Research on the Formation Geological Conditions and Development Stages of Source Rocks in Linnan sag

Abstract

The study area is located in the Linnan subsag in the west of the Jiyang Depression of the Bohai Bay Basin. Its structural axis is in the NNE direction. It mainly develops four structural units: the Linnan slope zone, the Xiakou fault zone, the Linnan subsag zone and the central uplift zone. , The exploration area is about 1300 km2. The formation and evolution of the Linnan sag can be roughly divided into four stages: the Mesozoic fault depression, the slope of the Kongdian Formation-Upper Es4 deposition period, the fault depression during the Es3 Member-Dongying Formation deposition period, and the Neogene depression. During the formation of the sag, a complete Paleogene strata was deposited, which was divided from top to bottom into the Kongdian Formation, Shahejie Formation (which can be subdivided into four sections), Dongying Formation, Guantao Formation and Minghuazhen Formation , And formed multiple sets of source, reservoir, and cap rock assemblages. The Shahejie Formation is not only the most important source rock development interval in the Linnan Sag, but also an important reservoir rock and cap rock development interval. Various types of oil and gas reservoirs, especially lithological oil and gas reservoirs, are important exploration targets for increasing reserves and production in this area. The study of the geological conditions and development stages of the source rocks in the Linnan Sag is not only a basis for establishing a hydrocarbon accumulation model, but also a theoretical basis for oil and gas exploration. Therefore, it is very necessary to analyze the organic geochemical characteristics and oil and gas sources of the source rocks in the study area.