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西藏它日错地区是中特提斯的一个重要深坳陷区 ,发育了巨厚的下白垩统海陆交互相和浅海相碳酸盐岩沉积 ,其中多巴组厚度超过了 15 0 0 m,主要沉积相类型包括陆源碎屑潮坪相、碳酸盐浅海、水下浅滩、混合沉积过渡带等。在它日错一带形成坳陷中心 ,主要物源从南、西南方向进积。多巴组中的烃源岩主要为浅海相灰岩 ,向它日错方向增多、加厚 ,有机质类型为混合型 ;可能的储集岩是浅滩相介壳灰岩、浅海相泥晶灰岩及潮坪相砂岩 ,裂隙是其主要的储集空间 ;而潮下带泥岩则可成为有利盖层。垂向上由于多旋回叠加 ,具有较好的生储盖组合 ,但所发现的烃源岩厚度较薄是其不利因素。
The Tibet-Tibet rift region is an important deep depression in Central Tethys. It developed thick Cretaceous marine-continental interaction facies and shallow marine carbonate sediments. The thickness of the Dooba Formation exceeds 15 0 m, The main types of sedimentary facies include terrigenous tidal flat facies, carbonate shallow sea, underwater shoal, mixed sedimentary transition zone and so on. In the center of its depression, the main source of sediment from the south and southwest into the plot. The source rocks in the Dooba Formation are mainly shallow marine limestones, which increase toward the Nipponbare and fault, and are thick and have a mixed type of organic matter. The possible reservoir rocks are shoal facies intercalated limestone, shallow marine mudstone, Tidal flat sandstone, fractures are its main reservoir space; while the subtidal mudstone can become a favorable cover. Due to multi-cycle superimposition in the vertical direction, it has good reservoir-cap assemblage, but the thin source rocks are found to be unfavorable factors.