Abstract: Although the application of stable carbon isotope geochemical analysis in oil and gas exploration and development sites has been gradually emphasized at home and abroad in recent years, domestic gas isotope logging tools cannot provide other alkane isotope data other than methane isotope data during logging. In this way, the shale gas “dessert” prediction and related geological analysis cannot be performed based on the “reverse order” characteristics of the carbon stable isotope. In order to promote the development of domestic gas isotope logging instruments, the structure, principle and performance characteristics of the Isologger gas isotope logging tool developed by CSS (Compact Science Systems) in the UK and capable of online analysis of C1-C5 isotope data are introduced. It consists of a stable isotope ratio mass spectrometer (IRMS), a gas chromatograph and a burner combination unit. The “reverse order” feature method for the isotope composition of shale gas “dessert” predicted by the carbon stable isotope data provided by the isotope logging instrument and the genesis of natural gas, shale gas and natural gas hydrate are analyzed. The analysis of the Bernard plate method; the sampling method of gas isotope logging, the number of parameter detection, software interpretation and instrument stability should be the focus of domestic research and development.
Key words: IRMS; shale gas; drilling fluid; gas isotope logging; data acquisition;