Downhole Membrane Separation for Subsurface Methane Storage
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Solution Overview
Problem
The high cost and inefficiency of storing excess natural gas on the surface due to fluctuating demand, which requires additional infrastructure that may not be economically feasible.
Innovation Solution
A downhole membrane system installed within a wellbore that selectively separates NGL from methane, allowing NGL to be processed at the surface while storing methane-rich retentate in a subsurface storage zone for later recovery when demand increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If natural gas is stored on the surface, then excess natural gas can be stored, but it is costly and not economically feasible
Solution Approach 1:
The patent transitions natural gas storage from the surface dimension to the subsurface dimension by injecting methane-rich retentate into underground formations through injection wells. This dimensional change eliminates the need for costly surface storage facilities while providing large-capacity subsurface reservoirs for economic natural gas storage.
Solution Approach 2:
The patent extracts the NGL components from natural gas through membrane separation downhole, leaving behind methane-rich retentate that can be stored subsurface. This extraction of valuable NGL components enables the remaining methane to be stored economically underground rather than requiring surface storage for the entire natural gas mixture.
2Productivity
If a membrane system is installed downhole, then NGL can be separated and stored underground, but additional downhole equipment is required
Solution Approach 1:
The patent combines the membrane separation system with existing downhole well infrastructure by installing the membrane module within the wellbore. This merging of separation equipment with production wells eliminates the need for separate surface separation facilities and integrates multiple functions (production, separation, and storage) into a unified downhole system.
Solution Approach 2:
The downhole membrane system performs separation autonomously at the source of natural gas production, separating NGL from methane directly in the wellbore. This self-service approach at the production site eliminates the need for complex surface processing facilities and reduces the overall system complexity by handling separation downhole where the gas originates.
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
Enables continuous NGL production and storage of natural gas underground, reducing the need for surface facilities and allowing for efficient recovery when demand rises, thus optimizing resource utilization and reducing costs.
Implementation Method 1
a membrane selectively permeates natural gas liquids (NGL) over methane
Data Source
AI summary
A method for controlling production of natural gas includes a membrane module comprising a membrane that permeates NGL over methane, separating natural gas into an NGL rich permeate and a methane rich retentate, carrying the permeate from the membrane module to a gas plant, carrying the retentate from the membrane module for injection into a storage zone where the retentate is stored when demand is low; and recovered when demand is high. A system includes a membrane module for receiving a feed comprising natural gas, separating the natural gas into a permeate rich NGL and a retentate rich methane, a gas plant, a line for carrying the permeate from the membrane module to the gas plant, a storage zone; another line for carrying the retentate from the membrane module to the storage zone; and a production line for recovering methane rich gas from the storage zone to the gas plant.