塔里木盆地塔河地区泥盆系东河塘组储层特征及其含油气性

THE RESERVOIR CHARACTERISTICS AND ITS PETROLIFEROUS SIGNFICANCE IN THE DEVONIAN DONGHETANG FORMATION,TAHE AREA,THE TARIM BASIN

塔里木盆地塔河地区泥盆系东河塘组砂体总体上呈近南北向展布,北西厚南东薄。储层的岩石类型以石英砂岩为主,次为岩屑石英砂岩和少量的长石岩屑砂岩。储集空间以原生粒间孔隙、粒间溶蚀孔隙、粒内溶蚀孔隙等次生孔隙为主,其他类型孔隙较少。该区东河砂岩储层经历了比较普遍的成岩作用,主要发育压实作用、胶结作用和溶蚀作用等成岩作用类型。受成岩作用影响和沉积作用控制,储层砂岩为中低孔、中低渗储层,平均孔隙度为11.25%,平均渗透率23.99×10-3μm2,孔渗正相关性好。根据储层物性及评价标准,该区储层可划分为3类,并对其进行了分类评价。通过研究认为,储层的沉积环境、岩性及物性对其含油气性具有控制作用。

The sandbodies of the Devonian Donghetang Formation were trended in direction of S--N in Tahe area, the Tarim Basin, with thick in the northwest and thin in the southeast. The reservoir rocks consisted of quartz sandstone, feldspathic litharenite and subarkose. The pore types of the reservoirs were mainly residual in- tergranular pore, intergranular dissolved pore and intragranular dissolved pore. The diagenesis of the Donghe sandstones in the area could be divided into the compaction, clay cementation, quartz overgrowth, carbonate cementation and solution. The sandstones were of middle-low porosity with a mean of 11.25% and of middle-low permeability with a mean of 23.99× 10^-3μm2 because of their sedimentation and diagenesis. According to the physical property and the criterion of evaluation of reservoirs, the reservoirs are sorted into three types and eva- luated respectively. It was indicated that the hydrocarbon-bearing capability of the reservoirs were controlled by sedimentary environment, lithologies and physical properties.