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

Key words: 
• Songliao Basin /
• gravity flow /
• sediment characteristics /
• geologic significance

Abstract: 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.