渤海海域辽中凹陷走滑断裂分段性及其对油气成藏的影响

Strike-slip Fault Subsections and Its Influence on Hydrocarbon Accumulation in Liaozhong Depression of Bohai Sea Area

渤海海域辽中凹陷目前已发现的4.2×108 m3油气地质储量90%以上分布于走滑断裂带。根据走滑断裂的平面特征、剖面特征以及活动强度将其分为北段、中段和南段,其中中段走滑活动最为强烈,走滑特征明显,北段和南段相对较弱。走滑断裂利于烃类的生成和排出;走滑断裂形成了不同类型的走滑坡折带,控制了砂体的展布;走滑活动产生的一系列张性断层形成了不同样式的油气输导体系;沿走滑断层走向形成了一系列大规模的圈闭群,受右旋走滑挤压应力的影响,这些圈闭封堵性好,有利于油气的大规模成藏。

Ninety percent of 4.2×108m3 oil and gas reserves was distributed in the strike-slip fault zone of Liaozhong Depression in Bohai Sea,thus the research on strike-slip faults was of great significance.Strike-slip fault was divided into the north section,the middle section and the south section according to its plane features,profile features and activity features,among them the activity of the middle section was the strongest with obvious strike-slip features,while the north and the south sections were relatively weak.Strike-slip fault is favorable for hydrocarbon generation and discharge.It forms different slop-breaks and controls sand distribution.Along the faults a series of large scale of traps are created,the strike-slip activity forms different oil and gas transportation systems.Lots of traps formed along the fault strike of the strike-slip have good sealing and is favorable for large-scale hydrocarbon accumulation which is influenced by the right rotation compressive stress.