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
WANG Meina 1) LI Jihong 2) GUO Zhaojie 1) WANG Weifeng 3) ( 1)School of Earth and Space Sciences, Peking University, Beijing, 100871; 2)Geology department, Northwest University, Xi'an, 710069; 3)Resource Department, Petroleum University (Huadong), Dongying, 257062)
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.