定边唐山地区长2、长6段砂岩储层的孔隙类型与孔隙结构特征研究

Pore Types and Texture of Sandstone Reservoir of Chang 2 and Chang 6 Reservoirs in Tangshan Region of Dingbian Oilfield

在铸体薄片鉴定、粒度分析及物性分析统计的基础上,对定边唐山地区长2、长6段砂岩储层的孔隙类型、孔隙结构等微观特征进行了深入分析,结果表明:长2、长6段储集空间主要为粒间溶孔、原生残余粒间孔、岩屑粒内溶孔、杂基溶孔和高岭石晶间孔,局部发育微裂隙;渗透率随孔隙度的增大而增大,而孔隙度和渗透率的大小又与砂岩的孔隙结构有关。优质储层具粗粒结构和含砾支撑结构,这种结构有利于孔隙水的流动,促进填隙物溶蚀和粒间溶孔的形成。指出粗粒结构与含砾支撑结构的石英砂岩储层物性较好;含砾支撑结构储层具有双众数粒度分布特征,有利于孔隙水的流动,促进填隙物溶蚀和粒间溶孔的形成,使得储层的渗透率得到提高。

Based on casting thin section identification, grain size analysis and physical property analysis, pore types and texture of sandstone reservoir of Chang 2 and Chang 6 reservoirs in Tangshan region of Dingbian oilfield were analyzed. The results show that, the reservoir space of Chang 2 and Chang 6 reservoirs is mainly intergranular dissolved pore, native residual intergranular pore and dissolved pore in cuttings, mixed solution pores, and kaolinite intercrystal pore, locally developed microcracks; the permeability increases with the increase of porosity; and the porosity and permeability are related to the pore structure of sandstone. High quality reservoirs have coarse grain structure and conglomeratic support structure; these structures are conducive to the flow of pore water, promoting filler material corrosion and the formation of intergranular dissolved pore. It＇s pointed out that the quartz sandstone reservoir with coarse grain structure and conglomeratic support structure has good property; the reservoir with conglomeratic support structure has the double modal particle size distribution, is conducive to the flow of pore water, promoting filler material corrosion and the formation of the intergranular dissolved pore, so the reservoir permeability can be improved.