| Many oilfields have been found such as JZ20-2, JZ25-1/S in mid-north Liaoxi low uplift, where was one of the most important places of oil-gas production. The Dongying formation, Shahejie formation and Archaean buried hill are the main petroliferous formations. The Shahejie formation is chosed as the priority in this paper.However, there are some primary petroleum geological problems in this region, such as the source of the existing hydrocarbon, the hydrocarbon filling periods and accumulation process still leaving unsolved. And these problems restrain the exploration steps, and more they have become the restrictions to the hydrocarbon exploration.For this reason, this paper choose Liaoxi low uplift and its adjacent sags as the target,and try to settle these puzzles mentioned above with the assistance of modern theories of geochemical and petroleum geology, strategies of 3D seismic interpretation, basin molding as well as fluid inclusions analysis. Under the direction of these theories, integrated analysis that consist of hydrocarbon-source correlation, transporting-conducting system analysis, reservoir-forming dynamic analysis and reservoir-forming periods analysis are conducted, and based on which the mechanism of hydrocarbon transportation in Liaoxi low uplift region is constructed. This study is of great practical significance to the understanding of the hydrocarbon accumulation process of the uplift as well as to taping its great exploration potential, at the same time, it has positive effect to enrich and develop the theories of the petroleum generation, migration and accumulation.This paper contrasts, oil of mid-north part of Liaoxi low uplift and hydrocarbon source rocks of adjacent sags are analyzed synthetically, the result indicates that the oil of JZ25-1/S oilfields has the same kinds of sterane and terpane as the hydrocarbon source rocks in Liaoxi sag, which has the characteristics of mid-high content of gammacerane, high content of 4-methylsterane, regular sterane C27, C28, C29 has the bias-V characteristics of C27>>C28C28>C29, all these confirm JZ20-2 oilfields accumulated hydrocarbon from two different directions. As a whole, hydrocarbon in Liaoxi low uplift is accumulated from two different directions and the quantities come from each direction are of great difference.The transporting-conducting systems are composed of faults, sandbody and unconformity. Multi faults composed several structural styles such as dip fastigium terrace, Y-type faults group, downthrown terrace caused by boundary faults and positive flower structure. The structure styles of faults group made a critical function to secondary oil migration and oil redistribution. Sandbody and unconformity provide an important pathway for oil lateral transporting-conduction. Based on the coupling relationship of faults, sandbody and unconformity, the transporting-conducting system can be divided into three different types:â‘ fault conducting system,â‘¡cascade conducting system,â‘¢fault-unconformity-sandbody compounded conducting system. Three kinds of conducting systems provides pathway for oil migration, also they influence the types of oil-gas accumulation.Based on the analysis of transporting-conducting systems and types of oil-gas accumulation in JZ25-1/S and JZ20-2 oilfield, we conclude 4 kinds of matching relationship of them:â‘ Z-type transporting-conducting systems form massive oil-gas reservoir,â‘¡T-type transporting-conducting systems form massive or layered reservoir,â‘¢cascade conducting systems form layered reservoir or lithologic oil reservoir,â‘£fault-unconformity-sandbody transporting-conducting systems form layered or massive reservoir.The burial history and geothermal history of some wells in JZ25-1S oilfields are reconstructed firstly and then with the combination of homogeneous temperature analysis of fluid inclusions from productive reservoir formations, periods of hydrocarbon charging are determined. The analysis of hydrocarbon accumulation period indicated that the oil of JZ25-1S oilfield has a single and relatively earlier hydrocarbon charging and accumulation period. The accumulation period of the Shahejie formation in JZ25-1S oilfield is formed between 20-24Ma which corresponds to the end of 1st menber of dongying formation sedimentary period.
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