渤海湾盆地渤中凹陷潜山及上覆砂砾岩显微图像数据集

A micrograph dataset of buried hills and overlying glutenite in Bozhong Sag,Bohai Bay Basin

渤海湾盆地东临胶辽隆起区,西接太行山隆起区,南北分别被鲁西隆起区和燕山褶皱带所限,总体上呈不规则的菱形,面积约20×104 km2,为新生代裂谷盆地叠加在前新生代克拉通盆地之上的大型叠合(或残留)盆地,前新生代基底发育大量潜山。鉴于渤海海域潜山基础地质研究程度较低,至今可以公开查阅的基础岩石学数据十分匮乏,重复的岩石学工作不断在进行。为此本文收集渤海湾盆地渤中凹陷太古界潜山变质花岗岩及其上覆古近系孔店组砂砾岩薄片204件,分为两大部分,花岗岩薄片61件,碎屑岩薄片143件。揭示了渤中19-6(即BZ19-6)构造带深层潜山储层是由太古界潜山变质花岗岩主体及上覆的古近系孔店组砂砾岩组成的泛潜山储集系统,形成砂砾岩孔隙带+潜山风化壳溶蚀裂缝带+内幕裂缝带+致密带的多层次储层结构,储层成因复杂、类型多样。本数据集记录了样品采集位置、地层时代、岩石名称。花岗岩部分显示潜山矿物组合以石英、长石、少量黑云母等暗色矿物为主,并且详细记录了裂缝期次和填充物类型,以及面孔率。碎屑岩部分记录了古近系孔店组砂砾岩颗粒成分、杂基含量等信息。通过系统的显微岩石薄片研究,明确了BZ19-6泛潜山储集系统岩性变化导致的裂缝差异性发育,识别了岩性流体的储层溶蚀改造效应,为渤海潜山油气的进一步勘探提供了基础岩石学数据。

The Bohai Bay Basin is bordered by the Jiaoliao uplift in the east,the Taihangshan uplift in the west,and limited by the Luxi uplift and the Yanshan fold belt in the north and south respectively.Overall,the basin is in the shape of an irregular rhombus,with an area of about 20×104 km2.The valley basin is a large-scale(residual)basin superimposed by a Cenozoic fracture on a pre-Cenozoic craton basin,where a large number of buried hills are developed.However,basic geological research on the buried hills in Bohai Sea has been understudied,which results in scarce publicly-accessible petrological data,and consequently,repeated petrological work.In view of this,our study collected 204 Archean buried-hill metamorphic granite sections and their overlying glutenite rock sections of Paleogene Kongdian Formation in Bozhong Sag,Bohai Bay Basin.They were then divided into two parts,61 granite sections and 143 clastic sections.It is revealed that the deep buried hill reservoir in the Bozhong 19-6(i.e.,BZ19-6)structural belt is a pan-buried hill reservoir system composed of the main body of Archean buried hill metamorphic granite and an overlying Paleogene Kongdian Formation glutenite,which formed a multi-layered reservoir structure consisting of glutenite pore zone,buried hill weathering crust dissolution fracture zone,and inner fracture zone tight zone,with complex reservoir genes and diverse reservoir types.The dataset records the sampling location,stratigraphic age,and name of the rock thin sections.The granite part shows that the buried hill mineral assemblage is dominated by dark minerals such as quartz,feldspar,and a small amount of biotite,and it also records the fracture period,filling type,and hole ratio.The clastic rock part records the composition of Kongdian Formation glutenite and the content of its miscellaneous base.A systematic study of the microscopic rock thin sections reveals a differential development of fractures caused by lithologic changes in the BZ19-6 reservoir system in the buried hills,and the impact of lithologic fluid on reservoir corrosion transformation,which provides basic petrographic data for further exploration of oil and gas in the buried hills of Bohai Sea.