松辽盆地营城组火山机构相带地震-地质解译

将火山机构按距火山口远近划分为火山口-近火山口、近源和远源三个相带.营城组火山机构相带有6种地震相类型,分别是丘状、透镜状、穹状、池塘状、楔状和席状地震相.丘状、透镜状和穹状均见于火山机构中心相带,但所代表的优势岩相不同,分别与爆发相、喷溢相和侵出相对应.池塘状和楔状均为近源相带,但前者以喷溢相辫状熔岩流为主,而后者代表爆发相火山碎屑岩与喷溢相熔岩互层.席状地震相是以火山沉积相为特征的远源相带为主.火山机构中心相带岩性和岩相多变、地震相复杂,这是初始喷发条件、同生垮塌、后期断裂以及孔隙和流体综合作用的结果;该带是火山岩储层发育最有利的部位.

Seismic volcanostratigraphy of Yingcheng formation in the Songliao basin, Cretaceous, NE China

Volcanic edifices in the Songliao Basin were subdivided into central, proximal and distal facies according to their architectures and facies associations. Six kinds of seismic volcanic facies units are identified in the volcanic edifice of the Yingcheng Formation. They are named after their outlooks and called mound-, lens-, dome-, pond-, wedge- and sheet-shaped seismic facies, respectively. The former three are the central facies associations and composed predominantly of explosive, effusive and extrusive facies, respectively. Pond- and wedge-shaped ones belong to the proximal facies associations and composed predominantly of effusive braided lava flow and interbedded explosive pyroclastics and effusive lavas. The sheeted one is mainly of distal facies characterized by volcanic sedimentary facies. Lithology and lithofacies change rapidly in the center of volcanic edifice and their seismic responses are complex. The key controlling factors for that include eruptive conditions, contemporaneous collapse, post-volcanism faulting, porosity and fluid. The central parts of the volcanoes are the most favorable for creating volcanic reservoirs.