CAJ | 학술논문

以鄂尔多斯盆地北部苏里格气田的苏76、苏77区块下石盒子组盒8段为研究对象，运用岩相分析方法探讨二叠系下石盒子组盒8下段沉积演化过程中的岩相类型、叠置关系及其反映的沉积相特征。通过对研究区内38口探井取芯段岩芯的详细观察和描述，首次识别出了由洪水泥石流沉积所形成的岩相和由牵引流沉积所形成的岩相。牵引流沉积所形成的岩相主要包括颗粒支撑的正砾岩相、牵引流成因含砾粗砂岩相、牵引流成因砂岩相和牵引流成因粉砂质泥岩相；洪水泥石流沉积所形成的岩相包括杂基支撑的副砾岩、洪泛成因含砾粗砂岩相和洪泛成因粉砂质泥岩相。这二种沉积作用所形成的岩相在垂向上叠置构成不同的岩相组合类型。这些组合类型反映了苏76、苏77区块盒8下段在洪水泥石流沉积期发育湿冲积扇沉积，在牵引流沉积期发育辫状河沉积。其中，辫状河道中发育砾石质心滩、砾砂质心滩、砂质心滩，为形成有利储集砂体提供了条件。
이악이다사분지북부소리격기전적소76、소77구괴하석합자조합8단위연구대상，운용암상분석방법탐토이첩계하석합자조합8하단침적연화과정중적암상류형、첩치관계급기반영적침적상특정。통과대연구구내38구탐정취심단암심적상세관찰화묘술，수차식별출료유홍수니석류침적소형성적암상화유견인류침적소형성적암상。견인류침적소형성적암상주요포괄과립지탱적정력암상、견인류성인함력조사암상、견인류성인사암상화견인류성인분사질니암상；홍수니석류침적소형성적암상포괄잡기지탱적부력암、홍범성인함력조사암상화홍범성인분사질니암상。저이충침적작용소형성적암상재수향상첩치구성불동적암상조합류형。저사조합류형반영료소76、소77구괴합8하단재홍수니석류침적기발육습충적선침적，재견인류침적기발육변상하침적。기중，변상하도중발육력석질심탄、력사질심탄、사질심탄，위형성유리저집사체제공료조건。
He-8 section of the Lower Shihezi Formation of Permian in Su76 and Su77 blocks of Sulige gas field, the northern Ordos Basin was taken as an example;lithofacies type and superimposed relation during the sedimentary evolution of the lower section of He-8 in the Lower Shihezi Formation of Permian were discussed by the means of petrographic analysis,and the characteristics of sedimentary facies were analyzed.According to the detail observation and description of rock cores from 38 exploration wells in the study area,two types of sedimentary lithofacies formed by flooding debris flow and traction current were identified.The lithofacies formed by traction current includes orthoconglomerate lithofacies supported by grain,coarse sandstone lithofacies with gravel, sandstone lithofacies and mudstone lithofacies with silty because of traction current; the lithofacies formed by flooding debris flow includes paraconglomerate lithofacies supported by matrix,coarse sandstone lithofacies with gravel and mudstone lithofacies with silty because of flooding.Different combination types of lithofacies are vertically superimposed because of the lithofacies formed by the two types of sedimentation.The combination types reflect that wet alluvial fan develops during the deposition period of flooding debris flow,and braided river develops during the deposition period of traction current in the lower section of He-8,Su76 and Su77 blocks.Gravelly diara,gravelly sandy diara and sandy diara develop in braided channel,and it is favorable to forming reservoir sand bodies.