Personal hydrogen sulfide gas alarm system

Abstract

A person-carried hydrogen sulfide instrument is adapted for use with a conventional SCADA system or other type of fault monitoring system normally intended for monitoring well-related conditions at a well site. In response to detecting an abnormally high concentration of hydrogen sulfide gas, the instrument triggers the fault monitoring system to record an H2S fault and convey that information to a remote computer. In some embodiments, the instrument includes a signal relay unit that listens to a conventional H2S monitor. The signal relay unit has a learning mode that teaches the unit to recognize an audible alarm from the H2S monitor. In response to bearing the H2S alarm, the signal relay unit emits a trigger signal to the fault monitoring system.

1. A personal alarm system for responding to hydrogen sulfide gas at a well site that is at  a remote location relative to a host computer, comprising:
 a person-carried alarm instrument providing a trigger signal in response to a concentration of hydrogen sulfide gas reaching a predetermined limit;  
 a fault monitoring system set up at a generally fixed location at the well site  remote location, wherein the person-carried alarm instrument is movable relative to the fault monitoring system;  
 a first wireless communication link having a limited distance range between the person-carried alarm instrument and the fault monitoring system, wherein the first wireless communication link conveys the trigger signal from the person-carried alarm instrument to the fault monitoring system;  
 an alarm status signal created by the fault monitoring system in response to receiving the trigger signal from the person-carried alarm instrument; and  
 a second wireless communication link having a greater distance range between the fault monitoring system and the host computer, wherein the greater distance range is greater than the limited distance range, and wherein the second wireless communication link conveys the alarm status signal from the fault monitoring system to the host computer, whereby the host computer is notified that the concentration of hydrogen sulfide gas reached the predetermined limit at the well site  remote location.  
 
     
     
       2. The personal alarm system of  claim 1 , wherein the person-carried alarm instrument includes an H2S monitor and a signal relay unit, and further comprising an alarm signal generated by the II2S monitor in response to the II2S monitor detecting that the concentration of hydrogen sulfide gas has reached the predetermined limit, wherein the signal relay unit provides the trigger signal in response to detecting that the H2S monitor generated the alarm signal. 
     
     
       3. The personal alarm system of  claim 2 , wherein the signal relay unit includes a microphone and the alarm signal is audible, whereby the signal relay unit uses the microphone to detect that the H2S monitor generated the alarm signal. 
     
     
       4. The personal alarm system of  claim 3 , wherein the signal relay unit includes a learning mode, wherein the signal relay unit learns and distinguishes the alarm signal from other background sounds. 
     
     
       5. The personal alarm system of  claim 1 , further comprising an inquiry signal periodically conveyed from the host computer to the fault monitoring system, wherein the alarm status signal is inhibited from being conveyed to the host computer until the inquiry signal is conveyed to the fault monitoring system. 
     
     
       6. The personal alarm system of  claim 1 , wherein the fault monitoring system includes a memory that remembers that the person-carried alarm instrument provided the trigger signal even after the trigger signal is discontinued. 
     
     
       7. The personal alarm system of  claim 1 , wherein the fault monitoring system monitors a plurality of potential faults at the known well site  remote location, wherein the plurality of potential faults includes the concentration of hydrogen sulfide gas reaching the predetermined limit. 
     
     
       8. A personal alarm system for responding to hydrogen sulfide gas at a known well site that is at a remote location relative to a host computer, wherein a well-related operation may occur at the known well site, the personal alarm system comprising:
 a person-carried alarm instrument providing a trigger signal in response to a concentration of hydrogen sulfide gas reaching a predetermined limit;  
 a fault monitoring system set up at a generally fixed location at the known well site to monitor the well-related operation, wherein the person-carried alarm instrument is movable relative to the fault monitoring system;  
 a first wireless communication link having a limited distance range between the person-carried alarm instrument and the fault monitoring system, wherein the first wireless communication link conveys the trigger signal from the person-carried alarm instrument to the fault monitoring system;  
 a memory included with the fault monitoring system, wherein the fault monitoring system remembers receiving the trigger signal even after the trigger signal is discontinued;  
 an alarm status signal created by the fault monitoring system in response to receiving the trigger signal from the person-carried alarm instrument;  
 an inquiry signal periodically conveyed from the host computer to the fault monitoring system; and  
 a second wireless communication link having a greater distance range between the fault monitoring system and the host computer, wherein the greater distance range is greater than the limited distance range, and wherein the second wireless communication link conveys the alarm status signal from the fault monitoring system to the host computer in response to the fault monitoring system receiving the inquiry signal from the host computer, whereby the host computer is notified that the concentration of hydrogen sulfide gas reached the predetermined limit at the known well site.  
 
     
     
       9. The personal alarm system of  claim 8 , wherein the memory includes a latch relay. 
     
     
       10. The personal alarm system of  claim 8 , wherein the person-carried alarm instrument includes an H2S monitor and a signal relay unit, and further comprising an alarm signal generated by the H2S monitor in response to the H2S monitor detecting that the concentration of hydrogen sulfide gas has reached the predetermined limit, wherein the signal relay unit provides the trigger signal in response to detecting that the H2S monitor generated the alarm signal. 
     
     
       11. The personal alarm system of  claim 10 , wherein the signal relay unit includes a microphone and the alarm signal is audible, whereby the signal relay unit uses the microphone to detect that the H2S monitor generated the alarm signal. 
     
     
       12. The personal alarm system of  claim 10 , wherein the signal relay unit includes a learning mode, wherein the signal relay unit learns to recognize the alarm signal so the signal relay unit can later distinguish the alarm signal from other background sounds. 
     
     
       13. The personal alarm system of  claim 8 , wherein the well-related operation involves conveying a fluid. 
     
     
       14. A method for responding to hydrogen sulfide gas at a well site that is at a remote location relative to a host computer, the method comprising:
 placing a fault monitoring system at a generally fixed location at the well site;  
 performing a well-related operation at the well site;  
 generating a fault signal in response to an operational fault occurring with the well-related operation;  
 communicating the fault signal to the fault monitoring system;  
 providing a person-carried alarm instrument at the well site, wherein the person-carried alarm instrument provides a trigger signal in response to sensing a concentration of hydrogen sulfide gas has reached a predetermined limit;  
 carrying the person-carried alarm instrument at the well site, whereby the person-carried alarm instrument travels relative to the fault monitoring system;  
 communicating via a first wireless communication link the trigger signal from the person-carried alarm instrument to the fault monitoring system; and  
 communicating via a second wireless communication link a first alarm status signal and a second alarm status signal from the fault monitoring system to the host computer, wherein the first alarm status signal corresponds to the fault signal of the well-related operation and the second alarm status signal corresponds to the trigger signal of the person-carried alarm instrument.  
 
     
     
       15. The method  claim 14 , wherein the person-carried alarm instrument includes an H2S monitor and a signal relay unit, and further comprising generating an audible alarm via the H2S monitor, and conveying the audible alarm from the H25 monitor to the signal relay unit, wherein the signal relay unit provides the trigger signal in response to receiving the audible alarm signal from the H25 monitor. 
     
     
       16. The method of  claim 15 , further comprising teaching the signal relay unit to recognize the audible alarm generated by the H2S monitor. 
     
     
       17. The method of  claim 14 , further comprising pinging the fault monitoring system via the host computer, wherein the step of communicating the first alarm status signal and the second alarm status signal is performed in response to the step of pinging the fault monitoring system. 
     
     
       18. The method of  claim 14 , further comprising via the fault monitoring system remembering the occurrence of the fault signal even after the fault signal is discontinued. 
     
     
       19. The method of  claim 14 , further comprising via the fault monitoring system remembering the occurrence of the trigger signal even after the trigger signal is discontinued. 
     
     
       20. A method for responding to hydrogen sulfide gas at a well site that is at a remote location relative to a host computer, wherein a service vehicle facilitates performing a service operation at the well site, the method comprising:
 using the service vehicle to transport a fault monitoring system to the well site;  
 parking the service vehicle at the well site, thereby placing the fault monitoring system at a generally fixed location at the well site;  
 performing the service operation at the well site;  
 providing a person-carried alarm instrument at the well site, wherein the person-carried alarm instrument provides a trigger signal in response to sensing a concentration of hydrogen sulfide gas has reached a predetermined limit;  
 carrying the person-carried alarm instrument at the well site, whereby the person-carried alarm instrument travels relative to the fault monitoring system which is at the generally fixed location;  
 communicating via a first wireless communication link the trigger signal from the person-carried alarm instrument to the fault monitoring system;  
 communicating via a second wireless communication link an alarm status signal from the fault monitoring system to the host computer, wherein the alarm status signal corresponds to the trigger signal of the person-carried alarm instrument; and  
 communicating via the second wireless communication link a well location signal from the fault monitoring system to the host computer, wherein the well location signal identifies the remote location of the well site, whereby the host computer is notified that the concentration of hydrogen sulfide gas reached the predetermined limit at the remote location of the well site.