Based on detailed observation of cores,thin section,well logging and seismic data analysis,high frequency sequence and sedimentary microfacies of the Upper T2l4 were studied in the Shiyangchang-Jinma-Yazihe area of foreland of Longmen Mountains in western Sichuan Depression.Combined with logging interpretation results,the reservoir distribution and controlling factors of reservoir development are analyzed.The results indicate that the Upper T2l4 can be divided into one fourth-order sequence,and may be further divided into multiple fifth-order and sixth-order high frequency sequences.The high frequency sequence has the characteristics of sedimentary assemblages obviously shallowing upward and their horizontal correlation is good.Sedimentary environments mainly are tidal flat in the research area,and the tidal flat deposits mainly develop intertidal zone and subtidal zone sub-facies.Lithology of flat deposits is varied in the vertical direction and is more stable in horizontal orientation.Intertidal zone is a favorite sub-facies for reservoir development,and can be divided into dolomite flat,algae dolomite flat,dolomite-lime flat micro-facies.Subtidal zone can be divided into lime flat,algae lime flat,dolomite lime flat micro-facies.Silty-fine dolomite flat,algal (laminated) dolomite flat in the intertidal zone is favorable micro-facies for reservoir development.They were usually distributed in middle-upper part of upper and lower reservoir with clear reservoir cycles.The favorable intertidal micro-facies distribution reservoir for development is controlled by (high frequency) sequence,which also has a certain impact to later diagenesis.The high frequency sequence is the key factor to affect reservoir formation and distribution.%通过薄片、岩心、测井和地震资料,对四川盆地川西坳陷中段龙门山前石羊场-金马-鸭子河地区雷口坡组四段上亚段储层高频层序、沉积微相进行研究;结合储层测井解释结果,总结储层在层序和沉积微相中的分布,分析层序沉积对储层发育的控制.结果表明,雷四上亚段构成一个完整四级层序,并可进一步划分为多个五级和六级高频层序.高频层序的向上变浅沉积旋回特征明显,横向对比好.雷四段上亚段在研究区主要为潮坪相沉积,主要发育潮间带和潮下带亚相,纵向上岩性多变,横向上分布较为稳定.潮间带是储层发育的有利亚相,可划分为云坪、藻云坪和灰云坪等微相;潮下带可划分为灰坪、藻灰坪和云灰坪等微相.潮间带粉晶云坪、藻(层叠)云坪是优质储层发育的有利微相,一般发育于上、下两个储层段高频层序中、上部,储层旋回对比性好.高频层序控制潮间带有利沉积微相分布,对后期成岩作用也具有一定的影响,是储层空间展布与储层发育的关键控制因素.
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