System And Method For Detecting Hydrogen Sulfide In A Formation Sampling Tool

Abstract

A drilling system includes a downhole sampling tool configured to be placed in a wellbore of a subterranean formation and configured to pump formation fluid from the subterranean formation into the downhole sampling tool. The downhole sampling tool includes internal components configured to route the formation fluid through the downhole sampling tool and drill collars configured to hold the internal components of the downhole sampling tool. The downhole sampling tool also includes at least one coupon made from a material that is optically reactive to hydrogen sulfide (H2S). The coupon is disposed in a location that is exposed to the formation fluid that is pumped into the downhole sampling tool, and the location of the coupon is accessible from outside the downhole sampling tool without removing the internal components from the drill collars.

What is claimed is: 
     
         1 . A drilling system, comprising:
 a downhole sampling tool configured to be disposed in a wellbore of a subterranean formation and configured to pump formation fluid from the subterranean formation into the downhole sampling tool, wherein the downhole sampling tool comprises:
 internal components configured to route the formation fluid through the downhole sampling tool; 
 one or more drill collars configured to hold the internal components of the downhole sampling tool; and 
 at least one coupon comprising a material that is optically reactive to hydrogen sulfide (H2S), wherein the at least one coupon is disposed in a location that is exposed to the formation fluid that is pumped into the downhole sampling tool, wherein the location of the at least one coupon is accessible from outside the downhole sampling tool without removing the internal components from the one or more drill collars. 
   
     
     
         2 . The drilling system of  claim 1 , wherein the downhole sampling tool comprises a probe configured to function as an inlet for the formation fluid pumped into the downhole sampling tool, and wherein the probe comprises the location of the at least one coupon. 
     
     
         3 . The drilling system of  claim 1 , wherein the location of the at least one coupon comprises a flowline exit of the downhole sampling tool, wherein the flowline exit is disposed adjacent a drill collar and comprises a valve configured to release the formation fluid pumped through the downhole sampling tool. 
     
     
         4 . The drilling system of  claim 1 , wherein the downhole sampling tool comprises a hydraulic extender configured to couple two drill collars, wherein the hydraulic extender comprises the location of the at least one coupon. 
     
     
         5 . The drilling system of  claim 1 , wherein the downhole sampling tool further comprises a hydraulics module battery cap disposed between two drill collars, wherein the hydraulics module battery cap comprises the location of the at least one coupon. 
     
     
         6 . The drilling system of  claim 1 , wherein the downhole sampling tool further comprises a sample bottle, wherein the sample bottle is removable from the one or more drill collars and the internal components, and wherein the location of the at least one coupon comprises an inlet to the sample bottle. 
     
     
         7 . The drilling system of  claim 1 , comprising a first coupon comprising a first material that is optically reactive to H2S, and a second coupon comprising a second material that is optically reactive to H2S, wherein the first and second materials are sensitive to different levels of H2S. 
     
     
         8 . The drilling system of  claim 1 , wherein the at least one coupon is configured to be removable and replaceable by another at least one coupon. 
     
     
         9 . A drilling system, comprising:
 a downhole sampling tool configured to be disposed in a wellbore of a subterranean formation and configured to pump formation fluid from the subterranean formation into the downhole sampling tool, wherein the downhole sampling tool comprises:
 at least one coupon comprising a material that is optically reactive to hydrogen sulfide (H2S), wherein the at least one coupon is disposed in a location of the downhole sampling tool that is exposed to the formation fluid that is pumped into the downhole sampling tool; 
 wherein the at least one coupon, when in the location of the downhole sampling tool, is accessible from outside of the downhole sampling tool when the downhole sampling tool is fully assembled. 
   
     
     
         10 . The drilling system of  claim 9 , wherein the downhole sampling tool comprises a probe configured to function as an inlet for the formation fluid pumped into the downhole sampling tool, and wherein the location of the downhole sampling tool comprises a removable portion of the probe. 
     
     
         11 . The drilling system of  claim 10 , wherein the probe comprises a packer. 
     
     
         12 . The drilling system of  claim 10 , wherein the probe comprises a filter piston disposed in a probe module of the downhole sampling tool, and wherein the at least one coupon is mounted on a holder coupled with the filter piston. 
     
     
         13 . The drilling system of  claim 9 , wherein the at least one coupon is mounted in the downhole sampling tool via a holder, and wherein the at least one coupon is coupled to the holder and retained in place via pins or screws. 
     
     
         14 . The drilling system of  claim 9 , wherein the at least one coupon is mounted in the downhole sampling tool via a holder, and wherein the at least one coupon is brazed in place against the holder. 
     
     
         15 . The drilling system of  claim 9 , wherein the at least one coupon is mounted in the downhole sampling tool via a holder, and wherein the at least one coupon is press fit into the holder. 
     
     
         16 . The drilling system of  claim 9 , wherein the at least one coupon is mounted in the downhole sampling tool via a holder, and wherein the at least one coupon is spring-loaded for insertion into the holder. 
     
     
         17 . A method, comprising:
 at a rig site, disposing a downhole sampling tool into a well formed in a subterranean formation;   pumping formation fluid from the subterranean formation into a flowline of the downhole sampling tool;   exposing at least one coupon comprising a material that is optically reactive to hydrogen sulfide (H2S) to the formation fluid being pumped into the flowline of the downhole sampling tool;   raising the downhole sampling tool out of the well; and   accessing the at least one coupon at the rig site.   
     
     
         18 . The method of  claim 17 , comprising removing the at least one coupon from the downhole sampling tool at the rig site. 
     
     
         19 . The method of  claim 17 , wherein accessing the at least one coupon at the rig site comprises disassembling a series of drill collars holding internal components to expose the at least one coupon without removing the internal components from the one or more drill collars. 
     
     
         20 . The method of  claim 17 , wherein accessing the at least one coupon at the rig site comprises accessing the at least one coupon at a location within a probe of the downhole sampling tool when the downhole sampling tool is fully assembled.