鄂尔多斯盆地下寺湾油田三叠系长7段致密砂岩储层特征及控制因素

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中图分类号：P618.13 文献标识码：A 文章编号：2097-5465（2025）06-0046-13

Abstract;Basedonxperimentalaalysessuchastinsctionidenticationsaningelectronmicroscopy（SEM），ige mercuryinjectionandX-raydifraction，asystematicstudyonthecharacteristicsandcontrollingfactorsofthetightsandstone reservoirsintheChang7memberoftheTriasscintheXiasiwanOifieldoftheOrdosBasinwascarredout.Theresultshowthat thereservoir rock typesare mainly lithic arkose and arkose，accounting for 49.67 % and 36.04% respectively.Overall，theyare ultra-lowporosityandultra-lowpermeabiltyightreservoirs.Theporetypesaremainlyfeldspardisoledporesandintergranular pores，accounting for1.95% and 4. 53% respectively，and lithic dissolved pores and microcracks are occasionally seen.The strength ofsedimentaryhydrodynamicconditionscontrolsthephysicalpropertiesofthereservoirs，hichismanifestedasthecoaserthe particlesizeandtetertesortig，tehetecalpropetis.agenetictrsfoationsiicantlyctstseoi storageperformance.Compactionandcarbonatecementationleadtoalargelossof primarypores，andclaymineralcementation furtherdamagesthephysicalpropertiesofthereservos.Thedisoledporesformedbydisolutionimprovethehyicalpropertis of the reservoirs.Quantitative analysis of porosity indicates thatthe average initial porosityof thereservoirs is 39.7% . The average porosity reduction rate caused by compaction reaches 55. 76% ；theaverageporosityreductionrate causedbycementationreaches 20.85% ；and the average porosity increase rate caused by dissolution reaches 5.32% ，which effctively improves the physical properties of the reservoirs.

Keywords;Xiasiwan oilfield；Chang7member；reservoir characteristics；pore evolution；controling factors

0引言

致密砂岩是陆相湖盆中常见储集体类型之一，其宏观分布主要受沉积相带控制，储集物性整体较差，孔隙度小于 10.0% ，渗透率多低于 1.00mD[1] 。（剩余14482字）