构造活动对渤中34区块油气成藏的影响

渤中34区块发育有不同期次不同走向的伸展断层和走滑断层，构造十分复杂，给该区块油气勘探工作带来一定的难度。通过对研究区地震资料进行构造解释，结合其他地质资料，深入研究渤中34区块的构造演化过程及其对油气成藏的影响，认为：①受构造运动控制的汇水中心控制沙三段、东下段和明下段深湖相-半深湖相烃源岩的分布,新构造运动快速沉降-充填以来，烃源岩快速埋藏，3套主力烃源岩都进入生油高峰期；②孔店组缓慢裂陷和快速拗陷时期，沙一段、沙二段拗陷时期，东上段裂陷-拗陷转换时期，馆陶组和明下段第二次裂后热沉降时期，分别沉积具有不同沉积相特征的储集砂体,裂后二次热沉降沉积的泥岩厚度大，形成良好的盖层；③压扭形成的背斜和张扭形成的牵引构造可以形成构造圈闭，河道砂与泥岩呈指状交错，泥岩中夹透镜状砂体能够形成岩性圈闭；④新近纪凹陷的生烃期、排烃期与断层活动有良好的匹配关系，大大提高油气的运移效率，同时也可能造成油气的散失，因此要形成好的油气藏，必须具备有利源控条件；⑤晚期构造伴生的EW向断层切割早期形成的NE向断层形成断层网，沟通不整合面，使油源和储层有效连通,断层幕式活动，活动时作为油气运移通道，关闭时阻碍油气运移；⑥该区油气成藏有2种重要模式，一种是油气通过深切烃源岩或“中转站”的大断层直接垂向运移，另一种是油气通过次级断层与砂岩输导层进行阶梯状运移。

Influence of Tectonic Activity on Reservoir Formation in the Bozhong34 Block

There are many tensional faults and strike-slip faults of different time and different strikes in the Bozhong34 block,the complex structural background makes the petroleum exploration difficult.In this paper,based on the interpretation of structure through seismic data as well as geological data,we discuss the evolution processes of tectonic activities and their influence on the petroleum accumulation.The results show as follows:①The depocenter dominated by tectonic activity controls the distribution of source rocks in the member 3 of Shahejie Group,lower segment of Dongying Group and lower segment of Minghuazhen Group,which deposited in the semideep-deep lacustrine facies environments.The subsidence and filling since neo-tectonic movement makes three sets of major source rocks be buried quickly and enter into hydrocarbon generation peak.②During a slow chasmic period to a quick depression period of Kongdian Group,a depression period of member 1 to 2 Shahejie Group,a diversion period of chasmic to a depression period of upper segment Dongying Group,and a thermal subsidence period after the second chasmic period of Guantao Group and lower segment of Minghuazhen Group,the reservoir sand bodies with different sedimentary faces were formed.The thick mudstone deposited during the thermal subsidence period after the second chasmic period is composed of a good cap.③Both anticlines formed by compression-torsion and drag structures done by tension-torsion are favorable of the formation of structure trap;the lenticular sands in the mudstone become a lithologic trap due to inter-fingering interlace between mudstones and channel sands.④There is a good match between hydrocarbon generation-expulsion period and Neogene fault activity,causing the improvement of effective migration and certain loss of petroleum.So the formation of good petroleum reservoir is required for the beneficial source-controlling conditions.⑤Faults with EW strike formed at late tectonic movement cut the early faults with NE strike and form the fault network,which links up the unconformities and make source beds connect with reservoir.the periodically active faults become the migration pathway of petroleum at active phase and act as sealing at passive phase.⑥There are two patterns of petroleum filling,one is that the petroleum migrates vertically through major faults which cut through source beds or "transfer station";the other is that petroleum migrates step by step along secondary faults and sands.