渤南低凸起变质岩潜山风化壳储层发育特征及控制因素

打开文本图片集

中图分类号：TE112；P618.13 文献标志码：A

Abstract：TheBZ26-6oilandgasfield，anewlydiscoveredbilion-ton-scaleburied-hillbedrockreservoirinBohai Sea，is characterized byalarge-scalereservoir system dominated bya weathering-crust hydrocarbon storage zone.By integrating drillng，seismic，loggng，andlaboratoryanalysisdata，thisstudyelucidatesthedevelopmentcharacteristicsoftheburiedhilledrock reservoirand identifies themaincontrollng factorsgoverning weathering-crustformation.Theresultsindicate thatthe metamorphicburied-hillreservoir isprimarilycomposedof metamorphicgranites，withdissolutionporesandstructural fracturesserving as the mainreservoirspaces.Verticaly，thereservoircanbedivided into three zones：aweatheredsandstone one，aweatheredfracture zone，andabedrock fracture zone.Theformationanddistributionoftheburied-hillweatheringcrustreservoirarejointlycontrolldbylithology，tectonics，weathering-leachingprocesses，andpaleogeomorphologyAbout 90% of the reservoir consists of felsic-rich metamorphic granites，providing a favorable material basis for weatheringcrust development.Multiphase tectonic movements generated extensivefractures within theburied hill，which notonlycontributed directlytoreservoir space butalsoenhanced dep-seateddissolution through fluidmigration.Weathering-leaching played acritical role，with weathering intensity decreasing downwardandoptimal reservoir qualityoccuring within 300m of theburied-hilltopsurface.Paleogeomorphologyfurtherinfluencedweatheringcrust thicknessanddistribution.High-elevation areasexperienced strong weatheringbut poor preservation，with thin weathered sandstone zones and moderatelythick weatheredfracture zones.Steep slopes developed moderatefracture zones，while gentle slopesand low-lyingareas providedfavorable conditions for the preservation of thick weathered sandstone and fracture zones.

Keywords：metamorphic rock buried hill;reservoir characteristics；weathering crust; maincontrollng factors；developmen tal patterns；BZ 26-6；Bonan low uplift；Bohai sea area

近几年，渤海海域在环渤中地区基岩潜山领域获得多个大中型油气田发现，基岩潜山油气藏成为渤海油田油气勘探重要的接替领域，已经引起越来越多的关注[1-3]。（剩余20866字）