A new infrared sensor for mud logging and formation evaluation

Summary form only given. Fast recognition of methane influx into the well and hydrocarbon composition evaluation in the circulated drilling fluid (mud) is of extreme importance for drilling safety and efficiency. FT-IR spectroscopy is now considered to be the best for oil "fingerprinting" in the laboratory environment. Recent progress in industrial applications of attenuated total reflectance (ATR) sampling technique for the online chemical process control together with the development of a fast computer controlled all-solid-state with no-moving-parts spectrograph based on the acousto-optic tunable filter (AOTF) principle allows the design of an IR chemical sensor capable of working in the hostile downhole environment. In this paper we address the problem of choosing an appropriate spectral region and report our experimental results on high pressure and elevated temperature testing of this new sampling technique.