From sedimentology symbol such as rock assembled , sediment gradus , sandstone grading analysis , protogene sedimentary structure , ichnofossile and logging facies etc and palaeoenvironment background , it is confirmed that shen84 - an12block s34 segment is braid river delta system , not fan delta system ( abrupt slope ) . then it can be more partition as braid river delta plain sedimentary assembled , delta front sedimentary assembled and prodelta sedimentary assembled on core and log assembled . and delta plain sedimentary assembled can be identified four microfacies : braided distributary channel , crevasse splay , overbank deposits and interdistributary bay 沉积微相研究是储层非均质性研究的基础，研究区有丰富的岩芯资料和测井资料，通过岩石组合、沉积韵律，砂岩粒度分析、沉积构造、古生物遗迹和测井相等沉积学标志，结合古环境背景，确定沈84 ?安12块s _ 3 ~ 4段为辫状河三角洲体系，而不是前人所认为的扇三角洲(陡坡型)体系，在岩芯和测井组合上可进一步划分为辫状河三角洲平原沉积组合、三角洲前缘沉积组合和前三角洲沉积组合，其中三角洲平原沉积组合又可识别出辫状分流河道、决口扇、分流河道边部和分流间湾四种微相类型；三角洲前缘沉积组合识别出水下分流河道、水下分流河道边部和分流河口坝三种微相。
The result is that this gas pool has simple structure , only forms a little nose - like structure at the district of fenghuangshan ; this pool belongs to delta front sub - facies sedimentary model , the underwater distributary channel and mouth bar is the better sedimentary microfacies ; the physical property of the reservoir is poor , the type of pore of the reservoir rock mostly are intergranular pore , intergranular solution hole and little are intercrystalline micropore ; the influential factors of pore structure and physical property are lithofacies , lithologic character and diagenesis ; the off - take potentia of all the testing well are deadly shortness , the wells have the worth of industrial recovery only under the condition of going through sand fracturing , and in the early of binging into production , the oil and sheath pressure drop rapidly , the production of the well drop rapidly 研究认为该气藏构造简单，只在凤凰山形成了一个小型的鼻状构造；属于三角洲前缘亚相沉积模式，水下分流河道和河口坝是有利的沉积微相；储层物性差，储层岩石的孔隙类型主要有粒间孔、粒间(内)溶孔及少量晶间微孔；影响蓬莱镇组气藏储层孔隙结构及储集性的因素有岩相、岩性条件及成岩作用；所有测试井自然产能都极低，必须经加砂压裂后才有工业开采价值，且投产初期，油套压下降较快，气井产量下降迅速。
Research section braided distributary channel sandstone is mostly positive rhythm , and high porosity and seepage rate in its central - top section , low seepage rate kalk interbed in its bottom . underwater distributary channel sandstone is relatively homogeneous positive rhythm , high porosity and seepage rate in its bottom , its top low . distributary mouth bar sandstone is complex rhythm , many interbeds inside 研究区宏观非均质性特点为：研究区辫状分流河道砂体以正韵律为主，高孔、渗带在砂体中上部，底部常存在低渗透率钙质夹层；水下分流河道砂体为较均质的正韵律，下部孔渗高，上部孔渗变小，分流河口坝砂体为复合韵律，砂体内部夹层多。
