimulation tool. By making the injection system multi-functional, the patent reduces the need for separate systems for each purpose, thereby managing complexity while achieving ecological and economic benefits.
Solution Approach 2:
The waste gases themselves serve the function of stimulating production when injected into the formation. The injected gases maintain formation pressure and displace hydrocarbons, making the waste product useful to the system that generates it, thus creating a self-service loop that reduces the need for external intervention.
4Manufacturing precision
If methanol is used for carbon dioxide absorption, then carbon dioxide removal efficiency improves, but operational cost increases due to methanol consumption
Solution Approach 1:
The patent recovers and recycles methanol after it has absorbed carbon dioxide. The methanol-carbon dioxide solution is processed to strip the carbon dioxide from the methanol, allowing the methanol to be reused for further carbon dioxide absorption. This recovery and recycling process eliminates continuous methanol consumption, reducing operational costs while maintaining high carbon dioxide removal efficiency.
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 prevents atmospheric venting of harmful gases, economically benefits by reusing methanol for carbon dioxide absorption, and stimulates hydrocarbon production by injecting waste gases back into the ground, promoting ecological acceptability and economic efficiency.
Implementation Method 1
a first means connected to receive the produced gas and operable to absorb carbon dioxide therefrom
Implementation Method 2
a second means connected to receive the produced gas and operable to cool the produced gas to a temperature below the dew point of the produced gas
Implementation Method 3
a third means connected to receive the produced gas and operable to separate the produced gas into a first stream containing hydrocarbon gas and a second stream containing waste gas
Data Source
AI summary
Produced natural gas containing carbon dioxide is dehydrated and chilled to liquefy the carbon dioxide and then fractionated to produce a waste stream of liquid carbon dioxide and hydrogen sulfide. Natural gas liquids may be first separated and removed before fractionation. After fractionation, the waste stream is pressurized and transmitted to a remote injection well for injection either for disposal of the waste stream and preferably to urge hydrocarbons toward the producing well. A hydrocarbon stream proceeds from fractionation to a methanol absorber system which removes carbon dioxide gas. The hydrocarbon stream is thereafter separated into at least hydrocarbon gas, nitrogen and helium. Some of the nitrogen is reintroduced into a fractionation tower to enhance the recovery of hydrocarbons. A methanol recovery system is provided to recover and reuse the methanol. The hydrocarbons are sold as natural gas and the helium is recovered and sold. Excess nitrogen is vented.