方正断陷李家店次凹断裂特征及构造演化

FRACTURE CHARACTERISTICS AND TECTONIC EVOLUTION OF LIJIADIAN SUBSAG IN FANGZHENG FAULT DEPRESSION

前人对方正断陷的研究多以三维地震资料覆盖工区为主,很少研究二维地震工区。以方正断陷南部李家店次凹二维地震资料覆盖区为基础,对李家店次凹的断裂特征进行了分析。结果表明:断层剖面特征多为"y"字形、花状、台阶状等,断层平面组合特征呈现继承性规律变化;李家店次凹构造在白垩纪经历了早期裂陷成盆阶段、中后期回返抬升阶段2个演化阶段,在新生代经历了新安村—乌云组、达连河组的再次下沉阶段、达连河沉积末期的抬升阶段、宝泉岭组的稳定沉降阶段和新近系走滑拉分阶段4个演化阶段。该研究弥补了方正断陷整体性认识上的不足,对下一步油气勘探具有指导意义。

The previous studies on Fangzheng Fault Depression are mainly concerned on the 3D seismic-data-covered area,while the researches on 2D seismic-data-covered area are rather rare. Based on the 2D seismic-datacovered area of Lijiadian Subsag in the south of Fangzheng Fault Depression,the fracture characteristics of Lijiadian Subsag were analyzed. The results show that the fault profile features are mostly presented in Shape ＂y＂,flowerform,Shape step etc,and the characteristics of the fault plane combination show the inheritance variation; the subsag Cretaceous structures have experienced the following two evolutionary stages： the early rifting and basin formation stage and the middle and late returning and uplifting; and in Cenozoic era,the structures went through four evolutionary stages： subsided again for Xin＇ancun-Wuyun and Dalianhe Formations,uplifted in the late Dalianhe deposition,steadily settled in Baoquanling Formation and strike-slipped and pulled-apart in Neogene. The researches have made up the limitation on the whole understandings about Fangzheng Fault Depression and furthermore possess the guiding significance for the next exploration of the oil and gas.