新构造运动与渤海海域上第三系大型油气田

THE NEOTECTONISM AND MAJOR NEOGENE OIL AND GAS FIELDS IN BOHAI SEA

在影响渤海海域上第三系大型油气田形成的诸多因素中,上新世-全新世的新构造运动起到用.渤海湾盆地"向心式”的演化规律(沉降、沉积中心由周围陆区向海域逐渐转移)以及晚第三纪以来盆地热流值的逐渐降低,使得海域的烃源岩生、排烃晚;上新世-全新世的新构造运动形成的众多上第三系圈闭为油气聚集提供了有利场所;大量晚期断层与控凹断层、不整合面及砂体相沟通,构成了油气运移的良好通道,并调整和控制了油气的最终成藏.依据构造位置和圈闭成因可将渤海上第三系油气藏划分为3种主要类型:凸起上的背斜型油气藏、凸起-凹陷边缘断阶带的滚动背斜型和断块型油气藏、凹陷中继承性构造和反转构造型油气藏.

Pliocene-Holocene Neotectonism has played a key role in formation of Tertiary oil and gas fields in Bohai Sea. A 'centripetal' evolution of the subsidence and sedimentation center and gradually lowering geothermal flux since Neogene have resulted in later hydrocarbon generation and drainage from source rocks in the Sea. The Neotectonism has created a lot of Neogene structures which can provide favourable places for hydrocarbon accumulation. A large number of late faults has intersected sag-controlling faults, unconformities and sandbodies, which may form excellent pathways for hydrocarbon migration and control final hydrocarbon accumulation. These Neogene oil and gas pools can be divided into three major types according to structural position and trap origin: anticlines in uplifts, rollover anticlines and fault blocks in fault-terrace zones between uplifts and sags, and inherited and inverted structures in sags.