断层对南堡凹陷潜山油气藏的控制作用

断块型潜山油气藏是渤海湾盆地的一种重要油气藏类型，断层对该类油气藏具有重要的控制作用。为了揭示断层对南堡凹陷断块型潜山油气聚集与保存的作用，利用三维地震、钻井、测井等资料进行断层面形态的刻画、断层封闭性的计算及断层对储层改造作用的分析，重点剖析了南堡凹陷内5条断层对油气的优势运移通道、油气保存、油气的储集空间等方面的控制作用。研究结果表明：①油气的运移方向受断层面形态的控制，汇聚型输导体系有利于油气的运移，且断层面曲率大的部位试油中可获得较高的产能；②成藏期后断层的启闭系数控制着油气的保存及现今的含油气性，潜山顶部的断层启闭系数小于1时，断层纵向封闭好，油气保存条件好，后期含油气性高，大于3时，断层纵向封闭差，油气向浅部运移；③断层改造潜山储层的储集性能主要体现在裂缝的差异性分布，储层的裂缝密度与其距二级断层的距离呈现出较好的负相关性，且在一定程度上储层产能随裂缝密度的增加而增大。

Control of faults on hydrocarbon accumulation of buried hill reservoirs in the Nanpu Sag,Bohai Bay Basin

Buried hill reservoir of fault-block type is one of the important reservoirs in Bohai Bay Basin and its formation is significantly controlled by faults.In order to study the control of faults on hydrocarbon accumulation and preservation in buried hills of fault-block type, various data including 3D seismic, drilling and logging data were integrated to describe the geometry of fault planes, calculate the sealing capacity of faults, and analyze the control of fault on reservoir modification.The focus of analysis was put on the control of five major faults on the dominant pathways of hydrocarbon migration, preservation of accumulated hydrocarbons and the reservoir space for hydrocarbons.The following understandings were obtained:(1)The migration of hydrocarbons was controlled by the geometry of fault plane, carrier systems of convergence type were favorable for migration of hydrocarbons, and the section with heavy curvature could obtain high yield;(2)The sealing properties of faults after the hydrocarbons accumulation controlled the preservation of accumulated hydrocarbons and current oil-gas potentials.When the fault opening index (FOI) of faults on top of buried hills is less than 1, the vertical sealing capacity of the faults is good, the sealing conditions are good and the oil potential is high in later stage.When it is over 3, the vertical sealing capacity is poor and hydrocarbons migrate upwards to the shallow parts.(3)The modification of buried hill reservoirs by faults is reflected by the differential distribution of fractures.There is a negative correlation between the fractures density and the distance to the second-grade faults.To some extent, there is a positive correlation between production capacity and the fracture density.