Sandstone rock in Zhengnan slope is sector sedimentary under water which is formed in the fourth section of Shahejie formation in Paleogene period.Grade of maturity of rock structure and contents are low which are majorly double and multi-model structures.Major rock-forming functions which will effect reservoir rock are described firstly,and crack types and structure characteristics of reservori are analysed as well.This type of sandstone rock reservoir has the characteristics of multi-types and complicated...