塔里木盆地满加尔凹陷西北缘上奥陶统铁热克阿瓦提组海相砂体类型与储集性

通过对羊屋2井、跃南2井、吉南1井等5口井岩心的精细描述、单井沉积微相与测井相分析及350 km地震剖面解释，认为在满加尔凹陷西北缘上奥陶统铁热克阿瓦提组海相砂泥岩沉积地层中发育5种重要的海相砂体，即滨岸（临滨-前滨）砂体、内陆棚沙脊砂体、内陆棚沟槽砂体、风暴砂体与潮道砂体。在等时地层格架内，研究区西部羊屋与哈得井区，铁热克阿瓦提组最底部分布着具有正韵律特点的、发育海侵砾岩与冲刷面的内陆棚沟槽砂体，其上为正反韵律均有且冲刷面不发育的较细粒内陆棚沙脊砂体，上部则是发育平行层理和冲洗交错层理的具明显反韵律特征的滨岸（临滨-前滨）砂体，顶部发育非均质性较强的风暴层砂体。在东部的吉南井区，下部发育内陆棚沙脊砂体，上部发育潮下带潮道砂体及潮间带砂坪沉积。受奥陶纪末期全球海平面下降影响，砂体分布范围逐步增大。铁热克阿瓦提组海相砂岩储集体以次生孔隙为主，非均质性比较强，导致储集层非均质性的主要原因是不均匀胶结作用、溶解作用以及局部发育有裂缝。对比5种类型海相砂体的储集性，按优差排序依次是内陆棚沙脊砂体、滨岸（临滨-前滨）砂体、内陆棚沟槽砂体、潮道砂体与风暴沉积砂体。
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Marine sandbody types and reservoirs in the Upper Ordovician Tierekeawati Formation in northwestern Manjiaer Sag, Tarim Basin

Central Laboratory of Geological Sciences，Research Institute of Petroleum Exploration and Development，PetroChina，Beijing100083
Five types of marine sandbodies were identified in the marine sandy mudstone deposits of the Tierekeawati Formation in northwestern Manjiaer Sag based on detailed analyses of 5 wells including Yangwu 2， Yuenan 2 and Jinan 1， combined with microfacies analyses of single well and interpretation of over 350 km seismic profiles. They are shoreline， inner shelf ridge， inner shelf ditch trough， storm and tidal channel sandbodies. Ditch trough sandbodies with transgressive conglomerate and flooding surface at the basal part were developed at the bottom part in Yangwu and Hade areas in the west of the study area which was characterized by normal rhythm. Above it， the inner shelf ridge sandbodies with normal and reverse rhythms and no development of flooding surface. The top part is dominated by shoreline sandbodies with development of paralleling bedding and cross bedding and a reverse rhythm. The storm sandbodies with a strong heterogeneity were developed on the uppermost. In Jinan well area in the east of the study area， inner shelf ridge sandbodies were developed in the lower part， tidal channel sandbodies and tidal deposits were developed in the upper part. The distribution range of sandbodies gradually expanded with the influence of global sea level falling during the Late Ordovician. The marine sandstone reservoir in the Tierekeawati Formation is dominated by secondary pores with a high heterogeneity due to the inhomogeneous cementation， dissolution， and locally developed fissures. Reservoirs are ranked by their properties from good to poor ones as: inner shelf ridge， shoreline， inner shelf ditch trough， tidal channel and storm sandbodies.
Tarim Basin|Upper Ordovician|Tierekeawati Formation|marine sandbody|reservoir property
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Gao Zhiyong was born in 1974. Now he is an engineer of Research Institute of  Petroleum Exploration and Development，PetroChina and is mainly engaged in researches of sequence stratigraphy and sedimentology. E-mail:gzybox@163.com.