Abstract: The percolation to oil in reservoir rock of Baolang oilfield couldn't start with till a relatively high pressure gradient was formed in it, in the case o{ existence of inreducible water only(no free water). It shows Imnany shapes of relative permeability curves, in which the straight line is comrron. In general, these curves are characterized bv high ineducilhle water saluratiol, low remaiming oil saturation with high relative perimeability and wider two-phase region. It is also shown tlrat the fects of pore-throat combilnation patterns and injected water quality on the relalive penmeability ('urves are (o11sirable.

Key words: Y anqi. Relative perneability curve, Shapc, Feature. Pore structure. W aler quality. (Baolang oilfield)