Abstract: The biohermal reservoirs with superior quality, wide distribution and higher reserves have been discovered in recent years in westermn Qaidam basin, mainly including algal reefs, stromatolites and thrombolites, based on field survey and classifications at home and abroad. Some lacustrine bioherms are also found, but not even in distribution and varied in thickness, hence hard to be explored and developed with traditional ways. This paper reviews the log responses of various types of bioherms using core and well log data, and proposes the features of logs suitable for these biohermal reservoirs. Also, fllowing the digital processing of these logs, the optimal discrimination functions for determination of different types of bioherm reservoirs are presented by means of optimal partition, cluster and regression methods. The results can be applied to the well log interpretations in order to achieve hghe-ficient and proper exploration and development of the reservoirs in Qaidam basin.

Key words: Qaidam basin, bioherm, reservoir, log response, discrimination