埕岛—桩海地区中生界火成岩油气成藏特征

Characteristics of Volcanic Reservoir Accumulation in Mesozoic Group of Chengdao-Zhuanghai Area

根据油气成藏基本要素,对埕岛—桩海地区中生界火成岩油气成藏条件进行了系统研究,并对油藏分布规律、成藏模式及有利勘探区块进行了分析。结果表明:中生界火成岩油藏为多源供烃,烃源岩为埕北、五号桩及桩东凹陷沙三段的湖相优质烃源岩;火山爆发相和溢流相的安山岩、安山质火山角砾岩储层发育较好,发育了2类有利储盖组合;以复杂断块圈闭为主,具有良好的油气运移和保存条件;油藏主要分布在西北区,具有含油层系从南向北由蒙阴组向西洼组过渡的特点;形成了裂缝-岩性、不整合-岩性和断块-岩性3种油气成藏模式,在油气藏模式发育区内的5个断块均为下步油气勘探的有利目标。

Based on reservoir forming elements,a systematic research has been carried out on reservoir forming conditions of igneous rocks in Mesozoic Group of Chengdao-Zhuanghai area. Analysis has been carried out on the reservoir distribution pattern,reservoir forming models and favorable exploration blocks. The results show that the igneous rock reservoirs of Mesozoic Group have multiple hydrocarbon sources,including superior lacustrine facies source rocks in Chengbei,Wuhaozhuang and Sha-3 member of Zhuangdong Depression; andesite and andesitic volcanic breccia reservoirs of volcanic explosion and overflow facies are well-developed,forming two types of favorable reservoir-cap combinations; there developed mainly complex faulted block traps,with good hydrocarbon migration and preservation conditions. The reservoirs are primarily located in the northwest part,where oil-bearing formations transit from Mengyin Formation to Xiwa Formation from south to north; there are 3 reservoir forming models,namely fracture-lithology,unconformity-lithology and fault-lithology,And 5 faulted blocks in the reservoir forming model area are all favorable targets for further hydrocarbon exploration.