黔东九门冲组灰岩重结晶作用与储集性

THE RECRYSTALLIZATION AND RESERVOIR PROPERTIES OF THE JIUMENCHONG LIMESTONE,FORMATION,EASTERN GUIZHOU

黔东下寒武统九门冲组灰岩是由灰泥沉积物经重结晶作用而成的晶粒结构灰岩。由于不同地区、层段的沉积、成岩和构造作用的差异,导致了灰岩重结晶演化途径、阶段上的不同。一般可见两大演化途径和2～3个演化阶段。沉积特征主要决定了演化途径,并对第一演化阶段发生显著的影响;压实、压溶作用和有机质演化对第二阶段影响最甚,并决定着次一级演化分枝;构造应力对第三阶段演化起决定性作用。与上述演化相对应的储集性也县有两大演化途径和2～3个演化阶段及三种可能储集类型,最大可能是缝隙型,最佳储集类型是孔隙-缝隙型。东部大断裂带附近,如镇远、施洞口、南皋一带多为缝隙型,西部下段亦为缝隙型,而中段在曲率低值区或无断裂一带是孔隙型或致密的非储集岩。

The Jiumenchong limestones formation,Lower Cambrian,eastern Guizhou is Characterized by its crystalline-granular texture,showing that lime mud sediment has been recrystallized.Because sedimentation,diagenesis and str- ucture action of the limestone are different in different area and layer,it is different in their path and stage of the limestone reerystallization evolu- tion. Usually,it is obvious that there are two main evolutional paths and 2-3 evolutional period.The evolutional path is mainly decided by sedimentary features.The sedimentary features have a predominant influence in the first evolutional period.Compaction,pressolution and maturation of organic com- ponents have major influences in second evolutional period,and they are decisive factors in the secondary evolution.Structural stress has a decisive function in the third cvolutional period.Correspondingly,two main evolu- tional paths,two-three evolutional periods and three possible reservoir rocks types are abserved,with the fissure types as the most possible case,and the prosity-fissure type is the best reservoir rocks.For example,Zhenyuan, Shidongkou,Nangao,near to the eastern large fault nearly all reservoir rocks are of the fissure type.There is fissure type reservoir formation in the lower part in western part too.There is fissure type or nonreservoir rock near the area with lower curvature or unfaulted area in the middle part.