南美奥连特盆地16区块构造沉积特征及石油地质评价
The tectonic-sedimentary character and petroleum geology of block 16 in Oriente basin
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摘要: 以该盆地中心16区块为例,分析了其构造-沉积发育史及石油地质要素。研究表明该区前白垩系为断陷-裂陷盆地,白垩系为稳定的被动大陆边缘,新生界为前陆盆地。将主要目的层白垩系划分析5个层序,主要是河流-受潮汐控制的河口湾、三角洲-大陆架沉积,海平面相对升降变化决定了沉积体系的时空演化进而决定生储盖配置。含油气系统主力烃源岩为白垩系浅海相泥页及灰岩。产层为白垩系的河流相、海陆交替相和海相砂岩(NAPO组和HOLLIN组),其中,HOLLIN组和M段为低位期底积层,分布广泛,为主要侧向运移输导层。海陆交替相的潮汐水道砂-滨岸砂坝-障壁砂坝为主要储层,断层控制水道砂岩分布,来自断层的烃类与厚层优质砂岩及浅海泥岩、泥灰岩形成良好生储盖配置,斜坡带走滑断层和山前带逆冲断层为垂向输导层。盖层(亦为烃源岩层)为白垩系各旋回海侵期页岩或(泥)灰岩,稳定,封盖性好。晚白垩纪-渐新世(早安第斯期)为生排烃高峰期,中新世以后形成的圈闭不利于捕集油气。Abstract: Oriente basin of Ecuador is one of the most productive oilfield of the South America, Sub-Andean basins.At present Seven oilfield have been discovered in block 16.This article analyzed its tectonic and sedimentary history and it can be divided into three stages:pre-Cretaceous, Cretaceous and post-Cretaceous.Cretaceous include 5 sub-sequences and the main sedimentary facies are fluvio-deltaic (firth) and marine.Relative sea level eustasy controlled space-time change of sedimentary system and play.Neritic shale and limestone are the main source rocks of petroliferous systems and fluvio-deltaic and marine sandstones are the main productive formations.HOLLIN & M formations are main lateral migration paths, strike-slip fault and thrust fault are vertical migration paths.Hydrocarbon generation and migration peak occurred in Late Cretaceous-Oligocene.
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