Abstract: A great number of new technology, such as PDC bit and extended reach well are widely adopted in the Bohai Oilfield. It makes the cuttings too fine to be identified by conventional methods. medium-deep stratigraphic interfaces are also hard to be accurately recognized. The situation does not satisfy the requirements of lithologic identification and the establishment of lithological sections during drilling. To resolve these issues, the X-ray diffraction (XRD) logging technology for whole-rock is imported into the Bohai oilfield for identification of quantitative mineral composition. Lithology is easy to be identified according to the change in characteristic minerals.In addition, the change in mineral contents of the sediments formed in different depositional environments provides a useful tool for stratigraphic classification. The technology is a strong support to fast identification of lithology and stratigraphic interface in-situ.