Structral Features And Hydrocarbon Accumulation Of Shenxian Sag Of Jizhong Depression

Shenxian Sag belongs to the secondary tectonic units in Central Hebei Depression.The sag,which is located in the southern part of the depression and a part of half-graben group of northwestern Bohai Bay Basin of the North China Plain,is formed under Dextral transtensional tectonic stress after the transfomation between the Paleo-Asiatic tectonic domain of North China and Circum-Pacific tectonic domain.Shenxian Sag because of the Jiuchengbei fracture,Hengshui fault and Hubei fracture under common control,the formation,is a typical asymmetric double fault depression,developing lots of buried hill reservoirs.This thesis,based on theory of modern tectonic geology,using various techniques such as seismic interpretation of typical sections,strutural analysis,balance profile reversion and comprehensive study of hydrocarbon accumulation condidtion,get the following points:1?Analyzes structral features and reservoir forming conditions of Shenxian Sag and finds taht the main structural framework of the sag is influenced by extension stress and it's the product of tectonism occurred in Cenozoic which inherited the structural features of antique basement.2?The structural assemblage of Shenxian Sag,which can be devided into five structural system,Shenze-Liucun low uplift,Hezhuang-Shenxi buried hill belt,Baisongzhuang sag belt,Shennan anticline belt and Yuke anticline belt,has obvious zonation.The main structural framework of the sag is controlled by major fracture,and the main structural trace is in WS-NE.3?Cenozoic is the main accumulation period in which the area has undergone three tectonic stages:faulted period,depression period and regional thermal subsidence.4?Source rock of number 1,2 and 3 of Shahejie formation produced petroleum after burial metamorphism,and then accumulated in number 1 of Shahejie formation and Dongying formation of Cenozoic and buried hill basement because of the sealing and the vertical and lateral migration of fractures,which formed the main structural reservoirs and buried hill reservoirs.Through systematic study on the structural deformation and tectonic evolution of Shenxian Sag,and the analysis of structural control and reservoir,it has certain guiding significance to guide the exploration of oil and gas in the next step.