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以准噶尔盆地腹部莫西庄地区三工河组(J_1s)低孔渗储层为研究对象,通过系统的岩石薄片观察、扫描电镜、阴极发光及烃类荧光显微鉴定,依据成岩产物之间及其与烃类流体(油包裹体和孔隙沥青)之间的赋存关系,建立了储层成岩演化和油气充注的时间序列,恢复了关键油气充注时期的储层古物性,探讨了孔隙演化与油气成藏的匹配关系。结果表明:三工河组储层为低成分成熟度的长石岩屑砂岩和岩屑砂岩,压实作用、碳酸盐和黏土矿物胶结作用是导致储层低孔渗的主要原因,石英颗粒表面覆盖的绿泥石膜难以有效地保持原生孔隙,次生溶蚀孔隙是主要储集空间;储层成岩演化具有显著的差异性,在压实作用下富含软岩屑砂岩中软岩屑强烈塑性变形致使早期致密,而钙质强胶结砂岩因成岩早期的碳酸盐胶结发生致密化,低软岩屑—弱胶结砂岩主要经历了3期有机—无机流体作用交替,分别以无荧光炭质沥青、黄色荧光油、蓝—白色荧光油等3期烃类流体活动为划分标志;在晚白垩世末关键油气成藏时期(距今100~70Ma),高软岩屑和钙质强胶结砂岩古孔隙度低于8%,早期致密化储层难以发生油气注入;低软岩屑—弱胶结砂岩在晚白垩世末期可保持中—高孔渗性,普遍发生了早期油气充注,早期原油注入不能阻止储层深埋过程中物性变差的趋势,但可能改变局部储层的润湿性质,油湿通道网络是晚期成藏阶段(距今62~0Ma)低孔渗储层条件下发生大规模油气注入的主要原因。
Taking the low Permeable reservoir of the Sangonghe Formation (J_1s) in the Moxizhuang area, located in the abdomen of the Junggar Basin, as the research object, through the systematic observation of thin sections of rock, scanning electron microscopy, cathodoluminescence and hydrocarbon fluorescence microscopy, And the hydrocarbon fluids (oil inclusions and pore bitumen), established the time series of reservoir diagenetic evolution and hydrocarbon filling, restored the reservoir antiquities during the key oil and gas filling periods, and discussed the evolution of pores Matching relationship with hydrocarbon accumulation. The results show that the reservoirs in the Sangonghe Formation are feldspathic lithic sandstones and lithic sandstones with low component maturity. The compaction, the cementation of carbonate and clay minerals are the main reasons leading to the low porosity of the reservoir, The surface covered chlorite film is difficult to effectively maintain the primary porosity, the secondary dissolution of the pores is the main reservoir space; reservoir diagenesis evolution has significant differences in the compaction of soft rock fragments rich soft detrital strong plasticity Deformation causes early densification, whereas calcareous cemented sandstones densify due to carbonate cementation in early diagenesis. The low-soft detritus-weakly cemented sandstone underwent three organic-inorganic fluid interactions alternating with carbonless asphaltic , Yellow fluorescent oil and blue-white fluorescent oil as the distinguishing marks. During the late Cretaceous during the key hydrocarbon accumulation period (from 100 to 70 Ma), the high soft detritus and calcareous strongly cemented sandstone Porosity less than 8%, oil and gas injection is difficult to occur in the early densification reservoirs. Low soft rock cuttings and weakly cemented sandstones can maintain mid-high porosity and permeability during the late Cretaceous. Early oil and gas filling and early oil injection Can not stop However, it may change the wetting property of local reservoirs. The oil-wet channel network is a large-scale oil and gas injection under the condition of low porosity and permeability reservoir in the late stage of hydrocarbon accumulation (62 ~ 0 Ma up to now) The main reason.