松辽盆地庆深气田营城组火山地层格架特征及储层地质意义

Volcanostratigraphy framework characteristics and its reservoir significance in QS Gas field,Songliao Basin,NE China

以庆深气田密井网区营城组火山岩为例,开展火山地层精细地层格架地质—地球物理综合研究,分析火山地层界面和充填单元的特征。XS1-XS6井区火山地层界面系统由3个喷发间断不整合界面、数十个喷发不整合和少量喷发整合界面构成。在XS1-XS6井区识别出5个火山机构和13个冷却单元。总体上该区火山地层具有由南向北、由东向西再向东迁移的特征。早期形成了厚度大、范围小的锥状火山机构1和2,以熔岩型冷却单元充填为主;中后期形成厚度中等、分布面积大的席状—盾状火山、喷发中心不明显的火山机构3、4和5,以碎屑岩型冷却单元为主。界面、流动单元或堆积单元共同控制高孔隙带分布位置,流动单元和堆积单元还控制储层的类型和规模;总体上火山地层界面可为油气勘探提供重要线索。

Based on short distance well pattern and high resolution 3Dseismic data in QS Gas field,Songliao Basin,NE China,we carry out a research on volcano-stratigraphy framework of Yingcheng Formation.The volcano-formation boundary system is consisted by overlapping 3 key eruptive interval unconformity boundaries(EIUB),tens eruptive unconformity boundaries(EUB),a few eruptive conformity boundaries(ECB)and intrusive contact boundaries(ICB).5volcanic edifices constrained by the 3 EIUBs are identified as bottom and top boundaries of volcanic rocks of Yingcheng Formation.Furthermore,13 cooling units constrained by the boundary system are also identified.The volcanostratigraphy shifts from southeast to northwest at first,and then shift to northeast.The volcanic edifices in the early stage are characterized by large thickness,small size and cone,such as the VE-1and VE-2,which are mainly consisted of the lava flows.The volcanic edifices in middle-later stage are characterized by small thickness,large size,and sheet-shield without obvious eruptive center,such as VE-3,VE-4and VE-5,which are mainly consisted of deposit units.The boundaries,lava flows and deposit units control the distribution of high porosity and permeability zone while the lava flows and deposit units control reservoir types and scales.The volcanostratigraphic boundary provides a very important mark for exploration.