海拉尔盆地兴安岭群火山岩岩石组合类型及层位卡取方法

Volcanic lithology and horizon determining method for Xing'anling Group in Hailar Basin

海拉尔盆地于见尔湖坳陷贝尔凹陷、乌尔逊凹陷及扎赉诺尔坳陷巴彦呼舒凹陷发育侏罗系兴安岭群地层.岩性复杂.火山岩分布广泛是其主要特征,准确卡取兴安岭群地层可以保证井资料质量.降低钻井成本。通过对兴安岭群多年来现场录井的实物资料分析、归纳认为.海拉尔盆地兴安岭群火山岩岩石为火山熔岩类、正常火山碎屑岩向熔岩过渡岩类、正常火山碎屑岩类和正常火山碎屑岩向沉积岩过渡岩类4种娄型。兴安岭群岩石组合为中基性火山熔岩+火山碎屑岩向沉积岩过渡岩石组合等3种类型。兴安岭群测井双侧向视电阻率曲线为厚层状、山峰状、不规则齿状高电阻率值.一般都高于50Ω·m,自然电位曲线较平直.自然伽马曲线呈高值特征。在海拉尔盆地录井现场应啊岩性变化及测蚌曲线变化特征卡取了22口井的兴安岭群地层.经完钻后验证.实际地质分层吻台。实践证明利用录井岩石及其组合特征.结合删井曲线变化特征可以准确卡取兴安岭群地层.为甲方决策提供依据.也为资料后续应用及研究提供指导。

Hailar Basin developed Jurassic Xing anling Group strata at Beier sag of Beier Lake depression,Wuerxun sag and Bayanhushu sag of Zalailuor depression.Its main features are lithology is complex,volcanic rock distributes widely.Accurately determining Xing anling Group strata can ensure data quality and reduce drilling cost.Through years of analysis on real data of field mud logging for Xing anling Group,the author summed up that volcanic rock of Xing anling Group in Hailar Basin is 4 types of volcanic lava,the transit of pyroclastic rocks to lava,normal pyroclastic rocks and the transit of normal pyroclastic rocks to sedimentary rocks.In Xing anling Group,the rock associations are intermediate-basic volcanic lava + the transit of pyroclastic rocks to sedimentary rocks and the other two types.For Xing anling Group,apparent resistivity curves of dual laterolog are high resistance in shapes of thick bed,mountain peak and irregular dentate,which are generally higher than 50 Ω·m,self-potential curve is straight,gamma ray curve shows a high value feature.In Hailar Basin,mud logging successfully determined the horizon of Xing anling Group for 22 wells by applying the change characteristics of lithology and logs.The drilled wells verified they coincided with actual geological stratification.Practice has proved that the horizon of Xing anling Group can be accurately determined by using rocks and rock combination of mud logging,and change characteristics of logs,thus providing basis for Party A s decision and guidance for the application and research of the data.