Basin Structure Characteristics Analysis Of Zhanhua Sag And Chezhen Sag

Zhanhua sag and Chezhen sag are secondary structural units of Jiyang depression in Bohai Bay Basin, located in the north of Jiyang depression ,which have enrichment conditions for oil and gas in structural environment, but at present the cognition about basin geometry characteristics and area time otherness of Zhanhua sag and Chezhen sag is not clear, which limited exploration and development of oil and gas, so it is very important to analyse systematically by numbers basin geometry characteristics of Zhanhua sag and Chezhen sag while contrasting the sags and in search of otherness, starting with basin geometry and kinematics research.From the seismic interpretation of the research aera, this paper analysis the geometric characteristics of Che Zhan and Zhanhua sag, it is thought that the basins develop three faulting systems which are NE, NEE and NW trends since Cenozoic. Zhanhua sag is a rollover half graben which faulting south and overlap northward, there were expanding and expanding strike slip structural styles, buried hill structural styles developed in Guxi and Changdi-Gudong as well as the NW trend buried hill belts. Chezhen sag is a domino half graben which primary structural style is expanding structure, developed a spot of buried hill structural styles, the structure features of various structural belt in basin are different in a certain extent.Secondly, we distinguished uncomformable surfaces from a large amount of seismic sections and logs, and Zhanhua sag is divided into five structural layers, include Ek,Es4,Es3-Es2x,Es2s-Ed and N-Q, but Chezhen sag lost Ek. We ananlysis kinematic characteristic and dynamic evolvement process of the basin by using fault activity calculation and balanced cross section. It was thought that NW fault depressions developed in Ek, structure transformed in Es4, NE fault depressions developed in Es₃-Es₂^x, NE fault depressions become depauperizing in Es2s-Ed, depression basin developed in N-Q. Dynamical mechanism of this kind of otherness was analysed base research of basin evolution.Lastly, we analysis the influence of the baisn structure to the depositional filling, the sediment and subsidence center transferred from south to north as a whole. The spatio-temporal evolution of basin structure have influence on the sedimentary systerm, however, the influence has difference. It was thought that scattered fans developed in Ek at Zhanhua sag, alluvial fans and subsea fans developed in Es4,while deltas, deep sea fans and subsea alluvial fans appeared, subsea fans and deltas developed at large in Es3, deltas subsea alluvial fans become principal part in Es2, deltas subsea alluvial fans hold developed mostly in Es2-Ed, while fewness berm dams developed.