远源缓坡型薄层细粒浊积岩沉积规律--以松南西斜坡大布苏地区青一段地层为例

以松南西斜坡大布苏地区青一段薄层细粒浊积岩地层为例，以高分辨率层序地层学和沉积学理论为指导，建立了五级层序的高精度等时地层格架，并用最大熵频谱分析进行验证。利用岩芯、测井和地震手段，总结了研究区浊积岩的沉积特征及与三角洲前缘沉积相的区别，通过单井、连井以及RMS振幅确定了坡折带的位置及浊积岩沉积分布规律，得出该区浊积岩属于三角洲前缘河口坝远源缓坡滑塌成因，为线物源、砂泥混合型。薄层细粒浊积岩沉积规律研究表明:①滑塌浊积体主要分布于基准面下降期，靠近层序界面，厚度较大，垂向上表现为叠加或与浊积水道呈互层，且向上厚度增大；②上升期浊积水道往往靠近层序界面，厚度较大，表现为“箱状”水道主体，下降期浊积水道靠近湖泛面，厚度较小，表现为“尖指状”水道侧翼；浊积水道随基准面上升厚度减薄，随基准面下降厚度增加；③浊积席状砂主要分布在较深水、最大湖泛面附近，厚度较薄，或表现为垂向上叠加，或与湖相泥岩、浊积水道侧翼及滑塌浊积体呈互层关系。勘探实践表明研究区薄层细粒浊积岩可以获得较高的油气产量。

Sedimentary Laws of Thin-layer, Fine-grain Turbidites of Distant-gentle Slope: A case from the 1 st member of Qingshankou Formation in Dabusu area of west slope, south Songliao basin

 Based on the study of high resolution sequence stratigrapghy and sedimentology, isochronic stratigraphy framework of high accuracy in fifth level has been established, and tested by the analysis of maximum entropy spectrum, a case study of the 1st member of Qingshankou formation in Dabusu area of west slope, south Songliao basin. Using cores, logging and seismic responses, sedimentary characteristics and differences with delta front deposits were concluded. With the analysis of single wells, connective wells amd RMS, the position of slope break belt and distribution law of turbidte deposites were verified. The turbidite deposits in this area belong to the origin of distant mild slope slumping of mouth bars in delta front subfacies, and were also attributed to linear source and mud sand rich type. The sedimentary law of thin layer, fine grain turbidites certificated that  ①slumps were mostly located in the falling period of base level cycles, near the sequence boundary, thick thickness, superimposed or interlayed with turbidite channels vertically, and thickening upwards. ②turbidite channels were usually near the sequence boundary, thick thickness, and conducted as mainbodies of boxing logs in the rising period. But turbidite channels were usually near the flooding surface, thin thickness, conducted as flanks of aciculate finger logs in the falling period of base level cycle. The thickness of turbidite channels was thinner with the rising of base level, and was thicker with the falling of base level. ③turbidite sand sheets were mainly distributed in deeper and near maximum flooding surfaces, thin thickness, superimposed or interlayed with lacustrine muds, turbidite channel flanks or slumps vertically.Exloration practices indicated that high oil reserves can be found in thin layer, fine grain turbidites of this area.