走滑运动—三角洲的耦合控藏——以俄罗斯北萨哈林盆地为例

THE COUPLING OF STRIKE SLIP MOVEMENT AND DELTA DEPOSITION AND ITS CONTROLLING OVER HYDROCARBON ACCUMULATION: A CASE FROM NORTH SAKHALIN BASIN IN RUSSIA

基于对俄罗斯北萨哈林盆地构造演化及地层充填特征的基础地质特征分析和油气分布规律的总结,对盆地油气分布特征的主控因素进行了探讨。研究认为:盆地的油气分布在平面上具有油气田呈S—N向成带分布,从北向南具有'油减少、气增多'的特点;在纵向上,油气发现的层位具有'北上南下'的特点;在规模上,油气储量分布具有'陆小海大'的特点。油气成藏条件综合评价分析认为,油气分布主要受走滑断裂和三角洲发育的控制,具体表现为:走滑运动与不同时期的三角洲控制着烃源岩的展布,使得油气分布呈北产油南产气的特征;走滑运动和3期三角洲的迁移使得油气发现层位呈'北上南下'的特点;走滑断裂带控制了圈闭规模和保存条件,使得油气田规模呈'陆小海大'的特点。结合以上分析指出,北萨哈林盆地东部海域勘探程度低,含油气系统证实具有多期三角洲和多类型圈闭发育,是北萨哈林盆地具有较大勘探潜力的区域。

Based on the tectonic evolution,sediment filling characteristics and the distribution pattern of oil and gas fields in the North Sakhalin Basin of Russia,we discussed in this paper the main controlling factors of oil and gas accumulation.It is found that the spatial distribution of oil and gas fields in the basin is in a zoning pattern in north-south direction.Oil decreases while gas increases from the north to south.Vertically,oil and gas occur in higher horizon in the north but lower horizon in the south.On the scale of oil and gas accumulation,the fields on land are usually smaller than those in the sea.The distribution of oil and gas is mainly controlled by the coupling of strike slip faults and deltaic deposition.The strike slip movement and deltaic deposition in different period control the distribution of source rocks,which result in the distribution of oil in the north and gas in the south;The migration of the three stages of deltaic deposits with the strike slip movement caused the vertical oil and gas occurence,which is higher in the north and lower in the south.Strike slip faults are also the factor which controls trap scale and preservation conditions of oil and gas fields,making the oil and gas fields smaller on land but bigger in the sea.According to the above analysis,this paper suggests that the eastern area of the North Sakhalin Basin is more favorable for oil and gas exploration.