| The Yangwuzhai structural belt is located in the southern part of Raoyang Sag of Jizhong Depression. With a complex geological structure, which is necessary to carry out additional exploration and appraisal research. This paper focus on the system characteristic evolution and fracture structure of the Yangwuzhai structural belt. Aiming at related problems existing in old oil-field structure research, make full use of present data, on the basis of previous studies, through a variety of scientific methods including key wells stratigraphic correlation, fine 3D seismic interpretation, tectonic evolution history analysis and so on, while research corresponding fault systems, further rationalize the fault combination, summarize the structure characteristics, has resulted as an instruction basis for the guiding of oilfield development.With the completion of stratigraphic division and correlation of key wells, there are some defined results have come out, two sets of first-class marker layers( “W” type low resistance mudstone layer in the bottom sediment of Es1 bottom member and special lithologic section on the top of Es3 member), two sets of second-class marker layers( "thin neck" shape mudstone on the top of Es2 member and special lithologic section of high resistivity base value clip bayonet and high resistance on the top of Es3 member) and a number of auxiliary marker layers.By the means of seismic data splicing from multiple work area, it is possible to analysis the relationship between regional tectonic setting and structure, evaluate structural formation mechanism: the research area, which located in the southeast part of Raoyang Sag, lies in structural transfer zone, influenced by the bulges of three different around stress directions. In the east, Xianxian County uplift formation-north lifting south dipping; in the west, Gaoyang-Shenze low uplift formation- north dipping south lifting; in the south, Xinhe uplift strata- west dipping East lifting. The detachment movement of two giant uplift plates(Xianxian, Gaoyang-Shenze plate), is the basic factors of Southern Raoyang Sag’s large detachment gliding structure, furthermore, the study area lies in the southern district of above-mentioned region. Different structural features of the Paleogene, Neogene system, is a product of different tectonic activities of two blocks in detachment process of the tertiary period.Combined with the structural study of mechanism and fracture formation mechanics, fine 3D seismic interpretation has been realized by the use of multiple seismic attributes.The major fault in the research area includes Xianxian County fault, Sunhu- Yangwuzhai faults, Liuchu- Huangpucun fault, mainly developed "Y" type, "horsetail" type, faulted terrace type fault combination. The East-West differentiation of Yangwuzhai is clear, which shall be divided into three structural zones, namely the Yangwuzhai West monocline zone( north lifting south dipping), central anticline zone and east trough east steep zone. This area is divided into three local tectonic zones from north to south: Yangwuzhai subject anticline zone, northern fault nose structure zone and southern fault nose structure zone. From related analysis of the timing of fault activity, Sunhu- Yangwuzhai structural belt has faulted with multiple periods, herewith three episodes of fracture development in total. Fault development period and tectonic movement in this area is closely related. The northern part of the Yangwuzhai fault nose structure zone is a three tectonic stacking area, with specific characteristics of fault development, structural fracture, ensure it to be a favorable oil and gas accumulation zone. |
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