松辽盆地北部青山口组重力流特征研究及其地质意义

为在陆相湖盆寻找有利勘探目标,在岩芯观察和沉积、构造分析的基础上,对岩芯观察资料、三维地震资料、钻井资料和测井曲线资料等进行了较为详细的研究。研究表明,松辽盆地北部青山口组发育广泛的湖相泥岩沉积,沉积相主要为三角洲平原、三角洲内前缘、三角洲外前缘、深湖-半深湖和滨湖。湖区发育大规模重力流沉积,该区发现的重力流沉积主要有滑动岩型、滑塌岩型、碎屑流型、浊积岩型等类型;重力流岩石学特征表明青山口组二段下部的重力流沉积,主要为滑动岩型和滑塌型,岩性主要以粉砂岩,泥质粉砂岩,粉砂质泥岩薄互层为特征,局部含油或有油迹;而青山口组一段顶部的重力流沉积,主要为碎屑流型和浊流型,岩性上以粗砂岩、粉砂岩、粉砂质泥岩、泥岩的薄互层为主。初步探讨了重力流的发育和控制机制,分析表明青山口组重力流沉积是湖区的有利储层区域,英台大安地区为最有利储层。该研究对深入了解湖相储层特征起指导作用。重力流沉积勘探在松辽盆地还处于探索阶段,其研究为在大型陆相湖盆中寻找新的有利勘探目标奠定坚实基础。在陆相湖盆中研究深水重力流沉积,对沉积学研究具有推动作用。

Characteristics of Gravity Flow Sediment and Its Geologic Significance in Northern Songliao Basin

In order to find the favorable exploration target, based on cores observation and sediment, structural analysis, the application of 3D seismic data, drilling well data and well-logging data, the detailed research has been carried out. Lacustrine mudstones extensively developed in Qingshankou Formation of the northern Songliao Basin. The mainly sedimentary facies include delta plain, the deltaic front, outside the deltaic front and lacustrine sediments. Based on 3D seismic data, drilling core observation, well logs and other data, large-scale gravity flow deposits were found in the study area. Sliding rock, rock slump, debris flow, turbid flow are four types of gravity flow in the Qingshankou Formation lacustrine facies area. This article studied the petrography of gravity flow, particle deposition characteristics, and the vertical distribution characteristics. Through the study on the lower part of theⅡmember of Qingshankou Formation, it was found that the main rock types are slumping rock and slide rock. Main lithologies are thin interbedded, silt sandstone, argillaceous sandstone, and silty mudstone. Some regions contained few oil or oil stains. Main lithologies are thin interbedded, silty mudstone, coarse sandstone, mudstone, siltstone and mudstone, at the top of Qingshankou Formation deposits are debris flow and turbidite flow deposition. It acts as a guiding role for further exploration in Songliao Basin with development and control mechanisms of gravity flow. Through analysis by single well cores, logging curves, distribution characteristics, developmental horizontal of gravity flow were described in Ⅰ,ⅡMembers of Qingshankou Formation, this study sets a guide for in-depth understanding of lacustrine sediments. Exploration of gravity flow deposits in the Songliao Basin is still in the exploratory stage, its significance lies in looking for new favorable exploration sites, and found a solid foundation for research on deep water sedimentary gravity flow studies in large continental basin.