义东油田义东断裂带成藏规律分析

 受义东断裂带控制,四扣洼陷北部发育了多种类型油气藏,且义东断裂带南北构造差异明显,造成成藏模式也存在较大差异。研究义东断裂带成藏条件及成藏规律,对该区的进一步油气勘探具有重要的意义。根据岩心、录井、钻井、地震等资料,对四扣洼陷义东断裂带成藏条件及成藏规律进行综合研究。结果表明,与义东断裂带相邻的四扣洼陷沙三、四段具有丰富的烃源岩条件、良好的储盖组合及封闭性,成藏条件十分优越。义东断裂带发育有多个岩性及构造－岩性油气藏。油藏具有沿断裂带分布及“浊积扇”式等特征。其中沙四段油气成藏特征为南部断阶带以礁灰岩储集层形成的岩性油藏,北部为碎屑岩储集层形成的构造－岩性油藏;沙三段发育小规模近岸水下扇、浊积扇构造－岩性油藏和浊积水道砂体岩性油藏;沙二段发育扇三角洲和砂质滩坝,常形成构造－岩性油藏。

The Reservoir Patterns of Yidong Fault Zone in Yidong Oilfield

Under the control of Yidong fault zone, many kinds of oil reservoirs are formed in the north of Sikou sag. Meanwhile, because of the significant tectonic differences exist between the north and the south structures of Yidong fault zone, the reservoir-forming patterns are quite different. Therefore, studying reservoir-forming conditions and patterns has the important significance for further hydrocarbon exploration. Based on the data of core, well logging, well drilling, and seismic analyses, the reservoir-forming conditions and patterns of Yidong fault zone are discussed. The results show that due to abundant source rocks, good reservoir-cap assemblage, and sealing property, the reservoir-forming conditions are quite superior, and many lithologic reservoirs and structural lithologic reservoirs are formed, that have the pattern feature of "turbidite fan" and distribute along the faulted zone. The feature of the fourth member of Shahejie Formation (Es₄) are that the reef limestone lithologic reservoirs are developed upon the south fault terrace, and clastic structural lithologic reservoirs are formed in the north part. In the third member of Shahejie Formation (Es₃), some small nearshore subaqueous fan, turbidite fan structural lithologic reservoirs, and turbidite channel lithologic reservoirs are developed. Nevertheless, fan delta and sandy beach bar structural lithologic reservoirs are mainly developed in the second member of Shahejie Formation (Es₂).