Patent ID: 7537641

Claim:
A process for treating a natural gas stream produced by a well that has been recently stimulated using a fracturing gas, and that contains an undesirable amount of the fracturing gas, comprising: (a) providing a membrane unit comprising: (i) a membrane having a feed side and a permeate side; (ii) automatic monitoring means positioned in a gas flow line to the membrane unit to monitor at least a concentration of the fracturing gas in the natural gas, a flow rate of the natural gas or a pressure of the natural gas; (iii) automatic control means connected in signal-transferring relationship to the automatic monitoring means and adapted to adjust at least one operating parameter of the membrane unit; (b) passing the natural gas stream through the gas flow line and across the feed side as a feed stream; (c) providing a driving force for transmembrane permeation; (d) withdrawing from the membrane unit a first treated gas stream enriched in the fracturing gas compared with the feed stream; (e) withdrawing from the membrane unit a second treated gas stream depleted in the fracturing gas compared with the feed stream; (f) adjusting the operating parameter in response to a change in at least one of the concentration, the flow rate and the pressure.