双城地区构造演化特征及其对油气聚集的控制作用

Structural evolution characteristics of Shuangcheng area and its control effect on oil and gas accumulation

为了有效认识双城地区构造演化对油气成藏过程的控制作用,本次研究利用新三维地震资料,分析断裂特征及典型构造,研究形成机制,探讨构造形成期次与成藏期的匹配关系,明确勘探方向。结果表明,双城地区经历了营城组末期挤压、泉头组末期走滑和嫩江组时期抬升三期改造作用。其中,泉头组末期走滑作用形成了一系列的左行走滑构造,形成了以NNE、NW向断裂为主的一组共轭断裂,且在走滑构造带内部的不同方位具有不同的次级应力,形成一系列走滑伴生构造,兼具张性、压性的不同性质,其中NNE向断裂具有压性应力性质,与其伴生均为正向构造,而NW向断裂为张性应力性质,与其伴生均为负向构造。通过热史模拟表明双城地区在青山口组末期进入生烃高峰期,晚于泉头组左行构造形成时期,结合构造性质和成藏条件,明确了三个NNE向构造带为近期重点勘探方向。

In order to effectively understand the control effect of structural evolution in the process of oil and gas accumulation in Shuangcheng area,new 3D seismic data were used to analyze fault characteristics and typical structures,study the formation mechanism,discuss the matching relationship between structural formation period and reservoir forming period,and clarify the exploration direction.The results show that the Shuangcheng area has experienced three stages of transformation:compression at the end of Yingcheng formation,strike slip at the end of Quantou formation and uplift at the end of Nenjiang formation.Among them,in the end of Quantou formation the strike-slip effect is great for the study area,a series of left-lateral strikeslip structures were formed,and conjugate fractures were formed in NNE direction and NW direction.There are different secondary stresses in different directions within the strike slip structural belt,forming a series of strike slip associated structures with different properties of tension and compression.The NNE direction faults have compressive stress properties and their associated structures are positive,while the NW direction faults have tensional stress properties and their associated structures are negative.Through thermal history simulation,Shuangcheng area entered the peak period of hydrocarbon generation at the end of Qingshankou formation,later than the left lateral structural formation period of Quantou formation.Combined with the structural properties and reservoir forming conditions,three NNE trending structural belts were identified as the key exploration direction in the near future.