柴北缘马北地区下干柴沟组储层特征

Reservoir Characteristics of Xiaganchaigou Formation in Mabei Area of Northern Qaidam Basin

运用岩心、铸体薄片、扫描电镜和化验资料等,系统研究了柴达木盆地北缘地区下干柴沟组储层孔隙结构特征,并对储层发育的控制因素进行了分析。结果表明,下干柴沟组储集空间以原生粒间孔为主,其次为溶蚀孔和少量裂缝。储层综合评价为中孔—细喉道—中渗型储层。沉积相带是储层储集性能的主要控制因素,该区发育的辫状河河床亚相的砂砾岩是主要储集岩。成岩作用对储集性能也有影响,其中压实作用和胶结作用降低孔隙度,溶蚀作用增加次生孔隙。

Based on core observation, cast thin section, scanning electron microscopy and permeability analysis,we studied reservoir pore structure characteristics of the Xiaganchaigou Formation in northern Qaidam basin and analyzed reservoir development control factors. The results show that, the original intergranular pore is the main type of reservoir space of the Xiaganchaigou Formation,followed by the dissolu.tion pores and small cracks. The reservoirs are comprehensively evaluated of medium porosity, small pore throat radius and medium penetration reservoirs. Sedimentary facies are the main control factors of reservoir performance;the conglomerate rock of braided river bed subphase in this district is the main reservoir rock. Diagenesis are also affected the reservoir performance,in which compaction and cementation decrease the porosity, dissolution increases secondary porosity.