塔里木盆地BK井区砂岩储层物性分布及孔隙结构特征研究

Study on influential factors in pore structure characteristics and physical properties of BK oilfield,Tarim basin

通过铸体薄片、物性分析、常规压汞等实验方法,开展了塔里木盆地BK井区致密砂岩储层物性特征研究及储层微观孔隙结构评价,并分析了微观孔隙结构影响因素。结果表明:研究区岩性主要为中-细粒岩屑长石砂岩,变质岩屑为主要岩屑类型;平均孔隙度为6.47%,平均渗透率为0.69×10^(-3)μm^2,储层属于特低孔-超低渗透致密砂岩储层,孔渗相关性整体较好;基于毛管压力曲线参数及形态可将研究区储层孔隙结构类型分为四类,Ⅰ类至Ⅳ类孔隙结构依次变差,孔喉半径与物性参数、压力参数及均值参数均有良好的相关关系,表明孔渗、进汞压力及孔喉分选特征是影响研究区致密砂岩储层的重要参数。

By analyzing the casting sheet, physical analysis, conventional mercury and other experimental methods, the physical characteristics and micropore structure of dense sandstone reservoirs in BK well area of Tarim basin were studied,and the influence factors of micropore structure were analyzed.The results show that the lithology of the study area is mainly medium-fine grained lithic feldspar sandstone,and the main types of cuttings are metamorphic debris.The average porosity is 6.47 %,and the mean permeability is 0.69 ×10-3μm2,and the reservoir belongs to the low-permeability tight sandstone reservoir with low permeability,and the permeability correlation is better.Based on the parameters and shape of capillary pressure curve,the pore structure types of the reservoir are divided into four types,and the pore structures of class Ⅰ to Ⅳ are deteriorated in turn.And the pore throat radius has good correlation with physical parameters,pressure parameters and mean parameters,indicating that pore permeability,mercury intrusion and pore throat sorting are important parameters that affect the tight sandstone reservoir in the study area.