Downhole membrane system to control natural gas production
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.
1 . A method for controlling production of natural gas from a formation below a surface, the method comprising:
installing a membrane module, comprising a membrane, downhole, wherein the membrane selectively permeates NGL over methane;
separating high pressure natural gas feed with the membrane module into an NGL rich permeate and a methane rich retentate;
carrying the permeate through a first line from the membrane module to a gas plant located above the surface;
carrying the retentate from the membrane module through a second line for injection into a storage zone below the surface without introducing the retentate to the surface;
storing the retentate in the storage zone; and
recovering the retentate from the storage zone through a third line.
2 . The method of claim 1 , wherein contaminants are removed from the permeate in the gas plant to manufacture an NGL product stream.
3 . The method of claim 1 , wherein contaminants are removed from the recovered retentate in the gas plant.
4 . The method of claim 1 , further comprising recovering the retentate through from the storage zone through a third line to the gas plant; wherein contaminants are removed, producing a natural gas product.
5 . A system for controlling production of natural gas, comprising:
a membrane module installed downhole within a casing of a wellbore in a production reservoir, the membrane module configured for receiving a feed comprising a high-pressure natural gas from the production reservoir, and separating the high pressure natural gas into a permeate rich in NGL and a retentate rich in methane;
a gas plant located at a surface;
a first line within the casing for carrying the permeate from the membrane module to the gas plant;
a storage zone located below the surface;
a second line within the casing for carrying the retentate from the membrane module to the storage zone without introducing the retentate to the surface; and
a production line within the casing for recovering methane rich gas from the storage zone to the gas plant.
6 . The system of claim 5 , wherein the
membrane module incases a membrane made of a material selected from the group composed of Poly(dimethylsiloxane) (PDMS), Poly (1-trimethylsilyl-1-propyne) (PTMSP), poly(octyl-methyl-siloxane) (POMS) and combinations thereof.
7 . The system of claim 5 , wherein the membrane module is fabricated from stainless steel.
8 . The system of claim 5 , wherein the gas plant is configured for refining the permeate through the first line to produce an NGL product from the permeate.
9 . The system of claim 5 , comprising:
at least one seal installed between the membrane module and a casing for preventing a natural gas from bypassing the membrane module and maintaining high pressure in the feed.
10 . The system of claim 5 , wherein the
gas plant is configured for refining methane rich gas received through the production line to produce a natural gas product from the storage zone.
11 . The system of claim 10 , wherein the gas plant further comprises:
a system configured for removing contaminants from the permeate to manufacture NGL products.