注水开发对胜坨油田坨30断块沙二段储层性质的影响

通过岩芯观测、岩石薄片、铸体薄片、扫描电镜以及压汞资料分析，对坨30断块的储层微观特征和注水开发不同时期储层的岩性、物性和含油性参数的变化进行了全面分析。主要储层的岩性属于长石砂岩，成分成熟度和结构成熟度低—中等；填隙物为黏土和钙质胶结物，微孔隙发育；储层孔隙结构可以划分为特高孔特高渗特粗喉型、高孔高渗粗喉型、高孔中高渗中喉型、中高孔中低渗细喉型4种类型；注水开发一定程度上改善了孔隙结构，使储层的最大孔喉半径增大，孔喉分布集中，孔隙度、渗透率增大，泥质含量减小，粒度中值增大, 其中泥质含量(体积分数)与孔隙度反向线性相关，渗透率与粒度中值呈现正相关。

The Influence of Water-Flooding Development on Reservoir Properties of the No.2 Member of Shahejie Formation of Tuo 30 Fault Block in Shengtuo Oilfield

On the basis of drill-core samples observation and study on rock thin section, cast section, SEM and mercury penetration curves, the microcosmic characteristics of reservoir and the parameter changes on lithology, physical properties and oiliness in different water-flooding development periods of Tuo 30 fault block are systematically analyzed. The main rock type of the reservoir is feldspar sandstone and its component maturity and structure maturity are low to middle. Cements are clay and carbonate. Tiny throats are developed. Four kinds of pore structures are distinguished,including super-high pore, super-high seepage and super-coarse throat type,high pore, high seepage and coarse throat type, high pore, middle to high seepage and middle coarse throat type and middle to high pore, middle to low seepage and thin coarse throat type. The study shows that water-flooding development improved the microstructure to some extent. It widens the biggest pore throat radius and concentrates its distribution, increases porosity and seepage rate, reduces the clay content and accordingly enlarges the median grain diameter. The relationship between clay contents and porosity rates is negative linear correlation, while the one between seepage rates and median grain diameters is positive correlation.