盆地内部火山机构的地质模式建立方法及其应用——以松辽盆地南部地区营城组火山岩为例

Establishment of Geological Modes of Volcanic Structures Within Basins and Its Application:A Case Study on the Volcanic Rocks of Yingcheng Formation in Southern Songliao Basin

在盆地地质背景基础上,根据火山机构的宏观和微观特征,综合运用地质-地球物理等手段,在松辽盆地南部地区建立营城组火山机构地质模式,讨论不同类型火山机构的储层特征。火山机构识别综合利用3类方法:包含地质界面特征、岩性岩相特征、化学成分、喷发方式和单元叠置关系的地质识别,包含自然伽马测井、电阻率测井的测井识别以及包含地震相特征、地震反射特征、地震属性的地震识别。依据以上方法将德惠断陷营城组火山机构分成3类6种,包括流纹质熔岩机构、英安质熔岩机构、安山质熔岩机构、流纹质碎屑岩机构,安山质碎屑岩机构和复合火山机构。针对长岭断陷流纹质不同类型火山机构储层的孔隙度及储集空间类型进行统计,结果表明:复合火山机构的储层物性较好,碎屑岩火山机构的储层物性次之,熔岩火山机构的储层物性较差;酸性火山熔岩机构顶部物性最好,中部物性次之,底部物性最差;火山碎屑熔岩机构在横向上分布较为广泛,在纵向上由多个堆积单元组成。

Based on the geological background of the basin and the macroscopic and microscopic characteristics of the volcanic edifices, the geological modes of the Yingcheng Formation volcanic edifices in the southern part of Songliao Basin are established by means of geology and geophysics, and the reservoir characteristics of different types of volcanic edifices are discussed. The volcanic edifices were recognized using three methods：the geological method, according to geological interface characteristics, lithological and lithofacies characteristics, chemical composition,eruption mode and unit superposition relationship;the logging method, according to natural gamma logging and resistivity logging data;the seismic method, according to seismic facies characteristics, seismic reflection characteristics and seismic attributes. Based on the recognition methods, the Yingcheng Formation volcanic edifices in Dehui fault depression are classified into 3 kinds and 6 types （ rhyolitic lava, dacitic lava, andesitic lava, rhyolitic clastic rock edifices ; and esitic clastic rockedifice ; composite volcanic edifice ）. Statistical results of porosity and reservoir space types of different types of rhyolitic volcanic reservoirs in Changling fault depression show that：the reservoir physical properly of the composite volcanic edifices is the best, that of the rhyolitic clastic volcanic edifices is secondary, and that of the lava volcanic edifices is the worst. For the acid volcanic lava edifices, the reservoir properly at the top is better than that at the middle and bottom. The volcanic clastic lava edifices are widely distributed in the transverse direction, and are vertically composed of many stacking units.