北部湾盆地涠西南凹陷W61潜山油气成藏条件分析

W61潜山区块已发现了岩性—古潜山风化带叠合型、岩性与古潜山风化带分离型和单纯的古潜山风化带型三类油气藏。W61潜山由于处在构造高部位 ,受多期构造运动影响 ,断层及不整合面发育 ,具有良好的油气运移通道 ,其西南生油洼陷内的流沙港组烃源岩生成的油气多沿此运移至潜山成藏。石炭系碳酸盐岩风化壳及其上覆的碎屑岩为主要的储集层 ,储集空间主要为裂缝、溶孔、溶洞及原、次生孔隙。区域盖层为流沙港组和角尾组厚层泥、页岩。在本区 ,古潜山风化带、岩性及断层的分布是决定潜山油气藏类型的主控因素

CHARACTERISTICS OF BURIED HILL OIL POOL OF W61 AREA IN WEIXI'NAN DEPRESSION, BEIBU GULF BASIN

Three oil or gas pool types, which are the super po sition and separation of lithology and buried hill weathering crust, and the pur e buried hill weathering crust, have been discovered in W61 buried hill area. Th e area is situated in structural culmination, and its faults and unconformities developed well, so its oil or gas from effective source rock of Liushagang Forma tion which belongs to the southwest A sag, can migrate to the buried hill and fo rm trap through these favorable migration pathways. Carboniferous weathering cru st sediments and its overlying elastic rocks are the main reservoir rocks. Frac tures, cap rock and pores, primary and secondary pores are the major preserving spaces.Liushagang Formation and Jiaowei Formation thick mudstone and shale are regional cap rock. In W61 area, the distribution of buried hill weathering crust , lithology and fault are the major controlling factors of oil or gas pool-formi ng type.