Method of capturing gasses from upstream well during plug drill-out operations, with the use of seperators, regulation control, flaring and cross-compression technique

Abstract

A method to capture gasses from an upstream underground well during a frac plug drill-out operations, with the use of multiple separation vessels, cross-compression units, flaring and regulation control. The method allows capturing gasses out of a fluid mixture, from the underground well, with flowing the fluid mixture from the underground well towards sequentially a mud-gas separation vessel and a separation vessel, whereby the fluid mixture contains a solid and liquid phase and a gas phase. The method also includes separating the fluid mixture into the solid and liquid phase and the gas phase. The method further includes simultaneously flowing the gas phase towards a flare for burning and towards a sales line, through one or more cross-compression units. One goal of the method may be to recover most of the gas phase towards the sales line for valuing it instead of discharging it to the atmosphere.

What is claimed is: 
     
         1 . A method to capture gasses out of a fluid mixture, from an underground well, during a frac plug drill-out operation comprising:
 flowing the fluid mixture from the underground well towards sequentially a mud-gas separation vessel and a separation vessel,
 whereby the fluid mixture contains a solid and liquid phase and a gas phase; 
   separating the fluid mixture in the solid and liquid phase and the gas phase, inside sequentially the mud-gas separation vessel and the separation vessel;   simultaneously flowing the gas phase towards a flare for burning and towards a sales line, through one or more cross-compression units.   
     
     
         2 . The method of  claim 1 , whereby flowing the gas phase towards the flare for burning, includes passing through a flow control valve. 
     
     
         3 . The method of  claim 1 , whereby the mud-gas separation vessel and the separation vessel are positioned in series, whereby one output of the separation of the fluid mixture inside the mud-gas separation vessel is an intermediary gas phase, whereby the intermediary gas phase is the input of the separation vessel. 
     
     
         4 . The method of  claim 3 , whereby the intermediary gas phase is separated into a liquid phase and into the gas phase, inside the separation vessel. 
     
     
         5 . The method of  claim 4 , whereby the liquid phase is pulled out of the separation vessel towards either a vacuum truck or back to the mud-gas separation vessel through a fluid pump. 
     
     
         6 . The method of  claim 2 , whereby adjusting the volumetric flow rate of the gas phase towards the flare versus adjusting the volumetric flow rate of the gas phase towards the sales line is achieved by both adjusting the flow control valve and adjusting the rate of the one or more cross-compression units. 
     
     
         7 . The method of  claim 1 , whereby the sales line is used to recover and value the gas phase for future use. 
     
     
         8 . The method of  claim 7 , whereby adjusting the volumetric flow rate of the gas phase towards the flare versus adjusting the volumetric flow rate of the gas phase towards the sales line, is achieved through a regulation method. 
     
     
         9 . The method of  claim 8 , whereby the regulation method is manual or automated,
 whereby the regulation method is updated at a frequency between 1 sec and 10 hours.   
     
     
         10 . The method of  claim 8 , whereby the regulation method achieves maintaining the ratio of the volumetric flow rate of the gas phase towards the sales line versus the volumetric flow rate of the gas phase towards the flare, at a wished ratio level,
 wherein a ratio level of 1 means 100% of the volumetric flow rate of the gas phase towards the sales line and 0% of the volumetric flow rate of the gas phase towards the flare,   wherein the wished ratio level of volumetric flow rate of the gas phase towards the sales line, versus the volumetric flow rate of the gas phase towards the flare, is between 0.6 and 1.   
     
     
         11 . The method of  claim 10 ,
 wherein the volumetric flow rate of the gas phase towards the flare is considered as an excess product.   
     
     
         12 . The method of  claim 10 ,
 whereby the wished level of volumetric flow rate of the gas phase towards the sales line, versus the volumetric flow rate of the gas phase towards the flare, depends on the discharge rate of the one or more cross-compression units.   
     
     
         13 . The method of  claim 5 , whereby the separation vessel includes a level indicator or a level controller, wherein the level indicator or the level controller allows determining the position of the liquid phase versus the gas phase inside the separation vessel. 
     
     
         14 . The method of  claim 13 , whereby the level indicator or the level controller provides a feedback signal to operate the fluid pump for the back pull of the fluid phase towards the mud-gas separation vessel or to operate the vacuum truck. 
     
     
         15 . The method of  claim 1 , whereby the mud-gas separation vessel and the separation vessel are located on surface, at proximity of a well head of the underground well.