Detection of Alkane Gases in Oil and Gas Exploration by Dual Optical Path Infrared Absorption Spectroscopy

ABSTRACT With the expansion of global oil and gas industry, the exploration and development of clean energy sources such as shale gas and coal bed methane (CBM) have become increasingly important. Accurate and real‐time detection of hydrocarbon gases is crucial during oil and gas exploration and logging operations. This paper presents a novel near‐infrared differential absorption spectroscopy (NIR‐DOAS) for alkane gas detection in the field of oil and gas exploration. A dual optical path modulation technique is proposed to achieve full‐scale gas detection. The differential absorbance of alkane gases is obtained using the Savitzky–Golay digital filter method, and the concentrations are determined by the least squares algorithm. The experimental results demonstrate that the detection range spans from 10 × 10 −6 to 100% for methane (CH 4 ), 10 × 10 −6 to 10% for ethane (C 2 H 6 ) and propane (C 3 H 8 ), and 10 × 10 −6 to 1% for n ‐butane (n‐C 4 H 10 ) and isobutane(i‐C 4 H 10 ), respectively, with a detection accuracy of ± 2%. Furthermore, the developed system is capable of detecting mixtures of these alkane gases, making it suitable for online alkane gas detection in oil and gas exploration, development, and geological logging.