A New Gas Logging Method Based on Semipermeable Film Degasser and Infrared Spectrum

The current gas logging electric degasser is susceptible to various factors, such as drilling fluid displacement, drilling fluid level height, motor speed, and drilling fluid properties. Consequently, the degassing efficiency varies, and quantification is poor. The gas chromatographic analysis time is lengthy, the gas path structure is complex, and the operation process is intricate. These factors distort gas measurement data and compromise the accuracy of hydrocarbon discovery and interpretation. To address these issues associated with traditional logging equipment, a novel gas logging instrument based on semipermeable film degasser and infrared spectroscopy has been developed. This instrument utilizes the principle of quantitative separation of gas and liquid through a semipermeable membrane combined with rapid and highly sensitive infrared spectroscopic analysis for precise gas characterization. Laboratory and field tests demonstrate excellent repeatability and stability of this instrument while meeting the detection range requirements for alkane gas concentration in oil fields. Comparison between the hydrocarbon curves obtained from both electric degasser and membrane degassing reveals similar trends; however, the latter provides more comprehensive information.