According to the principle of Archie equation, this paper puts forword the method using Rt-Ri crossing plot to discriminate oil and gas reservoir.

• 为了在油气田开采中准确地判别油气层，根据阿尔奇公式的基本原理，探讨了用真电阻率与侵入带电阻率交会图判别油气层的方法。