华北地台中北部寒武系—奥陶系白云岩储层特征及主控因素

Reservoir characteristics and main controlling factors of Cambrian-Ordovician dolomite in the north central part of North China Platform

华北地台中北部寒武系—奥陶系发育白云岩,主要分布在府君山组、馒头组上部、毛庄组上部、张夏组中部、冶里组上部、亮甲山组上部、下马家沟组、上马家沟组以及峰峰组下部。通过野外露头、岩心等资料分析了白云岩储层的成因及控制因素。其岩石类型为具有原岩结构泥微晶白云岩和颗粒白云岩,以及无原岩结构的粉晶白云岩、细晶白云岩、中—粗晶白云岩等。白云岩储集空间类型有晶间孔、晶间溶孔、晶内溶孔、粒间孔、粒内溶孔、溶蚀孔洞以及少量溶蚀缝,并以晶间孔、晶间溶孔为主。寒武系—奥陶系白云岩主要形成于蒸发白云石化作用、渗透回流白云石化作用、埋藏白云石化作用、构造热液白云石化作用等过程中,有利的沉积环境、持续的白云石化作用和不同时期的溶蚀作用共同控制了研究区白云岩储层的形成。

To study the genesis and controlling factors of dolomite reservoirs,through the analysis on field outcrop,core and other data,the Cambrian-Ordovician dolomites developed in the north central part of North China Platform are mainly distributed in the Fujunshan Formation,upper part of Mantou Formation,upper part of Maozhuang Formation,middle part of Zhangxia Formation,upper part of Yeli Formation,upper part of Liangjiashan Formation,lower part of Majiagou Formation,upper part of Majiagou Formation and lower part of Fengfeng Formation.The rock types include the microcrystalline dolomite and granular dolomite with protolith structure as well as the micritic dolomite,fine dolomite and medium dolomite without protolith structure.The storage space of the Cambrian-Ordovician dolomite reservoirs include intercrystalline pore,intercrystalline dissolution pore,intracrystalline dissolution pore,intergranular pore,intragranular dissolution pore,intragranular dissolution vug and a small amount of dissolution fractures,dominated by intercrystalline pore and intercrystalline dissolution pore.The Cambrian-Ordovician dolomite is mainly formed in the process of evaporative dolomitization,permeation and dolomitization,burial dolomitization,and tectonic hydrothermal dolomitization.The favorable sedimentary environment,continuous dolomitization and the dissolution in different periods jointly control the formation of dolomite reservoir in the study area.