Abstract: The study of well log cyclostratigraphy is mainly based on the Milankovitch astronomical theory, using logging data as a proxy for astronomical cycles to investigate scientific issues in geology, environment, climate, and other fields. Currently, there is still a lack of specialized software for the processing and analysis of well log cyclostratigraphy both domestically and internationally. In this paper, a well log cyclostratigraphy analysis module is developed using Java language based on the CIFLog software, which includes necessary functions such as preprocessing, astronomical testing, filtering and tuning. The effectiveness of each function is verified using theoretical curves as test data. We select the Th content data from natural gamma ray spectroscopy  logging of  Qingshankou Formation in Well SK-2 in  Songliao basin for processing and successfully identify and extract 13 long eccentricity signals. The sedimentation rate is estimated to be 5.6 cm/ka, and a floating astronomical time scale has been  established.

Key words: well log, Milankovitch cycles, CIFLog, software development, Well SK-2