Abstract:

Shenxian depression is located in the center part of Jizhong Subbasin, North China, with extremely complicated structures and diverse sedimentation systems. There are many different recognizations of the classification of hydrocarbon traps (particularly stratigraphic trap) and their distribution in the past years, which has restriced the accurate hydrocarbon exploration in such kind of complicated faulted depressions. Five structure zones can be defined in Shenxian depression and each has its particular sedimentary pattern that results in different trap types. Four major types and 8 subdivided trap types of petroleum trap, such as structural trap, lithologic trap, stratigraphic trap and buried hill trap etc., were summarized in this paper, which had responses to the structuralsedimentary patterns in this area. Structural trap mainly composed of fault block and fault nose had a wider distribution scale and concentrated in bulges of the secondary structural zones, mainly in Shennan anticline and Yuke anticline. Buried hill trap mainly occured in Hezhuang-Shenxi buried hill zone and Shenze-Liucun low bulge of the northern gentle slope belt. Lithologic and stratigraphic traps mainly existed in two flanks of buried hill zone and Shennan anticline and Baisongzhuang trough in the south, which responded to lenticular sandy conglomerate, updip sand body and tectonic setting in these areas. Therefore, it can be concluded that structural-stratigraphic composite petroleum reservoirs should be more important in the future hydrocarbon exploration in Shenxian depression.

Key words: Shenxian depression, petroleum trap type, lithologic-stratigraphic trap, structural-sedimentary pattern