黄骅坳陷三马地区中—深部储层成岩作用及主控因素分析

Diagenesis of Middle-deep Clastic Reservoir Rocks and Its Controlling factors in Sanma Area, Huanghua Depression

黄骅坳陷三马地区储集岩样品的显微特征及成岩矿物的组合关系分析结果表明 ,三马地区下第三系中深层储层主要处于晚成岩A期 ,成岩现象包括石英、长石的次生加大、碳酸盐矿物胶结作用、矿物交代作用、溶解作用和粘土矿物转化作用等。其中石英次生加大于 2 70 0m左右开始出现 ,随埋深增大 ,石英增生加强 ;长石次生加大现象不十分普遍 ;碳酸盐胶结作用包括早期自生泥晶方解石胶结作用、连晶方解石和晚期白云石 (或铁方解石 )的胶结作用。在扫描电镜下可见到方解石与含铁方解石集合体充填在粒间孔隙中或与石英、钠长石及粘土矿物共生 ,白云岩多呈菱形粒状分布于粒间 ;常见的交代现象主要有方解石交代长石、石英及粘土矿物 ,粘土矿物交代长石、石英等 ;溶解作用主要有长石的溶解、碳酸盐颗粒的溶解和方解石胶结物的溶解等 ,粘土矿物的转化主要为蒙脱石、高岭石向伊利石(或绿泥石 )转化。还讨论了储层岩相、岩性特征、孔隙水中有机酸含量、早期方解石的充填。

The micro characteristics and composite relation between diagenetic minerals of reservoir rock samples from Sanma area, Huanghua Depression has been analyzed. The research result shows that the diagenesis of reservoir rock is in the later diagenetic A stage. The diageneses include quartz and feldspar overgrouth, carbonate mineral cementation, metasomasis between minerals, minerals corrosion and clay mineral translformation. Quartz overgrouth appears at depth of 2 700 m, and it is enhanced with the increasing of burial depth; The feldspar overgrouth is not common; Carbonate mineral cementation include early micrite calcite cementation, crystal stock calcite and later dolomite/ankerite/ferroan calcite cementation. With the aid of scanning electron microscope, these characteristics could be seen that the calcite or ferroan calcite filling in intergranular pore, associated with quartz, albite, clay mineral. Domomite in shape of lozenge is distributes in intergranular pore; The metasomases include calcite metasomasis of quartz, feldspar or clay mineral; clay mineral metasomasis of feldspar or quartz; the corrosion include the dissolution of feldspar, carbonate mineral or calcite; The transformation of clay mineral include that the smectite or kaolinite to illite. The primary factors controlling diagenesis of reservoir rocks, including as lithofacies, lithology, geochemical charateristics of water in pore (organic acid content), early calcite cementation, early hydrocarbon filling and abnormal high pressure of fluid in pore have also been discussed in this paper.