MULTISTAGE SEPARATOR VESSEL FOR CAPTURING LPGs

Abstract

A method of recovering liquid petroleum gases (LPGs) from a wellbore includes: performing a well treatment operation by injecting the LPGs into the wellbore to increase the wellbore pressure; flowing a fluid stream from the wellhead into a separation vessel, the fluid stream comprising the LPGs; reducing the pressure of the fluid stream from the wellbore pressure to a separation vessel pressure, the fluid stream in the separation vessel comprising the LPGs in liquid form and in vapour form; separating the vapour form from the liquid form; transferring the liquid form of the LPGs to a pressure vessel; and passing the vapour form through a condenser to condense the vapour form, and depositing the condensed vapour form into the pressure vessel.

1 . A method of recovering liquid petroleum gases (LPGs) from a wellbore, the wellbore having a wellbore pressure, the method comprising the steps of:
 performing a well treatment operation by injecting the LPGs into the wellbore to increase the wellbore pressure;   flowing a fluid stream from the wellhead into a separation vessel, the fluid stream comprising the LPGs;   reducing the pressure of the fluid stream from the wellbore pressure to a separation vessel pressure, the fluid stream in the separation vessel comprising the LPGs in liquid form and in vapour form;   separating the vapour form from the liquid form;   transferring the liquid form of the LPGs to a pressure vessel;   passing the vapour form through a condenser to condense the vapour form, and depositing the condensed vapour form into the pressure vessel.   
     
     
         2 . The method of  claim 1 , wherein the liquid petroleum gases comprise at least 80% propane by weight. 
     
     
         3 . The method of  claim 1 , wherein the liquid petroleum gases comprise at least 90% propane by weight. 
     
     
         4 . The method of  claim 1 , wherein the liquid petroleum gases comprise at least 80% butane by weight. 
     
     
         5 . The method of  claim 1 , wherein the separation vessel pressure is less than 500 psi. 
     
     
         6 . The method of  claim 1 , wherein the separation vessel pressure is less than 200 psi. 
     
     
         7 . The method of  claim 1 , wherein the separation vessel pressure is less than 100 psi. 
     
     
         8 . The method of  claim 1 , wherein the separation vessel pressure is less than 75 psi. 
     
     
         9 . The method of  claim 1 , wherein the well treatment operation is a fracturing operation. 
     
     
         10 . The method of  claim 1 , wherein passing the vapour form through a condenser comprises filtering the condensed liquid petroleum gases to remove entrained water and solid particles prior to condensing the vapour form. 
     
     
         11 . The method of  claim 1 , further comprising the step of analyzing the composition of the fluid stream, and activating a heater to heat the fluid stream between the wellbore and the separation vessel in order to vapourize the LPGs once the LPG component of the fluid stream drops below a predetermined threshold. 
     
     
         12 . The method of  claim 11 , wherein analysing the composition of the fluid stream comprises analysing the vapour phase, the liquid phase, or both exiting the separation vessel. 
     
     
         13 . The method of  claim 11 , further comprising the step of, once the heater is activated, transferring hydrocarbon liquids from the separation vessel to a production fluid facility.