伸展构造背景下白云凹陷走滑断裂特征及其油气地质意义OA

To clarify the development characteristics,formation mechanism and hydrocarbon-controlling effect of strike-slip faults in the Baiyun Sag under the extensional tectonic setting,based on high-precision 3D seismic data and combined with the regional plate dynamic background,the paper systematically identified the strike-slip faults in the study area by integrating structural analysis,seismic profile interpretation and fault combination analysis methods.The paper analyzed their planar and profile structural characteristics,and discussed the tectonic back-ground,deformation mechanism of strike-slip faults and their controlling effect on the differences of hydrocarbon accumulation.The strike-slip faults on the northern slope of the Baiyun Sag developed in the Cenozoic extensional-strike-slip composite tectonic environment,and are jointly controlled by the South China Sea spreading,plate cou-pling and the evolution of regional stress field,forming a fault system dominated by dextral strike-slip.On the plane,the faults are predominantly NWW-striking with associated NEE-striking secondary faults,developing typi-cal dextral strike-slip assemblages such as en echelon,horsetail and anti-"S"patterns,and showing the distribu-tion characteristic of"zoned as a whole and differentiated in segments".In the profile,the"Y"-shaped flower-like structure is the core symbol,with the vertical zonation of"deep shearing and shallow extension"and the in-herited characteristic of"early extension followed by strike-slip activation".The deformation mechanism of faults is controlled by the inheritance of basement structure,the mechanical properties of lithosphere and the superposi-tion of stress field,experiencing two evolutionary stages of extension in the rifting period and strike-slip activation in the post-rifting period.Controlled by fault structures,two types of core traps,anticlinal fault trap and fault block trap,are mainly formed in the study area,among which the anticlinal fault trap controlled by reverse faults is the most favorable unit for hydrocarbon accumulation.