关键词: 变质岩潜山, 裂缝性储层, 风化壳储层, 源-储配置, 新生古储, 太古界, 滨县凸起, 东营凹陷, 渤海湾盆地

Abstract:

By comprehensively utilizing technologies such as core observation, physical property testing, conventional logging, and imaging logging, reservoir formation conditions and hydrocarbon accumulation models of the buried hill in Binxian uplift of Dongying Sag in Bohai Bay Basin were systematically analyzed. Research results show that: （1） Archean reservoir types of Binxian uplift in Dongying Sag are fractured reservoirs and weathered crust reservoirs,with the weathered crust exhibiting a double-layer structure of dissolution layer and disintegration layer. Dissolution layers are mostly distributed in the lower part of the slope, making them optimal reservoirs. （2） The buried hill oil source of the study area comes from the third member of Shahejie Formation（Es3） and the fourth member of Shahejie Formation （Es4） source rocks in Lijin sub-depression, which has undergone two stages of hydrocarbon generation. The reservoir is dominated by weathered crust dissolution layers, with high-conductivity fractures and dissolution fractures as main reservoir spaces. Caprocks are thick dark mudstones of Es3 and Es4,with good sealing capacity. Migration pathways include two types: vertical migration along faults and lateral migration along unconformity surfaces. （3） The source-reservoir configuration relationship of buried hills in the study area has significant impacts on the reservoir formation. Paleogeomorphology and fracture density have controlling effects on reservoir quality. Faults and fractures are main migration channels for oil and gas. There are two types of oil and gas reservoirs,including “new source and old reservoir-lateral pinch out” type and “new source and old reservoir-buried hill top” type. The former is distributed in the central slope zone, where hydrocarbons migrate laterally from source rocks into buried hill reservoirs in contact with mudstones. The latter is distributed near large faults in the eastern slope zone, where oil and gas migrate vertically along faults to the top of the buried hill. （4） Compared with Shulu buried hill in Jizhong Depression, the study area exhibit an obvious double-layer structure of weathered crust, with lateral pinch out accumulation model as the dominant model and hydrocarbon properties being unitary. Five favorable zones are identified, among which Zone Ⅱ and Zone Ⅲ located in the central slope zone of the buried hill have optimal reservoir formation conditions and represent the most favorable exploration targets.

Key words: metamorphic buried hill, fractured reservoir, weathered crust reservoirs, source-reservoir configuration, new source and old reservoir, Archean, Binxian uplift, Dongying Sag, Bohai Bay Basin