柴西南地区古近系—新近系井—震统一层序地层格架的建立

Construction of Paleogene-Neogene Drilling and Seismic Matching Sequence Stratigraphic Framework in the Southwestern Qaidam Basin

柴西南地区古近系—新近系是柴达木盆地最主要的油气勘探区和开发区,通过对54口钻井和录井资料的详细层序地层学的研究,对研究区古近系-新近系的干柴沟组—狮子沟组地层中识别出了一个初次湖泛面和六个最大湖泛面,将其划分为6个三级层序和17个准层序组,并对十条连井剖面进行了层序对比。在此基础上,对柴西南三维地震区切出了与前述的钻井连井剖面相同的连井地震剖面,并通过对地震剖面层序界限识别和划分,以及将钻井剖面上的层序划分结果投影到连井地震剖面中等方法,对钻井剖面和地震剖面的层序划分结果进行了对比和调整,使两者完全统一,建立了柴西南区古近系-新近系井—震统一的高精度层序地层格架,这为该区开展岩性油气藏勘探奠定了基础。

Paleogene and Neogene in Southwest Qaidam Basin are the most important oil and gas exploration and development strata of the basin. Based on the detailed sequence stratigraphy study of 54 drilling and logging data, a first flooding surface and 6 maximum flooding surfaces were identified in Paleogene-Neogene Ganchaigou and Shizigou Formations, and these surfaces can be divided into 6 third-order sequences and 17 quasi-sequence groups. Sequence correlation was done in 10 well-to-well profiles. In corresponding to these well-to-well profiles, seismic profiles were sliced in 3D seismic data, and sequence boundaries were also identified in the seismic profiles. Then the identifiedsequences from well-to-well profiles were projected on seismic profiles, through correlation and adjustment, high-resolution Paleogene-Neogene drilling and seismic matching sequence stratigraphic framework was constructed in southwest Qaidam Basin. This work may give insights to explore lithologic oil and gas reservoirs in this area.