Abstract: Yaxi reservoir of Cretaceous is characterized by dense lithology, poor petrophysics, low porosity, low permeability and high shaliness. This paper comprehensively applied the various data from drilling, well logging, cutting logging, core analysis and production test, and statistically analyzed the consequences among lithology, petrophysical, petroliferous and electric properties. By defining these sensitive parameters and applying fuzzy analog optimum seeking method, the subordinate function between factor set and point set of reservoirs is established, obtaining corresponding matrix with this method. In the truncated processing of matrix, consideration of several geological parameters from well logs is used to judge their similarities and preferred rating, finally, offering results of the evaluation of reservoir characteristics. Field application of this method shows good effects in geological studies.

Key words: fuzzy mathematics, analog, reservoir evaluation, reservoir parameter