通过薄片、扫描电镜、阴极发光、岩心物性及测井曲线对老君庙油田古近系M层进行了储层特征与形成机理研究， 包括沉积储层基本特征、成岩作用及孔隙演化分析等。结果表明，M层为快速堆积下的沉积物，分选差，杂基含量高，总 体属于相对细粒的冲积扇相沉积；主要储集空间为粒间孔，为中孔低渗储层；成岩作用类型主要有压实、胶结和溶解作用 等。沉积作用控制了储层的原始孔隙度，杂基含量高，分选较差的储层原始物性差，主要分布在扇根片流带片流砂坝和扇 中漫流带；相比而言，低杂基含量，分选相对较好的辫流带砂岩受到碳酸盐胶结物的影响大，胶结作用进一步降低了这类 储层物性，使储层整体物性表现为低渗透。杂基含量和碳酸盐胶结是导致储层为低渗透的主要因素。

Basedonagreatdealofthinsections,cathodoluminescence,electronmicroscopic,corephysicalpropertyandloggingdata,the characteristicsofreservoirandformationmechanismoftheMalluvialfanreservoirinLaojunmiaoOilfield,wasdiscussed,includingthe sedimentarycharacteristicsofreservoir,diagenesisandporosityevolutionwereanalyzed.TheresultsshowthatMreservoirhaverapid accumulation,poorsortingandhighmatrixcontents,itoverallbelongrelativefinealluvialfan.Themainreservoirspaceareintergranular poreswiththecharacteristicsofmediumporosityandlowpermeability.Thedominantdiagenesisinthestudyareahavecompaction, cementationanddenudation.Sedimentationcontrolledtheprimarypores.Thehighmatrixcontentsandpoorsortingresultinthepoorreservoirproperties.ThekindofreservoirisprimarilydistributioninSheetflooddepositionandbraidedriver.Incontrast,thelowmatrix contentsandgoodsortingofthebraided-streambeltreservoirisgreatlyaffectedbycarbonatecement.Carbonatecementfurtherreduce thereservoirphysicalproperties,whichresultinfeaturesoflowpermeableforMreservoir.Thecontentofmatrixandcarbonatecement aremajoraffectingfactorsforlowreservoirphysicalproperty,whichcausethequalitydifferenceanddistributionofreservoir.