渤中地区火山岩特征及其与断裂关系

Features of Volcanic Rock in Central Bohai Area and its Relationship with Fracture

为了更好地预测渤中地区火山岩分布,寻找有利火山岩储层,在钻井资料分析基础上,采用三维地震资料进行火山岩相地质和地震特征研究,建立火山岩分布与断裂关系模式。渤中地区火山岩为中基性火山岩,以安山岩最为发育、凝灰岩次之;岩相以喷溢相为主,爆发相次之。渤中地区"H"型断裂控制了火山岩分布方式及分布范围,火山岩沿着断裂成"串珠状"分布。断裂的规模和火山喷发模式控制了火山岩的规模。中生界火山岩与断裂有不同赋存关系,火山岩沿基底或走滑断裂面呈裂隙—中心式喷发,火山机构串珠状叠置或在潜山内幕断层的上升盘呈中心式喷发,前者发育规模大于后者。靠近喷发中心,即靠近断裂带,物性较好的爆发相及喷溢相发育,将是火山岩油气藏勘探的有利区域。

In order to better predict the distribution of volcanic rocks in the Bohai Sea area and find favorable volcanic reservoir,on the basis of drilling data analysis,3D seismic data were used for the research on geological and seismic characteristics of volcanic facies. Relationship between volcanic rock distribution and fracture mode was established. Volcanic rock in the Bohai area is dominated by neutral- base volcanic rocks,with andesite as the most developed type,followed by Tuff. Rock facies is dominated by effusion and followed by eruption facies. In the central Bohai area,'H' type faults controlled the distribution pattern and range of volcanic rocks; volcanic rocks were distributed as ' beaded' distribution along the fractures. Scale of fractures and eruption mode of volcano controlled the scale of volcanic rocks. Mesozoic volcanic rocks had different occurrence relationship with the fault; volcanic rocks were featured by fracture- center eruption along the base or center of strike- slip fracture surface; volcanic edifice was superimposed as beaded shape or upper throw of inner faults in buried hill was featured by central eruption; the scale of the former was greater than the latter.Near the center of eruption,i. e. near the fault belt,eruption facies and effusion facies with good properties developed,which would be the favorable area for the exploration of oil / gas reservoir in volcanic rocks.