渤中21-2潜山内幕地层的地震识别与划分

Seismic identification and classification of formations in BZ21-2 buried-hill.

(中海石油(中国)有限公司天津分公司渤海油田勘探开发研究院,天津300452)

He Dianbo,Exploration and Development Research Institute,Bohai Oilfield Tianjin Branch,CNOOC Ltd.Tanggu 300452,China

渤中21-2潜山存在多套地层,岩性复杂。目前渤中21-2潜山没有钻井,无法对这些地层进行标定。基于对研究区邻区已钻探潜山的元古界花岗岩、下古生界碳酸盐岩和中生界火山岩在地震剖面上的波组反射特征的分析,根据不同地层具有不同的反射特征这一规律,应用地震相及地震波组反射特征对比和类比等方法,识别出渤中21-2潜山3套地层在剖面上的分布特征;分析了邻区已钻探潜山的地质特征,结合区域地质沉积规律,应用地震分析方法重点对下古生界碳酸盐岩的有利储集层和致密层进行了划分,刻画出下古生界碳酸盐岩上组合、致密层和下组合3套地层,获得了有利储集层的平面和剖面展布特征,为合理部署井位提供了依据。

There are several stratums with complex lithology existing in the BZ21-2 buried-hill,including Proterozoic granites,lower Paleozoic carbonate and Mesozoic volcanic rock.We cannot carlibrate the stratums because of no drilling data in the buried-hill.Based on the analysis of reflection characteristics of seismic wave group at drilled layers in the neighboring area,in terms of the different reflection characteristics of different layers,the distribution characteristics of the three strata in BZ21-2 buried-hill were identified by applying comparison and analogy of seismic facies and reflection features of wave groups.Meanwhile,the geologic characteristics of drilled buried-hill were analyzed.Combined with regional geologic sedimentary laws,the favorable reservoirs and tight layers of lower Paleozoic carbonate were classified by using seismic analysis methods,and three sets of stratums were identified,including upside group,tight layer and downside group.In addition,the distribution characteristics of favorable reservoirs on plane and profile were obtained,which provided basis for reasonable well deployment.