In-borehole gas monitor apparatus for monitoring concentration of e.g. gas, has volatile organic compound concentration analyzer providing non-specific real-time concentration of volatile organic compounds

NOVELTY - The apparatus (8) has a volatile organic compound (VOC) concentration analyzer to provide a non-specific real-time concentration of VOCs, where the VOC concentration analyzer includes a photo-ionization detector. A VOC collector (42) provides a specific concentration by volume, where the VOC collector comprises a sorbent material. A pressure sensor (46) measures atmospheric pressure, and a pump (48) pumps gas past the VOC concentration analyzer and the VOC collector in a downstream direction. USE - In-borehole gas monitor (IGM) apparatus for monitoring concentration of gas. Uses include but are not limited to methane, carbon dioxide, oxygen, carbon monoxide, and hydrogen sulphide. ADVANTAGE - The apparatus can be conveniently deployed in a borehole to take periodic data readings of gas variables in the borehole. The combination of the VOC concentration analyzer together with the VOC collector and the determination of the volume of gas passing through the apparatus enable a calculation to be made of the absolute concentrations of specific VOCs in the borehole and the variations of concentrations over time. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for operating an in-borehole gas monitor apparatus. DESCRIPTION Of DRAWING(S) - The drawing shows a schematic cross-sectional elevation of the in-borehole gas monitor apparatus.In-borehole gas monitor apparatus (8)Cap (10)Inner bore (12)Seal (16)Body portion (17)Volatile organic compound detector (40)Volatile organic compound collector (42)Filter (44)Pressure sensor (46)Pump (48)