Natural Gas Processing for CO2 Liquefaction and Reinjection
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Solution Overview
Problem
Current processes fail to rapidly and ecologically acceptably dispose of unusable gases like carbon dioxide and hydrogen sulfide from produced gas, which are often vented into the atmosphere, posing environmental concerns and not enhancing hydrocarbon production.
Innovation Solution
A gas processing system that dehydrates and cools the produced gas 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 well, where they can be disposed of in a stratum to enhance hydrocarbon recovery.
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 quick, 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 substance by injecting them back into the underground formation to stimulate hydrocarbon production. The waste gases are no longer vented but instead serve as a means to enhance oil and gas recovery, transforming an environmental problem into an economic benefit.
Solution Approach 2:
The patent changes the physical state parameter of the waste gases from gaseous to liquid form through cooling and compression processes. This phase change enables the gases to be injected into the formation more effectively and allows for controlled disposal that enhances hydrocarbon production while avoiding atmospheric emissions.
2Reliability
If waste gases are separated and disposed of conventionally, then hydrocarbon separation is achieved, but disposal costs increase and ecological benefit is lost
Solution Approach 1:
Instead of treating waste gas disposal as a cost center, the patent transforms it into a revenue-generating activity. The separated waste gases are injected into the formation to stimulate production, creating additional hydrocarbon recovery that offsets the separation and processing costs, thereby converting a loss into a gain.
Solution Approach 2:
The waste gases themselves serve the dual purpose of being the substance to be disposed of and the medium to stimulate production. By injecting the separated waste gases back into the formation, the system uses the problematic material as a tool to enhance its own productivity, eliminating the need for separate disposal infrastructure and reducing overall costs.
3Productivity
If rapid removal of waste gases is implemented, then disposal efficiency improves, but process complexity increases
Solution Approach 1:
The patent merges the waste gas separation process with the hydrocarbon production enhancement process into a single integrated system. The separation units that remove waste gases are directly connected to injection systems that deliver the separated gases to the formation, eliminating the need for separate disposal infrastructure and reducing overall system complexity despite the rapid removal capability.
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 method prevents atmospheric venting of harmful gases, economically benefits by avoiding venting costs, and stimulates hydrocarbon production by injecting waste gases back into the formation to urge hydrocarbons towards producing wells.
Implementation Method 1
The produced gas is cooled in a heat exchanger to a temperature where at least some of the waste gas is in liquid form
Implementation Method 2
The cooled and dehydrated produced gas is processed in a processor to separate the cooled and dehydrated produced gas into a stream with hydrocarbons and a stream with waste gas
Implementation Method 3
The waste gas as liquid is delivered by the injection well to a formation for disposal and to stimulate production from producing wells in the area
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.