Mobile gas separation unit

Abstract

The mobile gas separation unit is transportable from well site to well site. The mobile gas separation unit will separate CO 2 from natural gas at the well site where the natural gas is produced. The CO 2 may be a part of a fracturing fluid that is used to fracture the formation from which natural gas is to be produced. The CO 2 will be produced up the Well with the natural gas rather than venting or flaring the gas stream that includes the CO 2 in the atmosphere. The mobile gas separation unit will separate CO 2 from the gas stream so that a sales gas stream can be communicated to a natural gas sales pipeline or gathering system.

1 . A method of producing natural gas from a subterranean formation intersected by a wellbore extending from a well surface at a well site comprising: 
 fracturing the formation with a treating fluid that includes at least CO 2 ;    flowing a production stream to the surface, the production stream comprising CO 2  along with hydrocarbon fluids including at least natural gas to the well surface;    transporting a mobile separation unit to the well site; and    separating CO 2  from the production stream at the well site with the mobile separation unit.    
   
   
       2 . The method of  claim 1 , further comprising removing liquids from the production stream to form a production gas stream prior to the separating step.  
   
   
       3 . The method of  claim 2 , wherein the separating step comprises separating the production gas stream into a first gas stream and a second gas stream with the mobile separation unit, wherein the concentration of CO 2  in the first gas stream is lower than the concentration of CO 2  in the production gas stream, and the concentration of CO 2  in the second gas stream is higher than the concentration of CO 2  in the production gas stream.  
   
   
       4 . The method of  claim 2 , further comprising delivering a gas stream from the mobile separation unit to a natural gas sales pipeline after the separating step.  
   
   
       5 . The method of  claim 2 , wherein the separating step comprises separating the production gas stream into first and second gas streams, the first gas stream comprising less than 3 percent CO 2 .  
   
   
       6 . The method of  claim 1 , further comprising moving the mobile separation unit from the well site to a second well site to separate CO 2  from a stream flowing from a wellbore at the second well site.  
   
   
       7 . The method of  claim 6 , wherein the moving step occurs after the CO 2  concentration in the production gas stream is at or below a level specified by a purchaser of the natural gas.  
   
   
       8 . The method of  claim 6 , wherein the moving step occurs after the CO 2  concentration in the production gas stream is less than about 3 percent.  
   
   
       9 . A method of removing CO 2  from a production stream comprising at least CO 2  and natural gas produced from a formation intersected by a wellbore extending from a well surface at a well site comprising: 
 transporting a mobile separation unit to the well site;    removing liquids from the production stream to form a production gas stream;    communicating the production gas stream to the mobile separation unit; and    removing CO 2  from the production gas stream to form a sales gas stream having a CO 2  concentration less than the CO 2  concentration in the production gas stream.    
   
   
       10 . The method of  claim 9 , wherein the concentration of CO 2  in the sales gas stream is less than about five percent.  
   
   
       11 . The method of  claim 9 , wherein the concentration of CO 2  in the sales gas stream is less than about three percent.  
   
   
       12 . The method of  claim 9 , further comprising delivering the sales gas stream to a natural gas sales pipeline.  
   
   
       13 . The method of  claim 9 , wherein the CO 2  comprises CO 2  used to treat the formation.  
   
   
       14 . The method of  claim 13 , wherein the treatment comprises fracturing the formation.  
   
   
       15 . The method of  claim 9 , further comprising mounting the mobile separation unit to a trailer and moving the mobile separation unit to a second well site.  
   
   
       16 . A method for optimizing production from a wellbore extending between a downhole producing formation and an associated well surface comprising: 
 treating the downhole producing formation with a treating fluid that includes CO 2  to improve production of hydrocarbon fluids including natural gas from the downhole producing formation;    flowing a stream of the treating fluid and hydrocarbon fluids including natural gas from the downhole producing formation through the wellbore to the well surface;    separating liquids from the stream of treating fluid and hydrocarbon fluids at the well surface to form a production gas stream including at least CO 2  gas and natural gas; and    separating the production gas stream at the well surface into first and second gas streams, the first gas stream having a higher natural gas to CO 2  ratio than the production gas stream and the second stream having a lower natural gas to CO 2  ratio than the production stream.    
   
   
       17 . The method of  claim 16 , wherein the concentration of CO 2  gas in the first gas stream is less than three percent.  
   
   
       18 . The method of  claim 16 , further comprising directing the first gas stream to a natural gas gathering system.  
   
   
       19 . The method of  claim 16 , further comprising directing the first gas stream to a natural gas sales pipeline.  
   
   
       20 . The method of  claim 16 , further comprising using a mobile gas separator at the associated well surface to separate the production gas stream into the first gas stream and the second gas stream.  
   
   
       21 . A method for optimizing production of natural gas at a well site from a downhole producing hydrocarbon formation comprising: 
 injecting treating fluids including CO 2  through at least one wellbore into the hydrocarbon producing formation to increase fluid flow from the hydrocarbon producing formation;    flowing fluid including CO 2  and natural gas from the hydrocarbon formation through the at least one wellbore to an associated well surface at the well site;    separating liquid from the fluid at the well surface;    directing all gases from the fluid, including natural gas and CO 2 , to a gas separation unit;    removing CO 2  gas from the gases; and    directing natural gas to a natural gas sales pipeline.    
   
   
       22 . The method of  claim 21 , further comprising transporting the gas separation unit to the well site to perform the removing step.  
   
   
       23 . The method of  claim 21 , further comprising moving the gas separation unit to the well site on a trailer.  
   
   
       24 . The method of  claim 21 , the removing step comprising removing CO 2  gas to form a sales gas stream comprising at least natural gas and CO 2 , the CO 2  comprising less than 3 percent of the sales gas stream.  
   
   
       25 . The method of  claim 21 , further comprising: 
 continuing the removing step until the concentration of CO 2  in the gases in the fluid flowing from the at least one wellbore is within a range specified by a buyer of the natural gas; and    moving the gas separation unit from the well site to a second well site, or to a holding location for storage until the gas separation unit is to be moved to and used at a second well site.