渤中凹陷古近系石南断层活动性及其对油气成藏条件的控制作用

针对渤中凹陷石南地区古近系钻遇井稀少及烃源岩分布、储层类型及展布、油气的运移及油气藏类型模糊等问题,利用三维地震、钻井、测井和分析化验等数据,结合沉积背景,运用断层活动速率法详细研究了古近系石南断层的活动特征,并探讨了断层活动性与油气聚集的关系。结果表明:古近系石南断层活动性呈"弱-强-弱-强-强-最弱"的变化特点;沙河街组三段及东营组三段、东营组二段沉积期断层活动性强,是烃源岩发育期,而沙河街组一段-沙河街组二段、东营组一段沉积期断层活动性弱,是储层发育期,且东营组二段沉积期为强烈拗陷期,发育了大型的远源三角洲前缘沉积,亦是较好的储层发育期;断层活动性强的位置形成断层-背斜油气藏与断层-岩性油气藏,断层活动性弱的位置形成岩性油气藏及断层-岩性油气藏。

Activity of Shinan fault and its control on hydrocarbon accumulation in the Paleogene in Bozhong Depression

The Paleogene in Shinan area of Bozhong depression is encountered by only a few wells,constraining the understanding of its source rock distribution,reservoir type and distribution,and hydrocarbon migration as well as reservoir types.Based on integration of 3D seismic,drilling,logging and laboratory data and in combination with sedimentary settings,we studied the features of acitivity of Shinan fault in the Paleogene in Bozhong Depression and discussed the relationship between fault activity and hydrocarbon accumulation by using fault slip rate method.The activity of the Shinan fault features in regular change pattern of"weak-strong-weak-strong-strong-weakest".It was the strongest during the deposition of the third member of Shahejie Fm and the 2^nd and 3^rd members of Dongying Fm when source rocks were developed.It was weak during the deposition of the 1^st and 2^nd members of Shahejie Fm and the 1^st member of Dongying Fm when reservoirs were developed.In addition,strong depression occurred during the deposition of the 2^nd member of Dongying Fm when relatively good reservoirs were developed in the large distal delta front deposits.Fault-anticline reservoirs and fault-lithologic reservoirs occur in locations with strong fault activity,while fault-lithologic reservoirs and lithologic reservoirs occur in places with weak fault activity.