Abstract: The lithology of metamorphic buried hill is complex and diverse, and the reservoir is highly non-homogenous. The conventional mud-logging method can only qualitatively judge the development location of the submarine reservoir based on oil and gas shows, and it is difficult to accurately identify the physical properties of the submarine reservoir. To address this problem, the light-colored mineral mud-logging characterization technology of metamorphic buried hills, the bedrock mechanics mud-logging characterization technology of metamorphic buried hills, and the drillability evaluation technology of metamorphic buried hills were innovatively established through starting from comprehensive geological experiments and microdrilling simulation experiments and applying the XRF elemental logging, the XRD whole-rock diffraction mud-logging and engineering mud-logging data to form comprehensive evaluation techniques and quantitative evaluation standards for mud-logging on the effectiveness of metamorphic buried hill reservoirs based on various perspectives such as rock mineralogy, rock mechanics and rock fragmentation. The research results have been applied to more than 50 wells in the metamorphic buried hills of the Bozhong Depression in the Bohai Sea area, and the average compliance rate of the reservoir effectiveness mud-logging interpretation is as high as 81.7% when compared with the conclusion of the logging interpretation. This technology plays an important role in the discovery and evaluation of reservoirs in the metamorphic buried hills of the Bozhong Depression in the Bohai Sea area, and provides a reliable basis for major exploration decisions such as midway testing and completion drilling, and has a good application prospect.

Key words: metamorphic buried hill, reservoir effectiveness, light-colored mineral, bedrock mechanics, mechanical specific energy, mud-logging comprehensive evaluation, Bozhong Depression