Synthetic Seismic Data Interpretation And Research On Structural Features In The South Of Urxun Depression

Wuerxun depression is a Mesozoic Era -Cainozoic Era Fault depression in the middle of Hailaer-Tamuchage basin.On the basis of the predecessors'study, this paper studies the structural interpretation of seismic data for the southen area of Urxun sag. By the application of structural Geology, Sequence stratigraphy theory, we can interpret the new 3D seismic data more accurate. we can identify the regional unconformity interface and trace it exactly. And then establish the isochronal stratigraphic frame work; we analysis the tectonic pattern and the characteristics of the research area.Using a new methord we establish the 3D velocity field and extract the average velocity. Convert isotime map to isodepth structural map.By study the structural map and seismic profile we can study the distribution of the faults that control the formation of the sag;we analysis the tectonic pattern and the characteristics of the tectonic in different evolutionary stages and predict the beneficial hydrocarbon accumulation area.According to 3 important regional unconformity interfaces repersent on seismic profile T₅,T₂₂,T₀₄ research area can be divided into faulted basin sag basin and its transformation stractural layer 3 stractural layer. The regional structure has the characteristics of east-west dividing zones and south-north dividing blocks.In the northern area structural form of development is controled by Wuxi fault while in the sourthern area structural form of development is controled by BaYantala fault.In the northern part it is a half graben,Its west fault east overlap ;in the southern part it is a half graben,Its south fault north overlap. The distribution of formation is that the west part is thicker than the east,while the south part is thicker than the north. The main structural style in researth area is stretch style, combined with shear structure . stretch style developed in the northern area on both fault area and slope area; shear structure developed in Bayantala area.The development of structure analysis indicates that the research area have gone though 4 stages :intensity fault depression ,fault depression,fault sag and fault sag atrophic. Structural pool and structural lithologic composite oil pool are the main reservoir form. The structure controls the hydrocarbon accumulation,in this area oil-gas mainly accumulate in the local structure zone.Faults worked as oil and gas migrating channels during fault opening.The development of structure and fault is the important factor to the hydrocarbon accumulation.