Structural Features And Hydrocarbon Prospect Analysis Of Qiedong Area In Kunlun Piedmont Zone

To identify the geologic and tectonic features of Qiedong area and discuss its hydrocarbon potential,631.1km of12CEMP sections,8141.8km2gravity and magnetic data, seismic, drilling and other geological data were collected, and lots of references were referred in this paper.According to the interpretation method of plane-section-plane, based on geophysical and geological data, using gravity, magnetic and electric techniques, integrated interpretation with geology, drilling and seismic data, demonstrating repeatedly from qualitative analysis to quantitative analysis, known to unknown, step by step.Combining conventional methods and special methods of gravity and magnetic data processing, one-dimensional and two-dimensional of electric data processing, constrained inversion of drilling data, establishing Geological-Geophysical model, integrated processing and interpreting gravity, magnetic and electric data, then estimate the tectonic features and oil/gas prospect of the study area.The major geological conclusions of the study area as follows:①The main part of this area is located in the North Kunlun step fault zone. Qimantage mountain thrusts to the basin by the North Kunlun fault F9, contacting with the basin. The step fault zone has thin cover, showing ladder lifting structure. This means the piedmont lake is always shallow and the slope is always in the lifting state.②Because of the long-term compressing environment, the faults are parallel to Laoshan, in NWW strike direction, with the characteristics of contemporaneous and long-term.③The main basement is Hercynian-Indosinian composite anticline fold. The step fault zone is divided into5secondary building units by relief intensity of the basement and the fracture assemblage features. It is higher in the South than the North, with the interphase structures between arched and valley areas.④Integrated analysis by12electric sections, surface geology and drilling data, the Upper Tertiary of the South step fault zone was nearly eroded, the maximum residual thickness is1900m, at Wanliang of the North.⑤Two hydrocarbon prospect areas were divided according to the conditions of petroleum geology and oil/gas resources and the analysis of local structures.