准噶尔盆地西北缘火山岩储层的综合地球物理预测

Integrated geophysical prediction of volcanic reservoir in Northwestern margin area of Junggar Basin

(中国石油勘探开发研究院西北分院,甘肃兰州730020)

Northwest Branch,Research Institute of Petroleum Exploration and Development,CNPC,Lanzhou 730020,China

19世纪末至20世纪初,国内外发现了很多火山岩油气藏,储层岩性为玄武岩、安山岩和流纹岩等,储集空间以裂缝为主。而准噶尔盆地西北缘夏72井区块二叠系风城组火山岩油气藏储层岩性为熔结角砾凝灰岩,储集空间以气孔为主。钻探证明,该类火山岩储层横向非均质性强,研究和预测优质储层分布范围难度都较大。对准噶尔盆地西北缘夏72井二叠系风城组火山岩油气藏的主控因素进行了分析,提出了裂隙式火山岩喷发模式,其储层分布主要受控于火山口及古地貌特征。根据这一地质认识,利用分频相干技术,古地貌恢复技术,正、反演技术,三维雕刻技术和多属性融合技术等多种地球物理技术,对火山岩优质储层在平面上的展布特征进行了精细刻画。并利用此研究成果部署钻探了风南4井,获得了工业油气流。同时指出下一步的勘探方向是沿夏红南断裂带的近火山口相。

From the end of 19th century to the beginning of 20th century,a lot of volcanic reservoirs have been explored home and aboard.The lithology of the reservoirs is basalt,andesite,rhyolite and so on,and the hydrocarbon bearing space is mainly of fractures.However,the lithology of volcanic reservoir of Permian Fengcheng Formation at Xia72 well area in Northwestern Margin of Junggar Basin is lava tuff breccias,and its storage space is mainly of air hole.The drilling data proves that this kind of volcanic reservoir has strong lateral heterogeneity.As a consequence,the investigation and prediction of its distribution scale is complicated.So we analyzed the main controlling factors of volcanic reservoir of Permian Fengcheng Formation at Xia72 well area,proposed the mode of fractured volcanic eruption,and identified that its reservoir distribution is controlled by the characteristics of crater and paleo-geomorphology.In terms of the geologic recognition,many geophysical techniques were used to fine predict the plane distribution of high-quality volcanic reservoir,including frequency-division coherent technique,paleo-geomorphology restoration technique,forward modeling and inversion technique,3D sculpture technique as well as multiattributes fusion technique.The research results are used to deploy and drill well Fengnan4 that obtained industrial gas flow,and pointed out that the future exploration target is near to crater along Xiahongnan faulted belt.