In-borehole gas monitor apparatus and method comprising a voc concentration analyser and a voc collector

Abstract

In-Borehole Gas Monitor Apparatus and Method An in-borehole gas monitor (IGM) apparatus comprising a VOC concentration analyser and a VOC collector.

1 . An in-borehole gas monitor (IGM) apparatus comprising a VOC concentration analyser and a VOC collector. 
     
     
         2 . The in-borehole gas monitor (IGM) apparatus of  claim 1 , wherein the VOC concentration analyser is configured to provide a non-specific real-time concentration of VOCs. 
     
     
         3 . The in-borehole gas monitor (IGM) apparatus of  claim 1 , wherein the VOC concentration analyser comprises a photo-ionisation detector. 
     
     
         4 . The in-borehole gas monitor (IGM) apparatus of  claim 1 , wherein the VOC collector is configured to provide a specific concentration by volume. 
     
     
         5 . The in-borehole gas monitor (IGM) apparatus of  claim 1 , wherein the VOC collector comprises a sorbent material. 
     
     
         6 . The in-borehole gas monitor (IGM) apparatus of  claim 1 , wherein the apparatus further comprises a pressure sensor configured to measure atmospheric pressure. 
     
     
         7 . The in-borehole gas monitor (IGM) apparatus of  claim 1 , wherein the apparatus further comprises a clock. 
     
     
         8 . The in-borehole gas monitor (IGM) apparatus of  claim 1 , wherein the apparatus comprises a pump for pumping gas past the VOC concentration analyser and the VOC collector in a downstream direction and the apparatus is configured whereby the VOC concentration analyser determines a VOC concentration at a predetermined time by the pump pumping borehole gas past the VOC concentration analyser and the VOC collector for a pumping period. 
     
     
         9 . The in-borehole gas monitor (IGM) apparatus of  claim 8  wherein, the apparatus is configured whereby the pumping period, a time of measurement and an atmospheric pressure at the time of measurement are recorded. 
     
     
         10 . The in-borehole gas monitor (IGM) apparatus of  claim 1 , wherein the apparatus comprises a pump for pumping gas past the VOC concentration analyser and the VOC collector in a downstream direction and a filter for removing any of particulates or moisture from a gas input, wherein the VOC concentration analyser and the VOC collector are upstream of the filter. 
     
     
         11 . The in-borehole gas monitor (IGM) apparatus of  claim 1 , wherein the apparatus comprises a pump for pumping gas past the VOC concentration analyser and the VOC collector in a downstream direction and there is a gas flow path comprising a gas input, a first valve upstream of the pump and a pressure sensor, wherein the apparatus is configured whereby with the first valve closed the pump is activated for a predetermined period and if within the predetermined period a predetermined pressure is not exceeded, as measured by the pressure sensor, a pump fail signal is generated. 
     
     
         12 . The in-borehole gas monitor (IGM) apparatus of  claim 11 , wherein the predetermined period is between 8 and 12 seconds and the predetermined pressure is 100 mb. 
     
     
         13 . The in-borehole gas monitor (IGM) apparatus of  claim 1 , wherein the apparatus comprises a pump for pumping gas past the VOC concentration analyser and the VOC collector in a downstream direction and there is a gas flow path comprising a gas input, a first valve upstream of the pump, a pressure sensor and a filter, wherein the apparatus is configured whereby with the first valve open a first pressure sensor reading is taken, the pump is activated for a predetermined period after which a second pressure sensor reading is taken, and if the magnitude of the difference between the first pressure sensor reading and the second pressure sensor reading is greater than a predetermined value, a filter fail signal is generated. 
     
     
         14 . The in-borehole gas monitor (IGM) apparatus of  claim 13 , wherein the predetermined period is between 2 seconds and 6 seconds. 
     
     
         15 . The in-borehole gas monitor (IGM) apparatus of  claim 13 , wherein the predetermined value is 250 mb. 
     
     
         16 . The in-borehole gas monitor (IGM) apparatus of  claim 8 , wherein the time of sensing and the length of time for which the pump operates are recorded. 
     
     
         17 . The in-borehole gas monitor (IGM) apparatus of  claim 11  wherein, the apparatus comprises a second valve downstream of the first valve and a gas outlet. 
     
     
         18 . The in-borehole gas monitor (IGM) apparatus of  claim 1 , wherein the apparatus is configured to have a borehole side and an atmospheric side, wherein there is a gas outlet to the borehole side of the device and to the atmospheric side of the device. 
     
     
         19 . The in-borehole gas monitor (IGM) apparatus of  claim 1 , wherein the VOC concentration analyser and the VOC collector are in series in a gas flow path with a gas analyser. 
     
     
         20 . The in-borehole gas monitor (IGM) apparatus of  claim 19 , wherein the gas analyser analyses one or more of hydrocarbons, carbon dioxide, oxygen and hydrogen sulphide. 
     
     
         21 . A method of operation of an in-borehole gas monitor apparatus, which method comprises the use of an in-borehole gas monitor apparatus according to  claim 1 . 
     
     
         22 . The method of operation of an in-borehole gas monitor apparatus of  claim 21 , wherein the VOCs collected by the VOC collector are quantified. 
     
     
         23 . The method of operation of an in-borehole gas monitor apparatus of  claim 21 , wherein the apparatus comprises a pump for pumping gas from the borehole past the VOC collector and the VOC analyser, wherein the time of sensing and the length of time for which the pump operates are recorded to determine the volume of gas passing through the apparatus. This enables the VOC concentration to be determined.