黄河口凹陷东南缘火山活动特征及其对油气成藏条件的影响

Volcanic activity and its effect on the hydrocarbon accumulation conditions in the southeastern margin of Huanghekou sag

为解决黄河口凹陷东南缘钻井稀少、火山岩发育及油气分布不清等问题,利用三维地震、钻井和地化分析等资料,结合沉积背景,分析该区沙二段—东一段火山岩分布、火山活动特征及其对油气成藏条件的影响。结果表明:黄河口凹陷东南缘沙二段—东一段主要发育2种火山相类型:火山通道相和溢流相。火山通道相往往成群出现,溢流相以多期叠加为主,局部发育孤立的火山通道相和溢流相。纵向上,沙二段—东一段火山活动呈"强—弱—强"的演化特点;平面上,不同时期、不同位置火山岩的分布和活动强度具有明显的差异性。火山岩的分布阻碍烃源岩的演化进程,火山活动形成的火山通道相和溢流相占据沉积可容空间,对烃源岩和储层的分布起阻碍作用;与火山岩密切相关的沸石的形成对储层物性具有明显的改善作用。火山岩发育形成局部盖层,使油气更有利于在盖层下的古近系储层富集。该结论对寻找火山岩发育区有利勘探目标提供一定的帮助。

Aiming at the drilling scarce,fuzzy volcanic rocks and distribution of oil and gas issues,usingof three-dimensional seismic,drilling,analysis data,combined with the background deposition,we quantitatively studied the volcanic activity periods and distribution of volcanic rock of Es2-Ed1 in the southeastern margin of Huanghekou sag,and the effects of volcanic activity on hydrocarbon accumulation conditions.The results showed that there major developed two kinds of volcanic facies:Volcanic channel and overflow equal,mainly in the volcanic channel group and multi-stage superimposed overflow facies,local developed isolated volcanic channel and overflow phase.Longitudinally,the volcanic activity was 'strong-weak-strong' in Es2-Ed1.On the plane,the distribution of volcanic and intensity of activity have obvious differences at different locations in different times.The distribution of volcanic hindered the evolution of the process of source rocks,and the volcanic channel and volcanic overflow phase occupied the accommodation space,and hindered the distribution of source rocks and reservoirs.But it has a protective effect on the lower portion of the reservoir;and the dense cracks and zeolite which were closely related to volcanic had significant improvement on reservoir properties.The distribution of volcanic rocks on the plane can be formed local seals,and the induced fractures and faults related to volcanic eruption in Paleogene had favorable for hydrocarbon migration,and accumulation of hydrocarbon in Paleogene.The law provided reference for finding favorable exploration targets in volcanic rocks area.