潍北凹陷孔三段广泛发育火山岩地层,有效储层主要发育在溢流相.综合利用岩心、测井、地震资料对火山溢流相的旋回和期次进行划分,研究表明:潍北凹陷孔三段火山岩可划分为2个喷发旋回7个期次,每期火山溢流相熔岩层垂向可划分为上部、中部和下部3个亚相,其中上部亚相气孔和杏仁构造最为发育,是火山岩最优质的储层类型;依据火山岩熔岩流规模变化可将溢流相划分为Ⅰ型熔岩层系(扩张型)和Ⅱ型熔岩层系(收缩型)2种类型,Ⅰ型熔岩层系有利储层分布在层系上部,Ⅱ型熔岩层系有利储层分布在层系下部;Ⅰ型熔岩层系在喷发早期(4~7期)发育,规模较大,Ⅱ型熔岩层系在喷发晚期(1~3期)发育,规模较小,反映了火山早期活动强烈,晚期逐步减弱的发育过程.%The volcanic strata were widely developed in the 3rd member of Kongdian Formation of Weibei Sag,where the effec-tive reservoirs were mainly developed in effusive phases. Eruption cycles and stages of the effusive phases were categorized comprehensively using cores,logging and seismic data. The results show that volcanic rocks can be divided into two eruptive cycles and seven eruptive stages. Each eruptive cycle can be vertically divided into three subfacies: the upper subface, the central subfaces and the lower subface,respectively. Air holes and almond constructions were developed in the upper subface, which is the best reservoir type of volcanic rocks. According to the scale of lava flows, effusive phases are divided into two types,progradational and retrogradational cycles. Favorable reservoirs are mainly distributed in the upper part of the prograda-tional layers,and the lower part of the retrogradational layers. Progradational layers have larger scales, developed during the early eruption(from 4th to 7th) stages;while retrogradational layers have smaller scales,developed during later eruption(from 1st to 3rd) stages. It is suggested that early volcanic activities were intensive,which were gradually weakened through time.
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