准噶尔盆地前哨地区有利砂体展布规律及演化模式——以下侏罗统三工河组二段一砂组为例

Distribution and evolution of favorable sand in Qianshao Area of Junggar Basin: a case study from the first sand group of the second member of the Sangonghe Formation of the Lower Jurassic

准噶尔盆地前吵地区三工河组有利砂体展布规律不明,砂体类型不清,制约油气资源的勘探开发。根据岩心观察、粒度分析、测井及地震资料,结合层序地层学原理,利用90°相位转换技术及地震多属性融合技术,建立等时地层格架,明确有利砂体类型、砂体展布规律和砂体演化模式。结果表明:研究区有利砂体以浅水三角洲内前缘水下分流河道砂体、浅水三角洲外前缘水下分流河道砂体和砂质碎屑流成因的湖底扇砂体为主;顺物源方向,2级坡折带控制的三角洲前缘砂体逐渐向3级坡折带之下的湖底扇砂体过渡;有利砂体为湖侵阶段产物,由3个退积旋回演化形成;受控于多级坡折带,初次退积旋回与二次退积旋回形成砂质碎屑流成因的湖底扇砂体,三次退积旋回形成浅水三角洲外前缘砂体和浅水三角洲内前缘砂体。该结果对前哨地区三工河组岩性油气藏的下一步勘探开发目标部署具有指导意义。

Due to the unclear distribution of favorable sand and the types of sand in Qianshao Area of Junggar Basin,the in-depth exploration and development of oil and gas resources in the J 1 s 21 is restricted.Based on core observation,grain size analysis,logging and seismic data,combined with the principle of sequence stratigraphy,using 90°phase conversion technology and seismic multi-attribute fusion technology,the favorable sand types,sand distribution regulation and evolution model are defined.The results show that the favorable sands in the study area are mainly underwater distributary channel in the inner front of shallow water delta,underwater distributary channel sand in the outer front of shallow water delta and sublacustrine fan sand caused by sandy debris flow.Along the source direction,the delta front sand controlled by the secondary slope break zone gradually transits to the sublacustrine fan sand under the third slope break zone.The favorable sand is the product of lake transgression stage,which is evolved from three retrogradation cycles.Controlled by multi-stage slope break zones,the first and second regression cycles form sublacustrine fan sand caused by sandy debris flow,and the third cycles form shallow water delta outer front sand and shallow water delta inner front sand.This study has guiding significance for the exploration and development target deployment of lithologic reservoirs in Sangonghe Formation in Qianshao Area.